ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2010, Vol. 55, No. 12, pp. 1965–1969. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © I.Yu. Kotova, V.P. Korsun, 2010, published in Zhurnal Neorganicheskoi Khimii, 2010, Vol. 55, No. 12, pp. 2078–2082.
PHYSICOCHEMICAL ANALYSIS
OF INORGANIC SYSTEMS
Phase Formation in the System Involving Silver,
Magnesium, and Indium Molybdates
I. Yu. Kotova and V. P. Korsun
Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences,
ul. Sakh’yanovoi 8, UlanꢀUde, Buryat Republic, 670047 Russia
Received August 18, 2009
Abstract—The subsolidus region of the Ag2MoO4–MgMoO4–In2(MoO4)3 ternary salt system has been
studied by Xꢀray powder diffraction. The formation of new compounds Ag1 – xMg1 – xIn1 + x(MoO4)3
(
0
≤ x ≤
0.6) and AgMg3In(MoO4)5 has been established. The unit cell parameters of solidꢀsolution samples have been
determined. The Ag1 – xMg1 – xIn1 + x(MoO4)3 phase of variable composition has a NASICONꢀtype structure
(space group
formula unit and crystallizes in triclinic system (space group
ters: = 7.0374(5) = 17.932(1) = 6.9822(4) = 87.309(6)
R
3
c
) AgMg3In(MoO4)5 is isostructural to sodium magnesium indium molybdate of the same
1, = 2) with the following unit cell parameꢀ
= 100.832(6) = 92.358(6) . The
P
Z
a
Å,
b
Å,
c
Å,
α
°
,
β
°,
γ
°
compounds Ag1 – xMg1 – xIn1 + x(MoO4)3 and AgMg3In(MoO4)5 are thermally stable up to 960 and 1030°C,
respectively.
DOI: 10.1134/S0036023610120247
The interactions in systems containing molybdates AgIn(MoO4)2 join, where intermediate phases were
of monoꢀ, biꢀ and trivalent metals are of interest from
the standpoint of both revealing phase formation regꢀ
ularities and synthesizing new materials with various
important physicochemical properties. Compounds
that demonstrate crystallochemical similarity to
NASICONꢀtype ones with a high ionic conductivity
[1–5] are promising.
formed, was studied over the entire concentration
region in steps of 5–10 mol % and in the neighborꢀ
hood of new compounds, in steps of 2.0–2.5 mol %.
While equilibrium was attained, the phase composiꢀ
tion was monitored by Xꢀray diffraction.
To determine a possible homogeneity region in the
This work studies phase formation in the subsolidus
region of the system involving silver, magnesium, and
indium molybdates and determines the Xꢀray diffracꢀ
tion and thermal characteristics of ternary molybdates
and the conditions for their synthesis.
Ag2MoO4–MgMoO4–In2(MoO4)3 system, Ag1 – xMg1 –
x
In1 + x(MoO4)3 samples were prepared in
within the range 0.7 and stepwise annealed in air
in steps of 50 starting at 350 with intermediate
Δx = 0.1 steps
0
≤x≤
°С
°С
grinding every 20–30 h. The annealing duration was
50–100 h at every temperature. Every rise in temperaꢀ
ture was preceded by an Xꢀray diffraction study of a
sample. The homogeneity region boundaries were
determined by Xꢀray powder diffraction in airꢀ
quenched samples. The homogeneity extent was estiꢀ
EXPERIMENTAL
Silver, magnesium, and indium molybdates that
were previously synthesized by the solidꢀphase
method including the staged annealing of AgNO3
(pure for analysis grade), MgO (chemically pure mated by Xꢀray diffraction from both the absence of
grade), In2O3 (pure grade), and molybdenum trioxide
(chemically pure grade) in the stoichiometric ratio at
350–450 (Ag2MoO4), Ag2MoO4), 400–750 (MgMoO4),
impurity lines and the changes in the unit cell paramꢀ
eters of airꢀquenched samples.
Xꢀray diffraction studies were performed on a
Brukeraks D8 Advance automatic powder diffractoꢀ
and 400–800 С (In2(MoO4)3) served as initial compoꢀ
°
nents. The Xꢀray diffraction and thermal characterisꢀ
tics of the synthesized compounds agree satisfactorily
with data [6–9]. The Ag2Mg2(MoO4)3 and
AgIn(MoO4)2 double molybdates were synthesized by a
solidꢀphase method from the relevant neutral molybꢀ
dates as described in [10–12].
meter (Cu
K
radiation, graphite monochromator,
α
maximal angle
per point) and on an FRꢀ552 monochromator chamꢀ
ber (Cu 1 radiation, Ge internal standard).
2θ
= 90°,
0.01
°
–0.02 scan steps, 1 s
°
K
α
Differential thermal analysis was performed on an
MOM ODꢀ103 derivatograph (heating rate was
Phase formation in the Ag2MoO4–MgMoO4–
In2(MoO4)3 system was studied by the intersecting secꢀ
tions method in the subsolidus region. The MgMoO4– 10 K/min, sample size was 0.3–0.4 g).
1965
Kotova
