TY - JOUR

T1 - New triple molybdate Rb2AgIn(MoO4)3

T2 - synthesis, framework crystal structure and ion-transport behaviour

AU - Spiridonova, Tatyana S.

AU - Solodovnikov, Sergey F.

AU - Savina, Aleksandra A.

AU - Kadyrova, Yulia M.

AU - Solodovnikova, Zoya A.

AU - Yudin, Vasiliy N.

AU - Stefanovich, Sergey Yu

AU - Khaikina, Elena G.

PY - 2018/12/1

Y1 - 2018/12/1

N2 - A new triple molybdate, Rb2Ag1+3xIn1–x(MoO4)3 (0 ≤ x ≤ 0.02), was found in the course of a study of the system Rb2MoO4–Ag2MoO4–In2(MoO4)3 and was synthesized as both powders and single crystals by solid-state reactions and spontaneous crystallization from melts. The structure of Rb2Ag1+3xIn1–x(MoO4)3 (x ≈ 0.004) is of a new type crystallizing in the centrosymmetric space group Rc [a = 10.3982 (9), c = 38.858 (4) Å, Z = 12 and R = 0.0225] and contains (In,Ag)O6 octahedra and distorted Ag1O6 trigonal prisms linked by common faces to form [Ag(In,Ag)O9] dimers connected to each other via MoO4 tetrahedra into an open three-dimensional (3D) framework. Between two adjacent [Ag(In,Ag)O9] dimers along the c axis, an extra Ag2O6 trigonal prism with about 1% occupancy was found. The Ag1O6 and Ag2O6 prisms are located at levels of z ≈ 1/12, 1/4, 5/12, 7/12, 3/4 and 11/12, and can facilitate two-dimensional ionic conductivity. The 12-coordinate Rb atoms are in the framework cavities. The structure of Rb2AgIn(MoO4)3 is a member of the series of rhombohedral 3D framework molybdate structure types with a ≈ 9–10 Å and long c axes, which contain rods of face-shared filled and empty coordination polyhedra around threefold axes. Electrical conductivity of ceramics is measured by impedance spectroscopy. Rb2AgIn(MoO4)3 undergoes a `blurred' first-order phase transition at 535 K with increasing electrical conductivity up to 1.1 × 10−2 S cm−1 at 720 K. Thus, the compound may be of interest for developing new materials with high ionic conductivity at elevated temperatures.

AB - A new triple molybdate, Rb2Ag1+3xIn1–x(MoO4)3 (0 ≤ x ≤ 0.02), was found in the course of a study of the system Rb2MoO4–Ag2MoO4–In2(MoO4)3 and was synthesized as both powders and single crystals by solid-state reactions and spontaneous crystallization from melts. The structure of Rb2Ag1+3xIn1–x(MoO4)3 (x ≈ 0.004) is of a new type crystallizing in the centrosymmetric space group Rc [a = 10.3982 (9), c = 38.858 (4) Å, Z = 12 and R = 0.0225] and contains (In,Ag)O6 octahedra and distorted Ag1O6 trigonal prisms linked by common faces to form [Ag(In,Ag)O9] dimers connected to each other via MoO4 tetrahedra into an open three-dimensional (3D) framework. Between two adjacent [Ag(In,Ag)O9] dimers along the c axis, an extra Ag2O6 trigonal prism with about 1% occupancy was found. The Ag1O6 and Ag2O6 prisms are located at levels of z ≈ 1/12, 1/4, 5/12, 7/12, 3/4 and 11/12, and can facilitate two-dimensional ionic conductivity. The 12-coordinate Rb atoms are in the framework cavities. The structure of Rb2AgIn(MoO4)3 is a member of the series of rhombohedral 3D framework molybdate structure types with a ≈ 9–10 Å and long c axes, which contain rods of face-shared filled and empty coordination polyhedra around threefold axes. Electrical conductivity of ceramics is measured by impedance spectroscopy. Rb2AgIn(MoO4)3 undergoes a `blurred' first-order phase transition at 535 K with increasing electrical conductivity up to 1.1 × 10−2 S cm−1 at 720 K. Thus, the compound may be of interest for developing new materials with high ionic conductivity at elevated temperatures.

KW - crystal structure

KW - indium

KW - ionic conductivity

KW - powder X-ray diffraction

KW - rubidium

KW - silver

KW - triple molybdate

KW - PHASES

KW - PACKINGS

KW - SERIES

KW - CR

KW - SC

KW - R=AL

KW - SOLID-SOLUTION

KW - DIFFRACTION

KW - MG

KW - FE

UR - http://www.scopus.com/inward/record.url?scp=85056564821&partnerID=8YFLogxK

U2 - 10.1107/S2053229618014717

DO - 10.1107/S2053229618014717

M3 - Article

C2 - 30516143

AN - SCOPUS:85056564821

VL - 74

SP - 1603

EP - 1609

JO - Acta Crystallographica Section C: Structural Chemistry

JF - Acta Crystallographica Section C: Structural Chemistry

SN - 2053-2296

IS - 12

ER -