----------------------------------------------------------------------
<ref name=BouchardJr>
Solid-state studies of potassium molybdenum bronzes

First PageHi-Res PDF[503 KB]Citing Articles
George Henry Bouchard Jr., Jerome H. Perlstein , Michell J. Sienko
Inorg. Chem., 1967, 6 (9), pp 1682–1685
DOI: 10.1021/ic50055a016
Publication Date: September 1967


With 3.15: 1 molar ratio of  MoO3 : K2MoO4 in  a  two-compartment porcelain electrolytic 
cell, red  crystals were formed  at  570 C  [and blue crystals at 550 C] 


Crystals  of  red bronze  gave room-temperature  resistivities  of  the order of  1e4 ohm-cm; 
crystals of  blue bronze gave room-temperature resistivities ofthe order of 1e-4 ohm-cm. 

----------------------------------------------------------------------
<ref name=Bang>
Zeitschrift für Physik B Condensed Matter
1975, Volume 22, Issue 1, pp 1-12
ESR- and magnetic susceptibility measurements on the potassium molybdenum bronzes
G. Bang, G. Sperlich

10.1007/BF01325454


Magnetic and transport properties of the transition metal bronzes are determined by the extent of delocalization of the transition metal 4d-electrons. We report on ESR investigations of single crystals of the “red” potassium molybdenum bronze K0.33MoO3 and of the “blue” potassium molybdenum bronze K0.30MoO3. ESR spectra due to unpairedd-electrons are observed at both compounds. Analyzing the hyperfine structure we find that thed 1-electrons are delocalized over six molybdenum lattice sites in semiconducting K0.33MoO3. The same K0.33MoO3 crystals show another spectrum which is caused by pairs of exchange coupledd-electrons. Our results are compared with those from magnetic susceptibility measurements and are discussed in connection with the crystal structure of K0.33MoO3 and K0.30MoO3.

----------------------------------------------------------------------
<ref name=Dickens>
Some Electronic Properties of the Molybdenum Bronzes 
BY P. G. DICKENS  AND D. J.  NEILD 


In  this  paper  measurements  of  the 
diffuse reflectance  and  e.s.r.  spectra  of  the  compounds  K0.28M01.010J  (blue), 
K0.33Mo1.04O3 (red)  and  Na0.l8Mol.08O3  are presented  and interpreted  in  terms 
of a common model for their electronic structures.

Differ in composition from those reported by Wold et al but have identical
crystal structure. 

3.2 MoO3 : 1 K2MoO4 --> red K0.33Mo1.04O3,
3.5 : 1             --> blue K0.28Mol.0lO3, 
3.5 :1    Na2MoO4   --> purple Na0.18Mo1.08O3


Both the  blue  and the 
red  potassium bronze phases have layer structures,  the  layers  being  composed  of 
MoO6 octahedra sharing edges and corners. The potassium  atoms are situated 
between the layers. The structures  of the layers are different in the two  cases; in 
the red bronze the  basic unit comprises six  octahedra, in the  blue  compound, ten. 
The co-ordination  of  the  potassium  atoms  is  also different. The  purple  sodium 
bronze has a structure similar to the  corresponding sodium tungsten bronze,  i.e.,
a deficient perovskite in which the lattice symmetry is distorted from cubic to monoclinic.

The constant common feature of these structures is that the local octahedral 
environment  of  the  central molybdenum  atom  is maintained. The red potassium 
bronze  is  a semi-conductor whereas  the  blue phase is  a  metallic  conductor  above 
- 100°C.  The sodium bronze is a metallic conductor.

----------------------------------------------------------------------
<ref name=Ramanuja>
Journal of Crystal Growth
Volume 70, Issues 1–2, December 1984, Pages 476–483


Crystal growth of alkali metal molybdenum bronzes by a temperature gradient flux technique
K.V. Ramanujachary, M. Greenblatt, W.H. McCarroll
Department of Chemistry, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA
http://dx.doi.org/10.1016/0022-0248(84)90305-1, How to Cite or Link Using DOI
Permissions & Reprints


Single crystals of alkali metal molybdenum bronzes of the type: A0.9Mo6O17 with A = Na, K and A0.3MoO3 where A = K, Rb, Cs have been grown by the temperature gradient flux technique. Impure polycrystalline specimens of K0.33MoO3 and MoO3 like phases which may be sodium and potassium intercalates respectively, have also been observed. Optimal growth conditions determined for each of the phases are reported. Na0.9Mo6O17 is monoclinic and a quasi two-dimensional metallic conductor at room temperature, similar to Li0.9Mo6O17 and K0.9Mo6O17. A mechanism for the formation of bronze phases is proposed based on X-ray powder diffraction and DTA results.

Developed the gradient flux technique for Li0.32MoO3 and Li0.9Mo6O17 in addition to the previously unreported phase Li0.04MoO3

Typically, reduced phases could be Se
parated from the matrix by alternate leachings with
either hot 5% potassium carbonate or hot 5%
sodium dihydrogen phosphate and 2M hydrochloric
acid until the leachings were colorless. Potassium
carbonate, although more effective in dissolving the
matrix will noticeably attack all reduced products
except the A0.9Mo6O17 phases.


The systemA~MoO3with A = Na, K, Rb, Cs was
investigated over the range 0.05 ~ n ~ 0.80. The
particular phases formed depend not only upon the
value of n but also upon the range of temperature to
which various portions of the reacting mix were
subjected

The mix AnMoO3 will

  0.05 < n < 0.15 - no melting, sintering even at 730C, attack quartz
  0.20 < n < 0.50 - melting and flow towards cooling regions, bronzes.
  0.50 < n < 0.80 - considerable melting but only reduced phase is MoO2.
  
  The bronze cystals are found embedded in a matrix of A2Mo4O13 in each
  case. Their low melting points (mp = 568°C ~550°C, ~600°C, ~560°C and ~560°C for
  A = Li, Na, K, Rb and Cs respectively in A2Mo4O53) and their extensive presence as an ad
  mixture with the bronzes in the cooled products suggest that A2Mo4O13 serves as the flux for the
  growth ofthe crystals
  
  
Table 1 gives detailed results for various metals,compositions and temperatures.

for potassium:
 n   Th  Tc  Tr
0.20 621 527 612—550 No significant melting; well formed crystals of MoO3 near the cold end
0.25 621 527 612—550 Melting is appreciable; purple-red polycrystalline K0.9Mo6O17 is the only bronze phase observed
0.30 621 527 610—555 Crystallinity of K0.9M06O17 is improved; very small K0.9M06O17 crystals (1—2mm long)
 .   .   .   555—530 Polycrystalline blue potassium bronze (K0.3MoO3)
0.30 605 563 605—565 Large crystals up to 8mm long of blue K0.3MoO3; thin irregular plates of K0.9Mo6O17 less than 1 mm in largest dimension also form
0.34 605 563 605—565 Crystals of K0.3MoO3 of quality similar to those found for n = 0.30 predominate; K0.33MoO3 intermixed with MoO2 are secondary phases for T~580—600°C
0.35 621 527 610—555 Large crystals of K0.9Mo6O17 along with needles of MoO3 crystals of K0.9Mo6O17 well formed and 3—4mm long
 .   .   .   555—530 The crystallinity of K0.3MoO3 has improved; however, the size of the blue bronze is not comparable to that ofthe purple K.39Mo6O17
0.40 621 527 610—530 Phase distribution similar to that of n = 0.35 composition; crystals of K0.9Mo6O17 observed were smaller in size (~0.8-1.0mm length)


The temperature gradient flux growth technique has been used successfully to prepare large single
crystal specimens of purple Na 0.9Mo6O17, K0.9Mo6O17, blue K0.3MoO3, Rb0.3MoO3, red Cs0.3MoO3 bronzes and previously unreported
phases NayMoO3and KyMoO3which appear to be analogous with Li0.04MoO3 [8].
The optimum starting composition of the charge AnMoO3 for the growth of all bronzes found appears to be n = 0.35

hough it is assumed that its composition is close to Na0 04MoO3. This phase, which is readily attacked 
by dilute potassium carbonate solutions, is observed throughout the region of n = 0.05—0.20, and may be present at highvalues of n.



K03MoO3 and its rubidium analogue are of particular interest because of their highly anisotropic metallic properties
and the metal to semiconductor transition which takes place in each 180 K, and is associated with a charge density wave [2]


The fact that K0.3MoO3 is found at temperatures as high as 600°C, with the optimum temperature region being from about 565—575°C,
was unexpected since its electrolytic preparation requires a termperature of less than 570°C
in order to avoid the formation ofthe red bronze K0.33MoO3 [9,15]  
The red bronze is difficult to grow by both electrolytic and gradient flux method.

Cs0.3MoO3 and Cs0.59MoO3 single crystals: We have been able to grow the red bronze phase as good quality platelet crystals but not the blue Cs0.19MoO3

Cs0.3MoO3 is a semiconductor at all temperatures below ~540°C(its decomposition temperature) and undergoes a struc
tural phase transition accompanied by a color change under pressure [18].

MoO3 heated in vacuum forms Mo4O11 which has a slab structure.

Very little structural reorganization appears to be required of the Mo4O11 arrangemen
upon diffusion of the alkali metal ion to form the A0.9Mo6O17 bronze. This suggests that the forma
tion of A0.9Mo6O17 phases are facilitated by the presence of Mo4O11 and would explain why crystal
growth is promoted by a preheating ofthe charge at low temperatures.

The growth ofthe A03MoO3 phases is optimized in the temperature region ~575—530°C; 550°C

marks the onset of decomposition of some of the reduced molybdenum oxides (Mo9O26) and the for
mation ofothers (Mo17O47) [23].

----------------------------------------------------------------------
ssue		 J. Phys. France 
Volume 46, Number 10, octobre 1985	
Page(s)		1731 - 1742
DOI		http://dx.doi.org/10.1051/jphys:0198500460100173100

J. Phys. France 46, 1731-1742 (1985) 
DOI: 10.1051/jphys:0198500460100173100
Structural study of the charge-density-wave phase transition of the blue bronze : K0.3MoO3

J.P. Pouget, C. Noguera, A.H. Moudden et R. Moret

We present an X-ray study of the Peierls transition of the blue bronze K0.3MoO3, including the temperature dependence of the intensity of the first order and second order satellite reflections below Tc, a complete characterization of the structural fluctuations above Tc (both their temperature dependence and their anisotropy) and an accurate determination of the wave vector of the charge density wave above and below Tc. An analysis of the phase transition within a mean field theory is justified and yields reasonable values of the electron phonon coupling and of the Coulomb interaction between charge density waves. The value of the modulation wave vector is explained as resulting from the presence of two conducting quasi one dimensional bands crossing the Fermi level E F and of a third one located about 650 K above E F. The opening of an absolute gap at the Fermi level occurs at the Peierls transition due to the folding of one conduction band on the other, and leads to a semiconducting state below Tc. Finally our measurements do not reveal any clear commensurate-incommensurate phase transition in temperature.

----------------------------------------------------------------------
Synthesis of Molybdenum and Tungsten Bronzes at High Pressure

First PageHi-Res PDF[498 KB]Citing Articles
T. A. Bither , J. L. Gillson , H. S. Young
Inorg. Chem., 1966, 5 (9), pp 1559–1562
DOI: 10.1021/ic50043a020
Publication Date: September 1966

Synthesis at ~65 kbar from mixed elements, heated under pressure then quenched

 Two  new  NaxMoO3 bronze phases  have been  identified.  At 65 kbars pressure, wide variations 
of  both reactant  ratios  and  temperatures  gave  bright red  crystals, some having  edge lengths up to  1-2  mm, 
of  NaxMoO3  having  the  cubic perovskite  structure 
with x in  the limited range  0.90-0.97  and  cell dimen- 
sions from 3.847 to 3.853 A
 
 other  blue-black  NaxMoO3  phases
 
 Maintenance  of  high pressure  during  synthesis 
appears to be  essential to the formation of  cubic NaxMoO3.
It is slowly  attacked by warm, concentrated 
HCl, H2SO4, and H3PO4 and rapidly destroyed by dilute 
HNO3.  This bronze  also  becomes  coated with  MoO2 
after standing in air for a few weeks.  After long-term 
storage, a fresh red surface, even on very small crystallites, can  be  obtained  by ultrasonic  cleaning in warm 
water,  but MoO2  is still present  in  the bulk  product, as  evidenced  by  X-ray  diffraction  data.  Resistivity 
measurements  on  single  crystals  showed  cubic NaxMoO3  to have the same high conductivity and meiallic-type behavior
observed for the tungsten bronzes

 
Three  KxMo03 bronze phases have been identified.  In  the  presence  of  excess  K2MoO4, the 
cubic perovskite form  of  KxMoO3  mas  obtained  as 
bright, raspberry-red crystals, some with  edge lengths 
up  to  1-2  mm.  Again,  x  was  in  the  limited  range 
0.89-0.93,  and cell dimensions were from 3.917 to 3.920 
A.  These products  were  usually  free  from  Mo02. 
The stability  was  similar  to that  of  cubic  NaxMoO3, 
both  toward  acids  and  in  the  tendency  to  become 
coated with  MoO2.  Resistivity measurements  on 
single  crystals  also  indicated a  high  conductivity 
coupled with metallic-type behavior.

When  the  K2MoO4  content  was lowered  to  give 
calculated x values in the range 0.8-1.0, the red cubic 
KxMoO3  phase  was  obtained  admixed with  a  second 
blue phase of  small crystallite size.  This proved to be 
the tetragonal I-type bronze KxMoO3, with cell dimen- 
sions a  =  12.32, c  = 3.859 A, the structure of  which 
was initially determined by Magnéli for K0.48-0.57WO3.
Isolation  of  sufficient  material as  a  single  phase  for 
analysis proved  difficult,  but  an  approximate  x value 
of  0.5  was  obtained.  Again,  the  stability toward 
acids was similar to that of  the cubic Mo bronzes, but 
the  rate  of  formation  of  MoO2 was  slower. Single- 
crystal  resistivity measurements  were  suggestive  of 
metallic-type behavior,  although  very  little  change 
was observed from liquid helium to room temperature.

At  a  still  lower  K2MoO4 content  (calculated  x of 
0.4),  a  mixture  of  red  cubic  (trace), blue  tetragonal 
I,  and  a  third  bronze-colored  KxMoO3 phase  was 
formed. Single-crystal work  demonstrated this latter 
phase  to  be  monoclinic  in  space  group  Cm,  C2,  or 
C2/m with a = 14.31, b  = 7.71 c  = 6.38A,P = 92.33 deg. 
This is the K0.26MoO3  phase reported by Wold .

Two  RbxMoO3  bronze phases  were  ob- 
tained.  Either  a mixture of  irregularly shaped purple 
crystals  plus blue-black rods  (some  up to  2  mm  in 
length) or  the  blue-black  phase  alone  was  isolated.
----------------------------------------------------------------------
Journal of Solid State Chemistry
Volume 36, Issue 3, 1 March 1981, Pages 331–338


Crystal growth and electrical properties of lithium, rubidium, and cesium molybdenum oxide bronzes
Pierre Strobel*, Martha Greenblatt
Department of Chemistry, Rutgers University, New Brunswick, New Jersey 08903 USA
http://dx.doi.org/10.1016/0022-4596(81)90444-8, How to Cite or Link Using DOI
Permissions & Reprints


Crystals of Li0.33 MoO3 (blue), Rb0.23MoO3 (blue) and Cs0.31MoO3 (red) were grown by electrolysis from MoO3-M2MoO4 melts (M =alkali metal) with composition 70–77 mole% MoO3. Melts richer in M2MoO4 produced MoO2 only. Correlation is made between bronze formation and the coordination of Mo in the melt and in the equilibrium solid phase M2Mo4O13. Li0.33MoO3 and Cs0.31MoO3 are semiconductors with high-temperature-range activation energies 0.16 and 0.12 eV. Rb0.23MoO3 has an electrical behavior similar to that of blue KxMoO3 with a semiconductor-metal transition at (170 ± 5) K. ESR spectra observed in Li0.33MoO3 and Rb0.23MoO3 single crystals at 4.2 K show extensive delocalization of the 4d1 electron associated with Mo(V) centers. Attempts to grow molybdenum bronzes containing Ca or Y were unsuccessful.
----------------------------------------------------------------------
J. Phys. Soc. Jpn. 57 (1988) pp. 2557-2564  |Next Article|  |Table of Contents| 
|Full Text PDF (916K)| |Buy This Article|

URL: http://jpsj.ipap.jp/link?JPSJ/57/2557/
DOI: 10.1143/JPSJ.57.2557
Resonant Photoemission Study of Molybdenum Bronzes: K0.3MoO3, K0.33MoO3 and K0.9Mo6O17

Kazuo Terashima, Hideki Matsuoka, Kazuo Soda,1 Shigemasa Suga,1 Ryoichi Yamamoto and Masao Doyama

Department of Materials Science and Metallurgy, Faculty of Engineering, The University of Tokyo
1Synchrotron Radiation Laboratory, Institute for Solid State Physics, The University of Tokyo
(Received June 4, 1987)

The electronic structures of molybdenum bronzes K0.3MoO3, K0.33MoO3 and K0.9MoO17 have been systematically studied by means of the ultraviolet photoemission spectroscopy (UPS). Resonant photoemission spectra have been measured in the photon energy range from 32 eV to 100 eV. The measurements of total yield spectra have also been made on K0.3MoO3 and K0.9Mo6O17. Resonant enhancements of the photoemission have been observed in the valence and conduction bands with the contribution from the Mo 4d states for the excitation around hv=49 or 50 eV. It is found that the resonant effect is very weak for the structures at a binding energy EB=4.6 eV for K0.3MoO3, and K0.33MoO3. The magnitude of these resonances corresponds to the local electronic densities of Mo 4d states at the corresponding EB and can be qualitatively explained by the simple band structure model. ©1988 The Physical Society of Japan


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Synthetic Metals
Volume 29, Issues 2–3, 21 March 1989, Pages 219–226

Proceedings of the International Conference on Science and Technology of Synthetic Metals ICSM '88


Inorganic polymers and miscellaneous inorganic materials
Thermal conductivity of the potassium molybdenum bronzes
E.B. Lopes, M. Almeida
Departamento de Química, ICEN-LNETI, P-2686 Sacavém Codex, Portugal
J. Dumas, J. Marcus
Laboratoire d'Etudes des propriétés Electroniques de Solides, associated with Université Joseph Fourier, CNRS, B.P. 166X, F-38042 Grenoble Cedéx, France
http://dx.doi.org/10.1016/0379-6779(89)90903-X, How to Cite or Link Using DOI
Permissions & Reprints


Thermal conductivity measurements in the potassium blue bronze, K0.3MoO3, and in the red bronze, K0.33MoO3, in the range of 90–380K are reported. The blue conducting compound presents a large anomaly at 180K ascribed to the charge density wave transition, not present in the red insulating compound. The results of both compounds are compared and the temperature dependence of the thermal conductivity of the red bronze is used to estimate the phonon and electronic contribution of the blue bronze. The electronic contribution is found in qualitative agreement with the prediction based on the Wiedemann-Franz law.

Thermal  conductivity KT.  was  measured along  the  chain  axis  b  using  a 
standard  four  contact  slow  a.c.  (5e-3  Hz)  method,  relatively  to  a 
constantan  wire  as  previously described  [9].  Typical  dimensions  of  samples 
used  were ~4x0.4x0.1  mm 3  in  the  red  bronze  and  ~5x0.2x0.07 mm 3  in  the  blue 
bronze.  High  resolution  measurements  near  Tp  were  performed  both  while 
heating  or  cooling  at  rates  ~4  K/h,  imposing  thermal  gradients \leq 0.5K  on  the 
sample  measured with  12\mu m diameter  chromel-constantan  thermocouple  wires, 
glued  with  GE7031 varnish  to  the  sample.  In  other  cases  larger  gradients  in 
the  sample,  up  to  2K,  were used. 


At  room temperature K T  is  approximately 4 W/m/K. 
This  is  a  relatively  low  value  when  compared with  other  low  dimensional 
inorganic  materials  like  NbSe 9  where value  of  the  order  of  ~30 W/K/m have 
been reported  [I0].  The  smaller  value  of  the  thermal  conductivity  in  this 
bronze  suggests  a  reduced  mean free  path  of  the  phonons  due  to  increased 
defect  scattering,  most probably  the  disorder  of  the  distribution  of  the  K 
ions  that  randomly  occupy  vacant  positions  in  the  lattice  [8].  At  lower 
temperatures KT  increases aproximately as  1/T,  as  expected  for  an  insulator 
in  the  temperature range  near  the  Debye temperature.  Between 300  and  400K  it 
was  found  a  very  slight  increase  of  the  thermal  conductivity  with 
temperature.  This  increase  cannot  be  attributed  to  the  electronic 
contribution  since  the  electrical  conductivity  of  this  compound is  too  low, 
(\sigma(RT)~ 1e-4 mho/cm)  to  account  for  the  observed  increase. 


Thermal  conductivity measurements obtained  in  different  samples  of  the 
potassium  blue  bronze  in  the  range  90-380 K are  shown  in  Fig.  2.  At  room 
temperature  the  mean value  of  four  different  samples  measured was  5.0\pm 0.3 
W/K/m.  The  differences of  the  measurements in  the  different  samples  are 
essentialy determined  by  the  error  in  the  determination  of  the  geometrical 
factors.  In  constrast  with  the  smooth  and  featureless  behaviour  of  the 
thermal  conductivity  of  the  red  bronze,  the  thermal  conductivity  of  the  blue 
bronze  shows a  strong  anomaly  at  ~180 K, approximately at  the  same temperature 
where  it  is  observed  an  anomaly  in  the  electrical  resistivity.  The  thermal 
conductivity  anomaly  is  better  seen  in  the  derivative dKT/dT, also  shown  in 
Fig.  2,  which  presents  a  sharp  peak  at  180K.  No  signs  of  hysteretical 
behaviour  were found,  the  results  on  cooling  and  heating  being  equal  within 
the  experimental  resolution of  the  measurements  . 
The  thermal  conductivity KT  of  the  blue  bronze  can  be  decomposed  in  two 
contributions,  one  due  to  the  lattice  Kp  and  the  other  to  the  conducting   electrons Ke

The former decreases smoothly like 1/T.  The latter has parabolic growth from ~90 to 180K,
then linear, with stap kink at 180K  The electronic contribution is large.
 
<!----------------------------------------------------------------------

Solid State Communications
Volume 55, Issue 11, September 1985, Pages 951–955


Threshold-field behavior and switching in K0.3MoO3
Atsutaka Maeda, Tatsuo Furuyama, Shoji Tanaka
Department of Applied Physics, Faculty of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan
http://dx.doi.org/10.1016/0038-1098(85)90565-4, How to Cite or Link Using DOI
Permissions & Reprints

Nonlinear conductivity in K0.3MoO3 is measured down to 18 K. The threshold field of the nonlinear conduction, after having a minimum value around 50 K, increases with decreasing temperature, and then drastic delayed switching with a threshold field of the order of 100 V/cm is observed. In the switching, undamped regular oscillations between the pinned and depinned states of charge density wave can be seen, which suggests the existence of the well-defined depinned states in blue bronze.


Dumas  et  al.  found  nonlinear 
conductivity  accompanied  with  the  generation  of 
large  noise  in  blue  bronze,5  much  effort  has 

A  definite  threshold  field  ET  exists  in  the 
electric-field  dependence  of  the  Conductivity. 
According  to  the  measurement  down  to  60  K, 
however,  ET  decreases  monotonically  below  100  K 
with  decreasing  temperature.5,6

ET  begins  to  increase  below  about  50 
K.  With  further  decreasing  temperature,  drastic 
delayed  switching  with  a  very  high  ET  was  found.



suggests  the  existence  of  a metastable 
state  with  an  extremely  long  relaxation  time  in 
blue  bronze around  40  K.  Cava  et  al.  found  that 
the mean  relaxation  time  in  the  dielectric 
response  of  blue  bronze  obeys  an  Arrhenius 
behavior  with  an  activation  energy  of  829  K.

Anomalous nonlinear and noise generation resistivity at low temp.
------------------------------------------------------------------------
APS » Journals » Phys. Rev. B » Volume 60 » Issue 7
< Previous Article | Next Article >
Phys. Rev. B 60, 4525–4528 (1999)
Low-temperature behavior of the annealed molybdenum blue bronzes K0.3MoO3 and Rb0.3MoO3
Abstract
References
Citing Articles (8)
Download: PDF (68 kB) Export: BibTeX or EndNote (RIS)
B. Zawilski* and J. Richard 
Centre de Recherches sur les Très Basses Températures, Laboratoire associé à l’Université J. Fourier, CNRS, Boîte Postale 166 38042, Grenoble Cedex, France
J. Marcus and J. Dumas 
Laboratoire d’Etudes des Propriétés Electroniques des Solides, CNRS, Boîte Postale 166 38042, Grenoble Cedex, France
Received 4 February 1999; published in the issue dated 15 August 1999
When annealing molybdenum blue bronzes K0.3MoO3 and Rb0.3MoO3 in the presence of a metal (Ag or Cu), drastic changes of the resistivity are observed below T≈40 K in the three crystal directions. Nevertheless, dc conductivity and dielectric constant measurements still clearly exhibit the presence of a charge-density wave. Electronic paramagnetic resonance studies of annealed samples revealed a high concentration of Mo5+ sites with respect to untreated samples suggesting an additional conduction via orbital overlaps of the Mo5+ cations. This could also be responsible for some other anomalies observed in the blue bronzes at this temperature. These results are discussed in comparison with unannealed blue bronzes.
© 1999 The American Physical Society
URL:	http://link.aps.org/doi/10.1103/PhysRevB.60.4525
DOI:	10.1103/PhysRevB.60.4525
PACS:	 71.45.Lr, 72.15.Nj, 71.30.+h

In conclusion, the annealed molybdenum blue bronzes
with metal contacts show a plateau in the resistivity below
T ~40 K, increasing after thermal cycling
----------------------------------------------------------------------

Journal of Solid State Chemistry
Volume 128, Issue 2, 1 February 1997, Pages 256–260


Regular Article
Soft Chemical Modification of Blue Potassium Molybdenum Bronze
Nobukazu Kinomura, Katsuya Mizumoto, Nobuhiro Kumada
Institute of Inorganic Synthesis, Yamanashi University, Miyamae-cho 7, Kofu, 400, Japan
Faculty of Engineering, Yamanashi University, Miyamae-cho 7, Kofu, 400, Japan
http://dx.doi.org/10.1006/jssc.1996.7205, How to Cite or Link Using DOI
Permissions & Reprints


Hydrogen insertion compounds of general formula HxK0.28MoO3·zH2O have been obtained from blue potassium molybdenum bronze (K0.28MoO3) by the spillover technique using hydrogen gas in the presence of a Pt catalyst. The hydrogen insertion compounds are formed topotactically and the original blue bronze is regenerated by standing in air for at least >2 weeks. Although the values of x exceeding approximately 0.42 could not be determined by redox titration, the value of x was estimated to be 1.3 immediately after the hydrogen insertion for about 20 h. The hydrated hydrogen insertion compound undergoes intercalation reactions withn-alkylamines. The basal spacing of the intercalation compounds increases linearly with the number of carbon atoms. The electric resistivity of the hydrogen insertion compounds was increased by the order of 104as a result of amine intercalation.


Powdered blue bronze mixed with H2PtCl2.6H2O in vacuum reacted with H2 gas .

Exposure of product to air caused rapid exothermic reaction and some H2 converted to water givng HxK0.28MoO3·zH2O.

Change of basal spacing by H2, not by partial burning of H2 to H2O

----------------------------------------------------------------------
Journal of Solid State Chemistry
Volume 55, Issue 2, 15 November 1984, Pages 158–164


Electrochemical crystal growth in the cesium molybdate-molybdenum trioxide system
L.F. Schneemeyer, S.E. Spengler, F.J. Di Salvo, J.V. Waszczak, C.E. Rice
AT&T Bell Laboratories, Murray Hill, New Jersey 07974 USA
http://dx.doi.org/10.1016/0022-4596(84)90261-5, How to Cite or Link Using DOI
Permissions & Reprints


A systematic investigation of crystal growth in the cesium molybdate/molybdenum trioxide system is described. A previously unknown blue cesium molybdenum bronze phase has been prepared as well as the known red bronze, Cs0.33MoO3, and high-quality crystals of the Magneli-phase compound, γ-Mo4O11. This new blue bronze, with empirical formula, Cs0.19MoO2.85, is monoclinic with cell constants, a = 19.198(4) Å, b = 5.519(2) Å, c = 12.213(2) Å, and β = 119.44(2)°. Measurements of the susceptibility and of the resistivity vs temperature are reported. As is the case for other alkali molybdenum bronzes, the product formed is determined by the molar ratio of alkali molybdate to molybdenum trioxide and the melt temperature.

----------------------------------------------------------------------
		 J. Phys. Colloques 
Volume 44, Number C3, Juin 1983	
Conférence Internationale sur la Physique et la Chimie des Polymères Conducteurs
CONDUCTEURS ET SUPRACONDUCTEURS SYNTHÉTIQUES A BASSE DIMENSION
Page(s)		C3-1757 - C3-1760
DOI		http://dx.doi.org/10.1051/jphyscol/1983109

Conférence Internationale sur la Physique et la Chimie des Polymères Conducteurs
CONDUCTEURS ET SUPRACONDUCTEURS SYNTHÉTIQUES A BASSE DIMENSION

J. Phys. Colloques 44 (1983) C3-1757-C3-1760
DOI: 10.1051/jphyscol/1983109
PEIERLS TRANSITION IN THE QUASI-ONE DIMENSIONAL BLUE BRONZES K0.30MoQ3 AND RbQ0.30MoQ3

C. Schlenker1, C. Filippini1, J. Marcus1, J. Dumas1, J.P. Pouget2 and S. Kagoshima2 


Optical reflectivity data with polarized light shows blu epotassium bronze K0.30MoO3 to be quasi-1D metal.

Conductivity in CDW state is non-linear aboe a sharp threshold electric field.


----------------------------------------------------------------------
APS » Journals » Phys. Rev. B » Volume 62 » Issue 3
< Previous Article | Next Article >
Phys. Rev. B 62, 1504–1507 (2000)
Temperature dependence of the structural parameters of the host lattice in blue bronze K0.3MoO3
Abstract
References
Citing Articles (12)
Download: PDF (55 kB) Export: BibTeX or EndNote (RIS)
Mingliang Tian and Lin Chen 
Structure Research Laboratory, University of Science and Technology of China, Hefei 230026, Anhui, People’s Republic of China
Yuheng Zhang 
Structure Research Laboratory, University of Science and Technology of China, Hefei 230026, Anhui, People’s Republic of China
Center for Advanced Studies in Science and Technology of Microstructures (CASSTM), Nanjing 210093, People’s Republic of China
Received 9 December 1999; revised 17 February 2000; published in the issue dated 15 July 2000
Structural parameters of the host lattice in quasi-one-dimensional blue bronze K0.3MoO3 were measured in the range 10–300 K. It is found that the temperature dependence of the unit cell parameters a,b,c, cell volume V, and angle β, and parameters a[102] and d[2¯01] all present noticeable unusual changes in the slope near about 178 and 50 K, respectively. The change of the structural parameters near 178 K is in relation to the Peierls phase transition, while the second change near about 50 K may be an indication of some subtle variations in structures at 50 K.
© 2000 The American Physical Society
URL:	http://link.aps.org/doi/10.1103/PhysRevB.62.1504
DOI:	10.1103/PhysRevB.62.1504
PACS:	 71.45.Lr, 72.15.Nj, 61.10.Nz


At temperatures above 50 K,
the transport of the CDW above a small depinning electric field ET1 ~10–100 mV/cm involves a viscous damping due to Coulomb screening of the CDW fluctuation by normal carriers. 4 At lower temperatures below about 50 K, where the normal carriers become too small to provide screening, a drastic drop of damping for the sliding of the CDW occurs, and the CDW condensate moves almost rigidly above a large second abrupt threshold ET2 ~ 10–150 V/cm. 5,6

standard electrolytic reduction of a K2CO3 -MoO3 melt with a mole ratio of 1:4.35. 17
The starting mixture was melted in alumina crucible at 555 °C by using a vertical tube
furnace. A current of 20 mA was maintained through the melt for electrolysis about 4–10 h



It is seen that three parameters a, b, and c
all decrease with temperature from 300 to 178 K, and then
decrease more rapidly down to 50 K. The clear change of the
curve slope for three parameters were observed near the
Peierls transition 178 K. Below about 50 K, the parameters a
and c become almost temperature independent, while parameter b presents an observable upturn kink at 50 K, and then
shows slight expansion down to 10 K (the parameter b is
almost constant from 100 to 50 K.)

these results indicate that the thermal linear expansion of the unit cell is strongly anisotropic in
the studied temperature range

----------------------------------------------------------------------
Journal of Materials Science
20011115, Volume 36, Issue 22, pp 5511-5514
Infrared and EPR studies of the red potassium molybdenum bronze K0.33MoO3
Rui Xiong, Jing Shi, Qingming Xiao, Wufeng Tang, Hailing Liu, Decheng Tian
Download PDF (72 KB)
Abstract

Infrared reflectance and electron-paramagnetic-resonance (EPR) of the red bronze K0.33MoO3are presented. The infrared measurements at 300 K indicated that red bronze K0.33MoO3is a semiconductor with very strong anisotropy in the range. The presence of three sharp lines at bout 900 cm−1for P⊥bis in fact due to the intramolecular oscillations of oxygen inside one octahedron. The phonon oscillators near 500 cm−1for P⊥band P∥bassociate with the modification of the effective charge. The EPR signals can be attributed to electrons localized in the isolated Mo5+paramagnetic center. The difference of relative intensities of the EPR lines in 300 K and 100 K is due to the electronic excitation. The inhomogeneous broadening of the resonance lines is due to a g-factor distribution arising from crystalline field and spin-orbit coupling.
10.1023/A:1012466622001
----------------------------------------------------------------------

Journal of Physics: Condensed Matter Volume 3 Number 37
Yin Jiang et al 1991 J. Phys.: Condens. Matter 3 7129 doi:10.1088/0953-8984/3/37/003

Thermal study of the phase transitions of blue bronze K0.3MoO3

Yin Jiang, Zhi-guo Liu, Xue-Xuan Qu, X J Zhang and X Y Zhou

electrolytic reduction of  a K2CO3-MoO3 
melt with a K2CO3-to-MoO3 ratio of  1 to 4.32.

two specific heat anomalies at 240 and 180 K, which w


specific heats
  240K  Cp/R0=8.38 \Delta Cp/Cp=8.87%   \Delta T ~13.8 
  189K  Cp/R0=5.47 \Delta Cp/Cp=9.4%    \Delta T ~9.4

----------------------------------------------------------------------
Electron-beam irradiation effects on the charge-density-wave superlattice of K/sub 0. 30/MoO/sub 3/
Description/Abstract

The formation of a charge-density-wave (CDW) superlattice in the blue molybdenum oxide bronze K/sub 0.30/MoO/sub 3/ is found to be extremely sensitive to electron-beam irradiation. Short exposure of the samples to an electron beam completely destroys the CDW superlattice whereas the underlying main lattice remains largely intact. The radiation damage in the CDW superlattice is believed to be electronic in origin.

Authors:	Chen, C.H.; Schneemeyer, L.F.; Fleming, R.M.
Publication Date:	1984 Mar 15
OSTI Identifier:	 6791397
Resource Type:	Journal Article
Resource Relation:	Journal Name: Phys. Rev. B: Condens. Matter; (United States); Journal Volume: 29:6


----------------------------------------------------------------------


Tag this article Full text PDF (439 KB)

AbstractReferencesCited ByMetrics
The quasi-one-dimensional charge-density-wave (CDW) compounds (TaSe4)2I, the blue bronze K0.3MoO3 and the platinum chain compound KCP(Br) show a strong deviation from a Debye behaviour of the specific heat Cp at temperatures of several degrees Kelvin. To determine the origin of this specific heat `anomaly' in the case of K0.3MoO3, we have performed time-of-flight neutron scattering measurements and extracted a generalized phonon density of states (PDOS). The excess over a Debye behaviour at low energies in the generalized PDOS lies at the origin of the observed anomalous specific heat. We have used a simplified dispersion model based on experimental phonon dispersion curves to calculate the low-energy PDOS of the system. The model succeeds in reproducing the observed specific heat anomaly and establishes its lattice phonon origin. Similar calculations of the low-energy PDOS based on available phonon dispersion data for KCP allow us to state that the anomalous behaviour of the specific heat for this compound also has a phonon origin.


Issue 41 (13 October 1997)
Received 2 June 1997

The phonon density of states and low-temperature specific heat: the blue bronze K0.3MoO3 and the platinum chain compound KCP
H Requardt et al 1997 J. Phys.: Condens. Matter 9 8639

Issue 41 (13 October 1997)
Received 2 June 1997

Journal of Physics: Condensed Matter Volume 9 Number 41
H Requardt et al 1997 J. Phys.: Condens. Matter 9 8639 doi:10.1088/0953-8984/9/41/011
----------------------------------------------------------------------
Magnetic properties and 151Eu Mössbauer spectroscopy of a new molybdenum bronze:Eu0.08MoO3
J. Marcus, C. Escribe-Filippini, R. Chevalier, R. Buder
Centre National de la Recherche Scientifique, Laboratoire d'Etudes des Propriétés Electroniques des Solides, associated with Université Scientifique, Technologique et Médicale de Grenoble B.P. 166, 38042 Grenoble Cedex, France
http://dx.doi.org/10.1016/0038-1098(87)90799-X, How to Cite or Link Using DOI


The magnetic properties, the Mössbauer resonance between 2 K and 300 K, the low temperature specific heat have been studied on Eu0.08MoO3: a new molybdenum bronze. The magnetic transition which takes place at 4.3 K is due to the ordering of the MoV spin and not to the europium which stays in a trivalent state in the explored temperature range.

Using  a  similar  technique,  but  at  lower 
temperature  (T  <  850  K)  we  succeeded  in  growing 
single  crystals  of  a  new  family  of  mixed  rare-earth 
molybdenum  bronzes.  Their  general  formula  is 
Ln x Mo O3  with  0.07  <  x  <  0.1  We  have  already 
obtained several  compounds  of this series  where  Ln 

=  La  and  Ce,  Eu,  Gd  and  Lu.  The  first  compound 
investigated  is  Eu0.08MoO3   .  The  results  of 
resistivity, magnetic susceptibility, specific  heat and 
Mossbauer measurements will be discussed. 


======================================================================
This  new  compound  is grown  by electrolytic 
reduction  of  a  molten  mixture  of K2MoO4,  MoO 3 
and  E u 2 0  3  in  the  following  mole  ratio  1,  4.9  and 
0.1.  The starting matenals were melted in a  platinum 
crucible at 850 K  using a  vertical fu~ace.  A  current 
of  60  mA  was  maintained  through  the  melt  during 
about 3  hours  by means  of two platinum electrodes 
The crystals grown on the cathode,  usually consist of 
a  group  of  intergrown  single  crystals.  The  samples 
were  yellow  cubes of typical size of 2  x  2  x  2  mm 3. 
Electron  mmroprobe  analyses  gwe  the  molar  ratio 
Eu/Mo  =  0.080/1  with  a  precision  of  -+  0.005. 
Precise  determination of the structure  which should 
confirm the formula is not yet available

The  electrical  resistivity  has  been  measured 
between  40  K  and  300  K  in  a  flux  liquid  helium 
cryostat  with  a  standard  four  probe  configuratmn. 
Contacts  to  the  crystal  were  made  with silver paint. 
The  same  samples  in  the  same  configuratmn  were 
used  m  a  furnace  under He  atmosphere  to  measure 
resistivity  between  300  and  700  K.  F r o m   our 
electrical  conductivity  data,  we  established  that the 
europmm  molybdenum  bronze  is  a  semiconductor 
over  all  the range  of  temperature  investigated.  The 
room  temperature  resastavlty  is  of  10  Q.cm.  The 
carrier  actwatmn  energy  obtained  from  the  plot  of 
resistivity vs  1000/T is of 0.05  eV. 
======================================================================
----------------------------------------------------------------------



----------------------------------------------------------------------
10.1007/BF00722175
Journal of Materials Science Letters
August 1990, Volume 9, Issue 8, pp 929-931
Determination of the potassium composition in K x MoO3 (x=0.1−0.5) by EDX spectroscopy
T. Hiratta, Y. Fukuda


It  is  known  that  the  'blue  bronze'  K0.3 MoO3  is  a  one 
dimensional  conductor  along  the  crystallographic 
b-axis  and  the  metal-semiconductor  transition  of  a 
Pierls  type  occurs  at  about  180K  [1,  2],  whereas  the 
'red bronze' K0.33 MoO3 is highly anisotropic semicon- 
ductor  at  all  temperatures

With  x  =  0.5,  granular  particles  with  a  light  blue 
colour  are  observed,  indicating  the  formation  of  a 
different phase from that in KxMoO 3 with x  =  0.1  to 
0.4.


----------------------------------------------------------------------
The Reaction of Sodium Tungsten Bronze with Molybdenum(VI) Oxide. The Sodium Molybdenum Bronze

First PageHi-Res PDF[305 KB]
M. E. Straumanis , K. K. Irani
J. Am. Chem. Soc., 1952, 74 (8), pp 2114–2115
DOI: 10.1021/ja01128a516
Publication Date: April 1952

Negative results: searched but found no Molybdenum bronzes.

----------------------------------------------------------------------
Journal of the Chemical Society A: Inorganic, Physical, Theoretical Issue 0, 1968Journal Home | RSC Journals Paper Previous Article | Next Article  The crystal structure of dipotassium trimolybdate, K2Mo3O10; a compound with five-co-ordinate molybdenum(VI)
B. M. Gatehouse and P. Leverett
J. Chem. Soc. A, 1968, 1398-1405
DOI: 10.1039/J19680001398
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Dipotassium trimolybdate, K2Mo3O10, crystallises in the monoclinic system, space group C2/c, with unit cell dimensions a= 13·902, b= 7·914, c= 8·845 Å, β= 98°50′. Its structure, determined by three-dimensional Patterson and Fourier syntheses and refined by least squares, contains distorted MoO6 octahedra and MoO5 square pyramids which share edges to form infinite chains parallel to the c axis. These chains are held together by potassium ions occupying irregular ten-co-ordinate interchain positions. The analogous trimolybdates, Rb2Mo3O10 and Cs2Mo3O10, have been shown to be isostructural and preliminary data for the previously unreported Ag2Mo3O10 is given.

Crystalline dipotassium  trimolybdate in  the  form  of 
white acicular prisms was obtained from a melt produced by 
fusion  of  K2CO3,  and  MoO3,  in  the  molar  ratio  1 : 3.

----------------------------------------------------------------------

Microstructural Aspect of Electron Transfer in the Blue and Red Molybdenum Bronzes
D. Colaitis
Article first published online: 19 FEB 2006
DOI: 10.1002/pssb.2221650112
Copyright © 1991 WILEY-VCH Verlag GmbH & Co. KGaA

Issue 
physica status solidi (b)
Volume 165, Issue 1, pages 157–173, 1 May 1991




----------------------------------------------------------------------
10.1007/BF00722175
Journal of Materials Science Letters
August 1990, Volume 9, Issue 8, pp 929-931
Determination of the potassium composition in K x MoO3 (x=0.1−0.5) by EDX spectroscopy
T. Hiratta, Y. Fukuda


It  is  known  that  the  'blue  bronze'  K0.3 MoO3  is  a  one 
dimensional  conductor  along  the  crystallographic 
b-axis  and  the  metal-semiconductor  transition  of  a 
Pierls  type  occurs  at  about  180K  [1,  2],  whereas  the 
'red bronze' K0.33 MoO3 is highly anisotropic semicon- 
ductor  at  all  temperatures

With  x  =  0.5,  granular  particles  with  a  light  blue 
colour  are  observed,  indicating  the  formation  of  a 
different phase from that in KxMoO 3 with x  =  0.1  to 
0.4.


----------------------------------------------------------------------
The Reaction of Sodium Tungsten Bronze with Molybdenum(VI) Oxide. The Sodium Molybdenum Bronze

First PageHi-Res PDF[305 KB]
M. E. Straumanis , K. K. Irani
J. Am. Chem. Soc., 1952, 74 (8), pp 2114–2115
DOI: 10.1021/ja01128a516
Publication Date: April 1952

Negative results: searched but found no Molybdenum bronzes.

----------------------------------------------------------------------
Journal of the Chemical Society A: Inorganic, Physical, Theoretical Issue 0, 1968Journal Home | RSC Journals Paper Previous Article | Next Article  The crystal structure of dipotassium trimolybdate, K2Mo3O10; a compound with five-co-ordinate molybdenum(VI)
B. M. Gatehouse and P. Leverett
J. Chem. Soc. A, 1968, 1398-1405
DOI: 10.1039/J19680001398
Share | | |
Share on citeulike
|
Share on facebook
|
Share on twitter
| 
PDF
Rich HTML
Download Citation  
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Abstract Cited byRelated Content  

Dipotassium trimolybdate, K2Mo3O10, crystallises in the monoclinic system, space group C2/c, with unit cell dimensions a= 13·902, b= 7·914, c= 8·845 Å, β= 98°50′. Its structure, determined by three-dimensional Patterson and Fourier syntheses and refined by least squares, contains distorted MoO6 octahedra and MoO5 square pyramids which share edges to form infinite chains parallel to the c axis. These chains are held together by potassium ions occupying irregular ten-co-ordinate interchain positions. The analogous trimolybdates, Rb2Mo3O10 and Cs2Mo3O10, have been shown to be isostructural and preliminary data for the previously unreported Ag2Mo3O10 is given.

Crystalline dipotassium  trimolybdate in  the  form  of 
white acicular prisms was obtained from a melt produced by 
fusion  of  K2CO3,  and  MoO3,  in  the  molar  ratio  1 : 3.

----------------------------------------------------------------------

Microstructural Aspect of Electron Transfer in the Blue and Red Molybdenum Bronzes
D. Colaitis
Article first published online: 19 FEB 2006
DOI: 10.1002/pssb.2221650112
Copyright © 1991 WILEY-VCH Verlag GmbH & Co. KGaA

Issue 
physica status solidi (b)
Volume 165, Issue 1, pages 157–173, 1 May 1991

The electron transfer process is systematically examined in K0.33MoO3 semiconductor red bronze and in K0.30MoO3 metallic blue bronze as a direct consequence of cation-anion orbital overlaps. The critical interatomic distance below which the overlap occurs is established at about 0.196 nm. In K0.33MoO3, it is shown that closed localized molecular-type orbitals correlate the rigid units which characterize the MoO3 layers. In K0.30MoO3, the paths for collective electrons are three quasi-one dimensional Mo–O chains, with occurrence of transverse correlations between the two among them which are equivalent. The third chain connects two staggered rigid-unit columns. The coupling of the metal–semiconductor transition with the lattice modulation is investigated in correlation with low temperature structural slight rearrangements and atomic displacements. It is shown that a part of collective electrons can condense in collective localized orbitals which close in between two equivalent chains with the modulation periodicity. The extension of transverse correlations towards the third inequivalent chain is discussed in relation with orbital overlaps and with the two-band states model. Finally a microstructural model is proposed, which can describe in terms of interface modulation the conduction electron modulation and its incommensurability.
----------------------------------------------------------------------
Acta Chemica Scandinavica volume 5 (1951) 372-378
Contribution to the knowledge of the alkali tungsten bronzes
Arne Magnéli and Brigitta Blomberg





----------------------------------------------------------------------
----------------------------------------------------------------------
Sodium tungsten bronze {{chem|Na|''x''|WO|3}} was discovered by Wohler in 1825.<ref name=GreenMoTu/> 

<!--Potassium purple bronze-->
The electrical and magnetic properties between 2 K and 300 K, the low temperature specific heat and the crystal structure at 300 K have been studied on single crystals of K0.9Mo6O17 grown by the electrolytic reduction technique. K0.9Mo6O17 is found to be a quasi two-dimensional metal; this is consistent with the structural data. The transition which takes place below 120 K is due to the partial opening of a gap at the Fermi surface, possibly related to the onset of a charge density wave.<ref name=Buder/>


Purple bronzes {{chem|M|0.9|Mo|6|O|17}} M = Li, Na, K <ref name=Onoda/>

<!--Potassium purple bronze -->
Na and K molybdenum purple bronzes undergo  phase  transitions  to  the  CDW  states  at  about  105  K  (7 8)  and  70 K  (9),  respectively.<ref name=Onoda/>

<!--Potassium purple bronze -->
the  structure  of K0.9 bronze  determined  by  Vincent  et  al. (11)<ref name=Onoda/>
slabs parallel to the bc plane, 4 layers of MoO6 octahedra separated by KO12 icosahedra
linked to MoO4 tetrahedra.<ref name=Onoda/>

<!--Potassium purple bronze -->
K0.9Mo6O17 has temperature variation of the resistivity shows metallic conductivity and highly anisotropic behavior like Li0.9Mo6O17<ref name=Greenblatt/>

<!--blue bronzes -->
Li0.33MoO3 is blue bronze.<ref name=Tsai/>


<!--Potassium purple bronze -->
Studies  of  the electrical  and magnetic  prop- 
erties of  electrolytically  grown  single  crystals 
of K0.9Mo6017  have  shown  that  the  compound 
exhlbits  quasi  two-dimensional  behavior II .  The 
lattice  of K0.9Mo6017  is  hexagonal  and  the 
crystals  preferentially  grow as  platelets  whose 
plane  is  perpendicular  to  the ~  direction.  The 
conductivity  when measured  perpendicular  to  the 
c  direction  (in the plane  of  the  platelet)  is 
about  500  times  greater  than  that  found  parallel 
to  the  c direction. The  temperature  dependency 
of  both  the  conductivity  and  the  thermoelectric 
power  show an anomaly  at  approximately  120K<ref name=Greenblatt/>

<!--Blue lithium bronze -->
The crystal structure of Li0.33MoO3, the first structurally well-characterized triclinic bronze, has been determined from single-crystal X-ray diffraction data. Li0.33MoO3 crystallizes in space group  with a = 13.079(2), b = 15.453(2), c = 7.476(1) Å, α = 96.97(2), β = 106.56(2), γ = 103.368(9)°, Z = 24, and RF = 0.032 for 10,664 reflections with F2o ≥ 3σ(F2o). Distorted lithium and molybdenum octahedra form V2O5-type layers parallel to the ac plane. Each layer contains six unique MoO6 units and two unique LiO6 units. Four such layers, two of which are unique, are interconnected through edge and corner sharing to form a three-dimensional network structure. The location of lithium atoms at completely occupied octahedral sites establishes the stoichiometric composition LiMo3O9. Examination of the structure suggests that Li0.33MoO3 should be a semiconductor except along c where metallic conduction is possible.<ref name=Tsai/>

<!--Blue lithium bronze -->
Later, Greenblatt and co-workers  prepared single crystals of Li0.33MoO3  using electrolysis (5, 8)  and temperature gradient  flux  (9) techniques<ref name=Tsai/> 


<!--Thallium purple bronze -->
Thallium purple bronze and sodium purple bronze are similar in structure to potassium purple bronze.<ref name=Wangbo/>

<!--Potassium purple bronze -->
Potassium purple bronze is a 2D metal. It undergoes a CDW transition at 120K.  Below 120 K transport is mainly by holes, above 120 K by electrons.  Three different types of Mo atoms  <ref name=Wangbo/>

<!--Early reports of molybdenum bronze -->
Stavenhagen  and  Engels prepared  sodium molybdenum  bronze  by electrolytic reduction  of  fused sodium molybdate and Cannert prepared  the lithium, sodium,  and  potassium molybdenum  bronzes  by  electrolytic reduction.<ref name=Wold/>

Molybdenum bronze crystals were grown by  electrolytic reduction of  alkali metal molybdate-molybdenum(V1) oxide mixtures. Alumina crucible. 550 C (at 575-600C ormore, MoO2 s formed) <ref name=Wold/>
ker's  reagent grade sodium molyb- 
date, potassium molybdate,  and molybdic anhydride were dried 
for 12 hr.  a t  500'  before use.  The desired molar proportions of 
these materials were mixed  and fused for approximately 1 hr. a t  
650" in a platinum crucible.  The melt was removed and ground 
until it had the consistency of  a coarse powder.  The electrolytic 
cell was filled with this material and mounted as shown in Fig. 1. 
The furnace was  brought  up slowly  to the desired  temperature 
and electrolysis  begun  after waiting  a sufficient  interval  of  time 
for  the flux  material  to melt  completely.  Initially, a platinum 
disk  (4.5  was  used  as the cathode; later  a  seed  crystal 
was  substituted  to  obtain  large  crystals.  All the  electrolytic 
reduction reactions were carried out for a period  of  7-8 days a t  a 
current density of  10 ma./cm.z in  air

A blue-black bronze was formed at 550' 
and  a red  bronze was  the  product  at  560'.  From 
analytical  data  their  formulas  appear  to  be  K0.28Mol.02O3 and K0.26Mo1.01O3, respectively<ref name=Wold/>

A striking difference is ob- 
served for the two potassium bronzes with almost iden- 
tical  composition.  The  red potassium  bronze  K0.26- 
Mo1.0103 showed typical semiconduction  behavior with 
a  positive  temperature  dependency, whereas the  blue-black 
bronze  K0.28M01.0203 has a much lower resistivity  with 
an apparent transition from semiconductor to metallic 
behavior above  - 100'.<ref name=Wold/>


The red potassium bronze, red K0.26MoO3 is prepared by the electrolysis of fused salt mixtures of K2MoO4 and MoO3. Slightly different conditions give  blue bronze K0.28MoO3, the first being a typical semi-conductor while the second behaved as a metal.<ref name=Graham/>

<!-- molybdenum bronzes in general-->
Also A0.08MoO3 where A is a rare-earth.<ref name=GreenMoTu/>

<!-- molybdenum bronzes in general-->
Three families: blue bronzes A0.3MoO3 (A=K,Rb,Tl) quasi 1D metals (coductance 10^4 (Ohm cm)^-1;
red bronzes A0.33MoO3 (A=Li,Na,K,Rb,Cs,Tl) semiconducting (10^-4 (Ohm cm)^-1
purple bronzes A0.9Mo6O17 quasi-2D metals.  <ref name=GreenMoTu/>

<!-- molybdenum bronzes in general-->
Stavenhagen  and  Engels described  a  sodium  molybdenum  bronze  in  the  form  of a  dark  bluish-grayish  powder  formed  by  electrolytic 
reduction  of  fused  sodium  molybdate.<ref name=Popov/> 

<!--
Under water, indigo-blue needles with a metallic luster. By weight analysis Na2Mo5O15 
Soluble in nitric acid and aquaregia, and in lye,insoluble in HCl and Schwefelsäure
Die  Analyse  ergab  6.0  pCt.  Na  und  62.7  pCt.  Mo,  welche  Zusammensetzung bei Zurechnung  von  2.08  pCt. O  zu  der  Formel Na2Mo5O15 führen würde  
Die  Bronze scheidet sich  schnell in  hübschen Krystallen,  die  mit 
siedendem  Wasser  und  verdünnter  Salzsaure  gereinigt wurden,  an  der 
Kathode  ab.  Unter Wasser  erscheint  die Bronze  als indigblaue metall- 
glanzende Nadeln,  die beim Trocknen etwas vom Metallglanz  einbüssten 
und  eine dunkelblaue  Farbe  annahmen.  Die  mikroskopische  Unter-

<!-- other bronzes-->
Transport properties and magnetization measurements of the {{chem|K|''x''|MoO|2−δ}} (0≤x≤0.25) compound are reported. The compound crystallizes in the oxygen deficient MoO2 monoclinic structure with potassium atoms occupying interstitial positions. An unconventional metallic behavior with power-law temperature dependence is related to a magnetic ordering. Superconducting transition with small volume fraction is also observed near 7 K for a sample with low potassium composition.<ref name=Alves/>
----------------------------------------------------------------------

<!--Thallium blue bronze-->
<ref name=Collins/>

Single crystals of Tl0.3MoO3 blue bronze were grown by the temperature gradient flux technique for the first time. Tl0.3MoO3 crystalizes with monoclinic symmetry, space group C2, C2/m or Cm, a=18.486(1), b = 7.5474(6), c=10.0347(7), β = 118.377(6)° and appears to be isostructural with the K0.3MoO3 blue bronze. The physical properties of Tl0.3MoO3 are similar to those of the K3MoO3 and Rb3MoO3 phases. The resistivity of Tl0.3MoO3 is highly anisotropic and its temperature susceptibility (4.2–300K) decreases sharply with decreasing temperature near the transition seen in the resistivity. The onset of another transition <60K is also indicated by the susceptibility data. Non-linear current-voltage (I–V) characteristics observed at ∼70K above applied threshold voltages of the order of ∼300mV/cm suggest the sliding of charge density condensate.
----------------------------------------------------------------------
<ref name=WhSchnee/>
[Theoretical]
The electronic structure of the blue bronze A0.30MoO3 (A = K, Rb) was examined by performing tight-binding band calculations 
on a number of model chains and an Mo10O3o slab.  When normalized to A3M010030  (Le., half the unit cell), the bottom two d-block 
bands of an Mo,OO30 slab are partially filled.  The Fermi surfaces of these two bands are open along the interchain direction, in 
agreement with the experimental fact that the blue bronze is a pseudo-one-dimensional metal with good electrical conductivity 
along the chain direction b.  The Fermi surfaces of the two bands are curved due to interactions between adjacent M010032  chains, 
but the curvatures of the Fermi surfaces are opposite for the two bands.  Thus the two pieces of the first-band Fermi surface are 
nested to those of the second-band Fermi surface by a single wave vector q b  N 0.75b*, which explains why only one charge density 
wave occurs in the blue bronze.  For an Mo10O30 slab, the bottom  of  the third d-block band is calculated to lie above, but very 
close to,  the Fermi level (Le,, 0.012 eV above er). This feature is responsible for the temperature dependence of  q b  in  the blue 
bronze,  which  increases  g
----------------------------------------------------------------------
<ref name=Chin/>
According to the color, stoichiometry, and structure of
the compound, alkali molybdenum bronzes can be classi"ed
generally into three types: (1) blue bronze, A0.3MoO3
with A = K, Rb, Cs, and Tl; (2) red bronze, A0.33MoO3 with
A = Li, K, Rb, Cs, and Tl; (3) purple bronze, A0.9Mo6O17
with A=Li, Na, K, and Tl. Molybdenum bronzes are nonstoichiometric compounds.
----------------------------------------------------------------------
<!--Hydrogen bronzes-->

<ref name=Birtill/>
The enthalpies of formation of five hydrogen molybdenum bronze phases, HxMoO3 (0 < x < 2), have been determined by solution calorimetry. Values obtained for formation from H2(g) and MoO3(s) at 298.15°K were (kJ mole−1): H0.28MoO3, −18.2 ± 0.5; H0.34MoO3, −22.5 ± 0.6; H0.93MoO3, −56.5 ± 0.8; H1.68MoO3, −83.9 ± 1.6; and H2.0MoO3, −80.4 ± 2.1. The thermodynamic stabilities of these phases are discussed in relation to their observed electrochemical behavior.

Moo3  has  an  unusual  layer  structure  in 
which  infinite  chains  of  vertex-sharing  MoO6 
octahedra  are fused  together  by edge sharing 
to  form  corrugated  layers  (I);  


At  ambient  temperature  chemical  (2)  or electrochemical  (3)  reduction  in  aqueous 
acidic  media  leads  to  the  formation  of  hydrogen  molybdenum  bronzes  HxMoO3  (0 < x\leq 2).
In  these  compounds  hydrogen  is inserted  into  the  MoO3  matrix  with  only small  consequential
changes  in  the  lattice parameters  of the  latter  (4)

In  both  aqueous 
and  nonaqueous  media  MoO3  can  function 
as a  cathode  material  which  undergoes  the 
reversible  redox  reaction
1/x MoO3 + A+  + e <--> 1/x AxMoO3 (A = H,Li)

The  hydrogen  bronze  phases  HxMo03 
were  first  systematically  investigated  by 
Glemser  and  co-workers  (2)  and  a  more 
complete  structural  characterization  has 
been  published  recently  by  the  present 
authors  (4)

Four  distinct  phases are found  in  the range 
0 <x  \leq 2.  Ranges  of  homogeneity  exist  for 
three  of  these  phases  with  the  approximate 
limits:  blue,  orthorhombic,  0.23  <x  <  0.4; 
blue,  monoclinic,  0.85  <x  <  1.04;  and  red, 
monoclinic,  1.55 <X  <  1.72.  The  green, 
monoclinic,  fourth  phase  of  highest  hy- 
drogen  content  approximates  the  fixed 
composition  H2.0MoO3.


H  to is  attached  as  -OH  bonds  to  bridging  0 
atoms  within  an MoO3  layer.  This  mode  of H 
atom  attachment  is  similar  to  that  found  in 
the  corresponding  H,  W03  phases
----------------------------------------------------------------------
<ref name=Glemser/>
dann ist aus dem ermittelten Gesamtwassergehalt die Formel MoO2.H2O bzw. H2MoO3 abzuleiten.

<ref name=Ramanuja>
  K. V. Ramanujachary, D. M. Greenblatt, E. B. Jones, W. H. McCarroll (1993), "Synthesis and characterization of a new modification of the quasi-low-dimensional compound {{chem|KMo|4|O|6}}" Journal of Solid State Chemistry, volume 102, issue 1, pages 69–78 {{doi|10.1006/jssc.1993.1008}}
</ref>

<ref name=Alves>
  L. M. S. Alves, V. I. Damasceno, C. A. M. dos Santos, A. D. Bortolozo, P. A. Suzuki, H. J. Izario Filho, A. J. S. Machado, and Z. Fisk (2010), "Unconventional metallic behavior and superconductivity in the K-Mo-O system". Physical Review B, volume 81, issue 17, paper 174532 (5 pages) {{doi|10.1103/PhysRevB.81.174532}}
</ref>

<ref name=Buder>
  R. Buder, J. Devenyi, J. Dumas, J. Marcus, J. Mercier, C. Schlenker and H. Vincent (1982), "Two-dimensional electronic properties of the purple potassium molybdenum bronze K0.9Mo6O17" J. Physique Lett. 43, 59-65 {{doi|10.1051/jphyslet:0198200430205900}}
</ref>

<!-- Blue lithium bronze -->
<ref name=Tsai>
 P.P. Tsai, J.A. Potenza, M. Greenblatt, H.J. Schugar(1986), "Crystal structure of {{chem|Li|0.33|MoO|3}}, a stoichiometric, triclinic, lithium molybdenum bronze". Journal of Solid State Chemistry, volume 64, issue 1, pages 47–56 {{doi|10.1016/0022-4596(86)90120-9}}
</ref>


<ref name=Wold>
 A. Wold, W. Kunnmann, R. J. Arnott, and A. Ferreti (1964), "Preparation and properties of sodium and potassium molybdenum bronze crystals". Inorganic Chemistry, volume 3, issue 4, pages 545-547. {{doi|10.1021/ic50014a022}}
</ref>

<ref name=Schenkler>
 C. Schlenker ed. (1996), "Physics and Chemistry of Low-Dimensional Inorganic Conductors" Book, Springer, 481 pages. ISBN 9780306453045
</ref>

<ref name=Graham>
 J. Graham, N. C. Stephenson, A. D. Wadsley, and A. Wold (1965), "Potassium molybdenum oxide 'bronzes'" Nature, volume 206, pages 924-925 {{doi|10.1038/206924b0}} 
</ref>

<ref name=Stavenhagen>
  A. Stavenhagen, E. Engels (1895) "Ueber Molybdänbronzen" Berichte der deutschen chemischen Gesellschaft, volume 28, pages 2280-2281. {{doi|10.1002/cber.189502802213}}
</ref>

<ref name=Popov>
 B. N. Popov and H. A. Laitinen (1973), [http://scholarcommons.sc.edu/cgi/viewcontent.cgi?article=1078&context=eche_facpub "Electrochemical reduction of molybdenum(VI) compounds in molten lithium chloride-potassium chloride eutectic"]. Journal of the Electrochemical Society: Electrochemical Science and Technology, volume 120, issue 10. <!--{{doi|???}}-->
</ref>

<ref name=Whangbo87>
Band electronic structure of the purple potassium molybdenum bronze K0.9Mo6O17

First PageHi-Res PDF[660 KB]Citing Articles
Myung Hwan Whangbo , Enric Canadell , Claire Schlenker
Journal of the American Chemical Society, 1987, 109 (21), pp 6308–6313
DOI: 10.1021/ja00255a013
Publication Date: October 1987
</ref>

<ref name=Wangbo>
 E. Canadell and M.-H. Wangbo (1996), "Fermi surfaces instabilities in oxides and bronzes". In <ref name=Schenkler>
</ref>

<ref name=Collins>
  B.T. Collins, K.V. Ramanujachary, M. Greenblatt, and J.V. Waszczak (1985), "Charge-density wave instability and nonlinear transport in {{chem|Tl|0.3|MoO|3}}, a new blue molybdenum oxide bronze". Solid State Communications, volume 56, issue 12, pages 1023–1028. {{doi|10.1016/0038-1098(85)90863-4}}
</ref>

<ref name=WhSchnee>
  M. H. Whangbo and L. F. Schneemeyer (1986), "Band electronic structure of the molybdenum blue bronze {{chem|A|0.30|MoO|3}} (A = K, Rb)".  Inorganic Chemistry, volume 25, issue 14, pages 2424–2429. {{doi|10.1021/ic00234a028}}
</ref>

<ref name=Chin>
  Kin Chin, Kazuo Eda, Noriyuki Sotani, M.Stanley Whittingham (2002), "Hydrothermal synthesis of the blue potassium molybdenum bronze, {{chem|K|0.28|MoO|3}}" Journal of Solid State Chemistry, volume 164, issue 1, pages 81–87. {{doi|10.1006/jssc.2001.9450}}
</ref>

<ref name=Birtill>
  J.J. Birtill and P.G. Dickens (1979), "Thermochemistry of hydrogen molybdenum bronze phases {{chem|H|''x''|MoO|3}}". Journal of Solid State Chemistry, volume 29, issue 3, pages 367–372 {{doi|10.1016/0022-4596(79)90193-2}}
</ref>

<ref name=Glemser>
  Oskar Glemser, Gertrud Lutz (1950) "Über ein Hydroxydhydrid des Molybdäns". Naturwissenschaften, volume 37, issue 23, pages 539-540. {{doi|10.1007/BF00589341}}
</ref>