A new double molybdate of erbium and zirconium, its crystalline
structure and properties
Bair G. Bazarov
a
, Jibzema G. Bazarova
a
, Yunna L. Tushinova
a
, Leonid A. Solovyov
b
,
Sesegma G. Dorzhieva
a
, Enkhtuul Surenjav
c
, Jadambaa Temuujin
c, *
a
Baikal Institute of Nature Management SB RAS, Sakhyanovoy 8, 670047 Ulan-Ude, Russia
b
Institute of Chemistry and Chemical Technology SB RAS, Akademgorodok, 50/24, 660036 Krasnoyarsk, Russia
c
Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences, Ulaanbaatar 51, Mongolia
article info
Article history:
Received 6 December 2016
Received in revised form
13 January 2017
Accepted 18 January 2017
Available online 23 January 2017
Keywords:
Ceramics
Solid state reactions
X-ray diffraction
Crystal structure
Dielectric properties
abstract
A new double molybdate of erbium and zirconium, Er
2
Zr(MoO
4
)
5
was synthesized by a simple solid-state
reaction. The crystal structure was determined using powder X-ray diffraction data, the Rietveld method
and the derivative difference minimization method (DDM). The new phase crystallizes in the ortho-
rhombic space group Cmc2
1
. The dielectric properties and thermal expansion between 298 and 1073 K
were investigated. The synthesized compound showed an electrical conductivity of about 10
2
S cm
1
at
high temperature.
© 2017 Elsevier B.V. All rights reserved.
1. Introduction
The current interest in research of molybdates is caused by their
wide variety of structures and promising physical and chemical
properties. These materials are potential candidates for LEDs, laser
applications and solid electrolytes [1e4,17]. The formation of three
types double molybdates: Ln
2
Zr
3
(MoO
4
)
9
(Ln ¼ LaeTb),
Ln
2
Zr
2
(MoO
4
)
7
(Ln ¼ SmeHo, Y) and Ln
2
Zr(MoO
4
)
5
(Ln ¼ TbeLu, Y)
were revealed during investigation of phase equilibria in the oxide
systems Ln
2
O
3
eZrO
2
eMoO
3
[5] along the Ln
2
(MoO
4
)
3
eZr(MoO
4
)
2
equilibrium. Ln
2
Zr
3
(MoO
4
)
9
crystallizes in the trigonal crystal sys-
tem (space group Re3c), Ln
2
Zr
2
(MoO
4
)
7
in the monoclinic system
(space group C2/c). The crystal structures of representative com-
pounds of two types of single crystals Nd
2
Zr
3
(MoO
4
)
9
[6],
Ho
2
Zr
2
(MoO
4
)
7
[7] were also determined to be three-dimensional
framework type structures formed by linkage of the different
polyhedras. The crystalline structures of molybdates determine
their application. Therefore, synthesis of a new molybdates with a
variable structure could lead to a new material with possible
application in a different field. This work examines the synthesis
and characterization of a double erbium-zirconium molybdate with
a composition Er
2
Zr(MoO
4
)
5
, one representative of the
Ln
2
Zr(MoO
4
)
5
system.
2. Experimental
Erbium and zirconium molybdates were used for synthesis of
the double molybdate. The precursor molybdates were prepared
from respective analytical pure MoO
3
, ZrO
2
and Er
2
O
3
(99.9%).
Stoichiometric mixture was prepared based on the reaction:
Er
2
O
3
þ ZrO
2
þ 5 MoO
3
¼ Er
2
ZrðMoO
4
Þ
5
: (1)
The oxides for solid-phase reactions with a total mass of 2e3g
were weighed with an accuracy of 0.0005 g, ground together in an
agate mortar, placed in a platinum crucible and calcined in a muffle
furnace. To avoid loss of MoO
3
due to sublimation, calcination was
started at 623 K. Solid phase synthesis was carried out within the
temperature range of 623e1023 K with intermediate grinding of
samples. Phase purity was verified by powder X-ray diffraction
(XRD) by D8 Advance Bruker AXS (Germany) diffractometer. Pow-
der X-ray diffraction data for the analysis of the structures were
obtained on a diffractometer PANalytical X'Pert PRO (PIXcel
* Corresponding author.
E-mail address: jtemuujin@yahoo.com (J. Temuujin).
Contents lists available at ScienceDirect
Journal of Alloys and Compounds
journal homepage: http://www.elsevier.com/locate/jalcom
http://dx.doi.org/10.1016/j.jallcom.2017.01.173
0925-8388/© 2017 Elsevier B.V. All rights reserved.
Journal of Alloys and Compounds 701 (2017) 750e753