1070-4272/02/7506-1026 $27.00 C 2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 6, 2002, pp. 1026!1028. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 6, 2002,
Original Russian Text Copyright + 2002 by Bazarov, Fedorov, S. Bazarova, Zh. Bazarova.
Electrical Properties of Molybdates in the Systems
B. G. Bazarov, K. N. Fedorov, S. T. Bazarova, and Zh. G. Bazarova
Baikal Institute of Nature Management, Siberian Division, Russian Academy of Sciences,
Ulan-Ude, Buryatiya, Russia
Buryat State University, Ulan-Ude, Buryatiya, Russia
Received February 13, 2002
Abstract-The temperature dependence of conductivity of molybdates in the systems M
was studied. The starting molybdates and molybdates of 5 : 1 : 3 and 1 : 1 : 1 compositions,
formed in the systems, exhibit mixed conduction, turning ionic at high temperatures. The sharp bends in
linear portions of the temperature dependence of conductivity coincide with the temperatures of polymorphic
transitions in the corresponding molybdates.
Previously, the ternary salt systems K
have been studied  and
formation of molybdates with three dissimilar cations:
potassium, doubly charged metal, and zirconium, was
The compounds obtained have general formulas
where A = Mg, Mn, Ni, Co, Cu, Zn,
As shown by investigations, the structures of these
complex molybdates have the form of skeletons con-
stituted by ZrO
octahedra and MoO
hedra connected via oxygen atoms. The structures of
these compounds contain large voids, which can ac-
commodate cations of alkali metals and, in particular,
potassium [4, 5].
At an appropriate geometrical arrangement of
channels and their filling with potassium cations, con-
ditions for fast ionic transport may be fulfilled in
skeleton structures and the compounds in question
may possess properties of solid electrolytes.
The aim of this study was to analyze the electrical
properties of starting molybdates forming the sys-
and ternary mo-
lybdates of compositions 5 : 1 : 3 and 1 : 1 : 1.
Molar ratio of starting molybdates.
The temperature dependences of conductivity s,
dielectric constant e, and dielectric loss tangent tan d
were studied on an experimental setup by the method
proposed by Vest and Tallan ; the values of s, e,
and tan d were measured under ac conditions on an
E8-4 ac bridge with an R-5025 resistance box serving
to extend the range of tan d measurements in the sam-
ples. The dc current was measured with an E6-13A
teraohmmeter at fixed voltages across a sample (30
and 60 mV).
The electronic transport numbers t
as the ratio of the electronic conductivity s
sured under dc conditions, to the total conductivity
, measured under ac conditions at a chosen
temperature of experiment (s
is the ionic conduc-
Samples for electrical measurements had the form
of pellets 1 mm thick with area of 74375 mm
The pellets were obtained by compaction of powdered
preparations, with their subsequent annealing at a tem-
perature equal to 2/3 T
of the corresponding com-
As electric contacts served platinum paste fired-in
at 500oC on the pellet surface.
Figure 1 presents in the form of Arrhenius plots
the temperature dependences of conductivity of a part
of molybdates studied, which are the conventional
straight lines. The activation energies of conductivity,