ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2010, Vol. 55, No. 2, pp. 162–166. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © V.N. Krasil’nikov, A.P. Shtin, L.A. Perelyaeva, I.V. Baklanova, A.P. Tyutyunnik, V.G. Zubkov, 2010, published in Zhurnal Neorganicheskoi Khimii, 2010,
Vol. 55, No. 2, pp. 167–172.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
Synthesis and Physicochemical Study of M4Na2V10O28 · 10H2O
(M = K, Rb, NH4)
V. N. Krasil’nikov, A. P. Shtin, L. A. Perelyaeva, I. V. Baklanova,
A. P. Tyutyunnik, and V. G. Zubkov
Institute of SolidꢀState Chemistry, Ural Division, Russian Academy of Sciences,
Pervomaiskaya ul. 91, Yekaterinburg, 620041 Russia
Received April 27, 2008
Abstract—The formation conditions and physicochemical properties of binary decavanadates
M4Na2V10O28 · 10H2O (M = K, Rb, NH4), synthesized by crystallization from saturated solutions of the
NaVO3–MH2AsO4–H2O systems, were studied by chemical analysis, Xꢀray powder diffraction, microscopy,
thermogravimetry, and IR spectroscopy. To optimize the synthesis conditions of M4Na2V10O28 · 10H2O, the
(1 –
x)NaVO3 · 2H2O ·
xMH2AsO4–H2O (0.2
≤
x ≤ 0.8) isomolar series method was applied to studying the
interaction in the NaVO3–MH2AsO4–H2O systems (M = K, Rb, Cs) at the 0.4 mol/L total molar concentraꢀ
tion of NaVO3 and MH2AsO4 in solutions. The studied M4Na2V10O28 · 10H2O compounds were shown to be
isostructural with triclinic crystals (Z = 1, space group P1 ), and their unit cell parameters were estimated.
DOI: 10.1134/S003602361002004X
Alkaline and ammonium decavanadates are usually were isolated from the mother liquor by vacuum filtraꢀ
synthesized by addition of mineral acids to metavanaꢀ
date solutions [1]:
tion, washed with acetone, and dried at ~50°C. The
conditions of the M4Na2V10O28 10H2O synthesis
were optimized by preparation of (1 – )NaVO3 ·
2H2O · MH2AsO4–H2O isomolar series for 0.4 mol/L
total molar concentration of NaVO3 · 2H2O and
MH2AsO4. Parameter was varied from 0.2 to 0.8. The
criterion of achieved equilibrium in the system was the
constant vanadium concentration in the liquid phase.
The crystals of resulting compounds were filtered off
in vacuum and dried at 22°C to constant weight. Synꢀ
⋅
x
6−
10VO3− + 4H+
V10O + 2H2O.
28
(1)
x
Evaporating of a NH4VO3 and NaH2PO4 aqueous
solution at a room temperature, the authors of [2]
managed to isolate single crystals of binary ammoꢀ
nium sodium decavanadate (NH4)4Na2V10O28 · 10H2O
and to study its crystal structure by Xꢀray diffraction.
This work was undertaken in order to study the forꢀ
mation conditions and properties of a series of isoꢀ
structural binary decavanadates M4Na2V10O28 · 10H2O
(M = K, Rb, NH4). Preliminary information on the
existence and properties of these compounds was
reported earlier in [3].
x
thesized decavanadates M4Na2V10O28 10H2O (M =
⋅
K, Rb, NH4) were tested for arsenic, with negative
results in all the cases.
The completeness of reactions and purity of synꢀ
thetic products were monitored by microscopic and
powder diffraction analyses based on Powder Diffracꢀ
tion File PDF2 (Release 2004, ICDD, USA). All
Xꢀray powder diffraction patterns were recorded with
EXPERIMENTAL
For synthesis of M4Na2V10O28 · 10H2O compounds,
we used the method of crystallization from solutions of
a STADIꢀP automated diffractometer (Cu
K
radiaꢀ
α
1
tion, 2
θ
= 2°–120° with the increment
Δ
2 = 0.02°).
θ
NaVO3–MH2AsO4–H2O systems (M = K, Rb, NH4
)
based on the reaction [3]
Polycrystalline silicon (
a
= 5.43075(5) Å) was used as
the external and internal references. The microscopic
analysis was carried out with a POLAM Sꢀ12 polarizaꢀ
tion microscope in transmitted light. The IR spectra
were recorded with a Spectrum One IR spectrophoꢀ
tometer in the frequency range 4000–400 cm–1. Therꢀ
mal analysis was carried out with a Qꢀ1500D derivatoꢀ
graph at a heating rate of 10 K/min. The chemical
analysis of vanadium, arsenic, and alkali metals was
10NaVO3 + 4MH2AsO4 + 8H2O
(2)
= M4Na2V10O28 ⋅10H2O + 4Na2HAsO4.
Vanadium was introduced into a solution in the
form of NaVO3 · 2H2O. Alkali metal and ammonium
dihydroorthoarsenates for the experiments were synꢀ
thesized by addition of concentrated arsenic acid to
their carbonates with further evaporation of solutions
on a water bath. The resulting crystals of MH2AsO4 carried out by standard techniques. The initial
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