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Russian Journal of Applied Chemistry, Vol. 76, No. 3, 2003, pp. 497! 499. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 3,
2003, pp. 512!514.
Original Russian Text Copyright + 2003 by Sorokin, Rakov, Fedorov, Zakalyukin.
Synthesis and Electrical Properties
of Ammonium Fluorostannates(II)
N. I. Sorokin, E. G. Rakov, P. P. Fedorov, and R. M. Zakalyukin
Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow, Russia
Mendeleev Russian University of Chemical Engineering, Moscow, Russia
Received December 5, 2001; in final form, July 2002
Abstract-With the aim of developing new fluorine-conducting solid electrolytes, the compound NH
was synthesized and its electrical conductivity and thermal behavior were studied.
Tin(II) fluoride SnF
forms compounds MSnF
(M is Pb, Ba, or Sr) and MSn
(M is NH
, Na, K,
Rb, Cs, or Tl), which have high unipolar electrical
conductivity with respect to fluoride ions [1, 2]. In-
creased interest in solid electrolytes derived from
is stimulated by prospects of their application in
all-solid-state power sources, sensors, and other elec-
trochemical apparatus. At the same time, successful
application of solid electrolytes in practice requires
reliable synthesis procedures to obtain materials with
well reproducible chararacteristics.
In this work, ammonium trifluorostannate(II)
was prepared and its electrical conductivity
Ammonium trifluorostannate(II) was synthesized
from tin(II) oxide, which, in turn, was prepared from
solution by adding a solution of NH
pH 9.5, separating the precipitate, repeatedly washing
with distilled water, and heating the Sn(OH)
sion for 435 h. The SnO and NH
tions in a molar ratio of 1 : 1.5 were dissolved in
distilled water at 60370oC, and the solution was
evaporated on a water bath until a precipitate formed,
which was filtered off after cooling the solution and
dried at room temperature.
Chemical analysis was performed as follows. Ap-
proximately 0.2-g portion was dissolved in hydro-
chloric acid, and tin(II) was determined by direct titra-
tion with an iodine solution in the presence of starch.
The relative eror of the determination was less than
2%. The ammonia content was determined according
to . The relative determination error was less than
1%. The content of fluoride ions was not determined.
Found, mol %: NH
9.5; Sn(II) 59.5.
. Calculated, mol %: NH
9.31; Sn(II) 61.34.
The product yield with respect to tin(II) was
92.4%. According to the X-ray phase analysis (HZG-4
radiation), the samples studied
are single-phase, and their structure (trigonal crystal
system, a = 6.841(1) and c = 15.930(4) A, Fig. 1a)
corresponds that of NH
. The values available
from Powder Diffraction File, Data Cards, JCPDS,
no. 3330081, are a = 6.842 A and c = 15.92 A.
Electrophysical properties were studied by im-
pedance spectroscopy with a VM-507 impedansom-
eter (frequency range 5 Hz3500 kHz, resistance range
1 W310 MW) in a vacuum (~0.1 Pa). The electrodes
were made from DAG-580 graphite paste (the Nether-
lands). The electrical conductivity s was measured on
pellets 5 mm diameter and 234 mm thick, obtained
Fig. 1. X-ray diffraction patterns of ammonium fluorostan-
nates(II). Sample: (a) initial (NH
) and (b) subjected
to temperature measurements (NH
(2q) Bragg angle.