| Autor: |
Spiridonova TS; Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Sakhyanova St. 6, Ulan-Ude 670047, Buryat Republic, Russian Federation., Solodovnikov SF; Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Akad. Lavrentiev Avenue 3, Novosibirsk 630090, Russian Federation., Savina AA; Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Sakhyanova St. 6, Ulan-Ude 670047, Buryat Republic, Russian Federation., Kadyrova YM; Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Sakhyanova St. 6, Ulan-Ude 670047, Buryat Republic, Russian Federation., Solodovnikova ZA; Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Akad. Lavrentiev Avenue 3, Novosibirsk 630090, Russian Federation., Yudin VN; Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Akad. Lavrentiev Avenue 3, Novosibirsk 630090, Russian Federation., Stefanovich SY; Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation., Khaikina EG; Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Sakhyanova St. 6, Ulan-Ude 670047, Buryat Republic, Russian Federation. |
| Abstrakt: |
A new triple molybdate, Rb 2 Ag 1+3x In 1-x (MoO 4 ) 3 (0 ≤ x ≤ 0.02), was found in the course of a study of the system Rb 2 MoO 4 -Ag 2 MoO 4 -In 2 (MoO 4 ) 3 and was synthesized as both powders and single crystals by solid-state reactions and spontaneous crystallization from melts. The structure of Rb 2 Ag 1+3x In 1-x (MoO 4 ) 3 (x ≉ 0.004) is of a new type crystallizing in the centrosymmetric space group R-3c [a = 10.3982 (9), c = 38.858 (4) Å, Z = 12 and R = 0.0225] and contains (In,Ag)O 6 octahedra and distorted Ag1O 6 trigonal prisms linked by common faces to form [Ag(In,Ag)O 9 ] dimers connected to each other via MoO 4 tetrahedra into an open three-dimensional (3D) framework. Between two adjacent [Ag(In,Ag)O 9 ] dimers along the c axis, an extra Ag2O 6 trigonal prism with about 1% occupancy was found. The Ag1O 6 and Ag2O 6 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 Rb 2 AgIn(MoO 4 ) 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. Rb 2 AgIn(MoO 4 ) 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. |
