Spiridonova Tatyana S, Solodovnikov Sergey F, Savina Aleksandra A, Kadyrova Yulia M, Solodovnikova Zoya A, Yudin Vasiliy N, Stefanovich Sergey Yu, Khaikina Elena G
Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Sakhyanova St. 6, Ulan-Ude 670047, Buryat Republic, Russian Federation.
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Akad. Lavrentiev Avenue 3, Novosibirsk 630090, Russian Federation.
Acta Crystallogr C Struct Chem. 2018 Dec 1;74(Pt 12):1603-1609. doi: 10.1107/S2053229618014717. Epub 2018 Nov 12.
A new triple molybdate, RbAgIn(MoO) (0 ≤ x ≤ 0.02), was found in the course of a study of the system RbMoO-AgMoO-In(MoO) and was synthesized as both powders and single crystals by solid-state reactions and spontaneous crystallization from melts. The structure of RbAgIn(MoO) (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 octahedra and distorted Ag1O trigonal prisms linked by common faces to form [Ag(In,Ag)O] dimers connected to each other via MoO tetrahedra into an open three-dimensional (3D) framework. Between two adjacent [Ag(In,Ag)O] dimers along the c axis, an extra Ag2O trigonal prism with about 1% occupancy was found. The Ag1O and Ag2O 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 RbAgIn(MoO) 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. RbAgIn(MoO) undergoes a `blurred' first-order phase transition at 535 K with increasing electrical conductivity up to 1.1 × 10 S cm at 720 K. Thus, the compound may be of interest for developing new materials with high ionic conductivity at elevated temperatures.
在对Rb₂MoO₄-Ag₂MoO₄-In₂(MoO₄)₃体系的研究过程中发现了一种新型的三钼酸盐RbAgIn(MoO₄)₄(0 ≤ x ≤ 0.02)，并通过固态反应以及熔体自发结晶的方式合成了该化合物的粉末和单晶。RbAgIn(MoO₄)₄(x ≉ 0.004)的结构属于一种新型结构，其在中心对称空间群R-3c中结晶 [a = 10.3982 (9), c = 38.858 (4) Å, Z = 12且R = 0.0225]，包含(In,Ag)O₆八面体和扭曲的Ag₁O₉三角棱柱，它们通过共面相连形成[Ag(In,Ag)O₄]二聚体，这些二聚体通过MoO₄四面体相互连接形成一个开放的三维(3D)框架。在沿c轴的两个相邻[Ag(In,Ag)O₄]二聚体之间，发现了一个占有率约为1%的额外Ag₂O₉三角棱柱。Ag₁O₉和Ag₂O₉棱柱位于z ≉ 1/12、1/4、5/12、7/12、3/4和11/12的位置，有助于二维离子传导。12配位的Rb原子位于框架空腔中。RbAgIn(MoO₄)₄的结构是菱面体3D框架钼酸盐结构类型系列的一员，其a ≉ 9 - 10 Å且c轴较长，该系列结构在三重轴周围包含由面共享的填充和空配位多面体组成的棒状结构。通过阻抗谱测量陶瓷的电导率。RbAgIn(MoO₄)₄在535 K时经历“模糊”的一级相变，在720 K时电导率增加至1.1×10⁻³ S cm⁻¹。因此，该化合物对于开发高温下具有高离子电导率的新材料可能具有重要意义。
