TY - JOUR

T1 - Synthesis, Structure, and Conductivity of Alluaudite-Related Phases in the Na2MoO4–Cs2MoO4–CoMoO4 System

AU - Yudin, Vasiliy N.

AU - Zolotova, Evgeniya S.

AU - Solodovnikov, Sergey F.

AU - Solodovnikova, Zoya A.

AU - Korolkov, Iliya V.

AU - Stefanovich, Sergey Yu

AU - Kuchumov, Boris M.

PY - 2019/1/17

Y1 - 2019/1/17

N2 - Phase formation study of the Na2MoO4–Cs2MoO4–CoMoO4 system resulted in new cesium-containing alluaudite-related phases. The solid solution Na4–2x-yCsyCo1+x(MoO4)3 (0 ≤ x, y ≤ 0.30), based on the alluaudite-type Na4–2xCo1+x(MoO4)3, and triple molybdate Na10(Cs4-xNax)Co5(MoO4)12 (0 ≤ x ≤ 0.30) were found, and their structures were solved. In the structure of Na3.21Cs0.37Co1.21(MoO4)3 (a = 13.0917(8) Å, b = 13.5443(8) Å, c = 7.1217(4) Å, space group C2/c, β = 112.331(2), Z = 4), the cesium ions partially substitute the Na+ in the channels running along the c-axis. The structure of Na10(Cs3.77Na0.23)Co5(MoO4)12 (a = 13.6572(3) Å, b = 11.5063(3) Å, c = 27.9898(5) Å, space group Pbca, Z = 4) was proved to be the aristotype for the pseudo orthorhombic Na25Cs8R5(MoO4)24 (R = Fe, Sc, In). The compounds contain alluaudite-like layers of MoO4 tetrahedra and pairs of edge-shared (Co, Na)O6 or (R, Na)O6 and NaO6 octahedra, which are connected by bridging MoO4 tetrahedra to form 3D frameworks differing from the alluaudite type. The frameworks contain channels along the c-axis filled by Cs+ and Na+ ions. Bond valence sum (BVS) maps show that the alluaudite-related molybdates can have a 2D sodium-ion conductivity at elevated temperatures in contrast to the alluaudite-type cathode material Na2+2xFe2-x(SO4)3 with a 1D conductivity. The measured ionic conductivity of Na4–2xCo1+x(MoO4)3, Na4–2x-yCsyCo1+x(MoO4)3, and Na10Cs4Co5(MoO4)12 reaches 10–3–10–2 S cm–1 at 500 °C.

AB - Phase formation study of the Na2MoO4–Cs2MoO4–CoMoO4 system resulted in new cesium-containing alluaudite-related phases. The solid solution Na4–2x-yCsyCo1+x(MoO4)3 (0 ≤ x, y ≤ 0.30), based on the alluaudite-type Na4–2xCo1+x(MoO4)3, and triple molybdate Na10(Cs4-xNax)Co5(MoO4)12 (0 ≤ x ≤ 0.30) were found, and their structures were solved. In the structure of Na3.21Cs0.37Co1.21(MoO4)3 (a = 13.0917(8) Å, b = 13.5443(8) Å, c = 7.1217(4) Å, space group C2/c, β = 112.331(2), Z = 4), the cesium ions partially substitute the Na+ in the channels running along the c-axis. The structure of Na10(Cs3.77Na0.23)Co5(MoO4)12 (a = 13.6572(3) Å, b = 11.5063(3) Å, c = 27.9898(5) Å, space group Pbca, Z = 4) was proved to be the aristotype for the pseudo orthorhombic Na25Cs8R5(MoO4)24 (R = Fe, Sc, In). The compounds contain alluaudite-like layers of MoO4 tetrahedra and pairs of edge-shared (Co, Na)O6 or (R, Na)O6 and NaO6 octahedra, which are connected by bridging MoO4 tetrahedra to form 3D frameworks differing from the alluaudite type. The frameworks contain channels along the c-axis filled by Cs+ and Na+ ions. Bond valence sum (BVS) maps show that the alluaudite-related molybdates can have a 2D sodium-ion conductivity at elevated temperatures in contrast to the alluaudite-type cathode material Na2+2xFe2-x(SO4)3 with a 1D conductivity. The measured ionic conductivity of Na4–2xCo1+x(MoO4)3, Na4–2x-yCsyCo1+x(MoO4)3, and Na10Cs4Co5(MoO4)12 reaches 10–3–10–2 S cm–1 at 500 °C.

KW - Conducting materials

KW - Molybdenum

KW - Phase diagrams

KW - Sodium

KW - Solid-state structures

KW - ELECTRICAL-PROPERTIES

KW - FUMAROLIC SUBLIMATE

KW - CRYSTAL-STRUCTURES

KW - IONIC-CONDUCTIVITY

KW - STRUCTURE CRISTALLINE

KW - CHEMISTRY

KW - DESCRIPTIVE MINERALOGY

KW - IZALCO VOLCANO

KW - EL-SALVADOR

KW - DOUBLE MOLYBDATES

UR - http://www.scopus.com/inward/record.url?scp=85059122519&partnerID=8YFLogxK

U2 - 10.1002/ejic.201801307

DO - 10.1002/ejic.201801307

M3 - Article

AN - SCOPUS:85059122519

VL - 2019

SP - 277

EP - 286

JO - European Journal of Inorganic Chemistry

JF - European Journal of Inorganic Chemistry

SN - 1434-1948

IS - 2

ER -