1070-4272/05/7812-2022 + 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 12, 2005, pp. 2022!2023. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 12, 2005,
Original Russian Text Copyright + 2005 by Khamaganova, Oshorova.
Solid Solutions (0 < x <3)
T. N. Khamaganova and V. K. Oshorova
Baikal Institute of Nature Management, Siberian Division, Russian Academy of Sciences, Ulan-Ude,
Geological Institute, Siberian Division, Russian Academy of Sciences, Ulan-Ude, Buryatia, Russia
Received August 24, 2005
Abstract-Samples of a continuous series of Ba
3 ! x
solid solutions (0 < x < 3), crystallizing
in the trigonal crystal (system, space group R3
) were synthesized by solid-phase reactions. Formation of a con-
tinuous series of solid solutions in the system was confirmed by X-ray phase analysis. The X-ray characteris-
tics of phases of variable composition were determined.
Complex borates M
), where M is alkaline-
earth element Ba or Sr and R is rare-earth element
(REE) [13 6], are of interest as materials for microelec-
tronics and nonlinear optics. Variation of the cationic
composition allows purposeful synthesis of phases
and makes it possible to elucidate the influence ex-
erted by the composition and structure on their char-
acteristics. Since double borates Ba
crystallize in the same structural type
[3, 4], formation of a continuous series of solid solu-
tions would be expected.
In this study, we examined the possibility of for-
mation of solid solutions based on double borates of
alkaline-earth elements and samarium, with the com-
3 ! x
, by isovalent substitu-
tion of Sr
. The x value was varied from
0 to 3 with a step of 0.5.
Polycrystalline samples were synthesized by solid-
phase reactions from Sm
(content of the main com-
ponent no less than 99.99%), BaCO
ultrapure grade, and H
of chemically pure grade.
Mixtures of stoichiometric amounts of the initial re-
agents were calcined in platinum crucibles in air with
repeated intermediate grindings. Barium and stron-
tium carbonates were preliminarily annealed at 400oC,
and samarium oxide, at 800oC, for 5 h. The syn-
thesis temperature was gradually raised from 600oC
to 1000oC, with a step of 100oC, over a period of 703
80 h. Single-phase samples were prepared by anneal-
ing at 1000oC for 20325oC. The phase composition of
the compounds studied and the attainment of equilibri-
um were monitored by X-ray phase analysis (Bruker
D8 Advance diffractometer, Cu
The X-ray patterns diffraction of all the compounds
obtained (Fig. 1) are similar in the positions and rela-
Fig. 1. X-ray diffraction patterns of the compounds.
) Relative intensity and (d) interplanar spacing.