Research output: Contribution to journal › Article › peer-review
New alluaudite-related triple molybdates Na25Cs8R5(MoO4)24 (R = Sc, In) : Synthesis, crystal structures and properties. / Savina, Aleksandra A.; Solodovnikov, Sergey F.; Belov, Dmitry A. et al.
In: New Journal of Chemistry, Vol. 41, No. 13, 07.07.2017, p. 5450-5457.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - New alluaudite-related triple molybdates Na25Cs8R5(MoO4)24 (R = Sc, In)
T2 - Synthesis, crystal structures and properties
AU - Savina, Aleksandra A.
AU - Solodovnikov, Sergey F.
AU - Belov, Dmitry A.
AU - Solodovnikova, Zoya A.
AU - Stefanovich, Sergey Yu
AU - Lazoryak, Bogdan I.
AU - Khaikina, Elena G.
PY - 2017/7/7
Y1 - 2017/7/7
N2 - New triple molybdates Na25Cs8R5(MoO4)24 (R = Sc, In) were prepared as powders and ceramics by solid state reactions, and their single crystals were also obtained from melts by spontaneous crystallization. The structures were determined by single crystal XRD analysis. The electrical conductivity of ceramics was measured by impedance spectroscopy. The crystal structures were determined in monoclinic sp. gr. P21/c, a = 14.0069(3) Å, b = 12.6498(3) Å, c = 28.6491(6) Å, β = 90.007(1)° (Sc) and a = 14.0062(2) Å, b = 12.6032(2) Å, c = 28.7138(4) Å, β = 90.001(1)° (In). Together with triclinic Na25Cs8Fe5(MoO4)24, the titled compounds form a distinctive family of pseudo-orthorhombic alluaudite-related structures with the parent sp. gr. Pbca. Its structural features are alluaudite-like polyhedral layers composed of pairs of edge-shared (R, Na)O6 and NaO6 octahedra connected by bridging MoO4 tetrahedra. The layers are joined together by means of interlayer MoO4 tetrahedra, thus forming open 3D frameworks with cavities filled with Cs+ and Na+ ions. The manner of stacking layers is somewhat different from the alluaudite type. The compounds undergo phase transitions at 668 (Sc) and 725 (In) K accompanied by an abrupt increase of electrical conductivity presumably Na+-ionic in nature. Above these transitions, the conductivity is as high as 10-3 S cm-1, which makes Na25Cs8R5(MoO4)24 (R = Sc, In) promising solid state electrolytes.
AB - New triple molybdates Na25Cs8R5(MoO4)24 (R = Sc, In) were prepared as powders and ceramics by solid state reactions, and their single crystals were also obtained from melts by spontaneous crystallization. The structures were determined by single crystal XRD analysis. The electrical conductivity of ceramics was measured by impedance spectroscopy. The crystal structures were determined in monoclinic sp. gr. P21/c, a = 14.0069(3) Å, b = 12.6498(3) Å, c = 28.6491(6) Å, β = 90.007(1)° (Sc) and a = 14.0062(2) Å, b = 12.6032(2) Å, c = 28.7138(4) Å, β = 90.001(1)° (In). Together with triclinic Na25Cs8Fe5(MoO4)24, the titled compounds form a distinctive family of pseudo-orthorhombic alluaudite-related structures with the parent sp. gr. Pbca. Its structural features are alluaudite-like polyhedral layers composed of pairs of edge-shared (R, Na)O6 and NaO6 octahedra connected by bridging MoO4 tetrahedra. The layers are joined together by means of interlayer MoO4 tetrahedra, thus forming open 3D frameworks with cavities filled with Cs+ and Na+ ions. The manner of stacking layers is somewhat different from the alluaudite type. The compounds undergo phase transitions at 668 (Sc) and 725 (In) K accompanied by an abrupt increase of electrical conductivity presumably Na+-ionic in nature. Above these transitions, the conductivity is as high as 10-3 S cm-1, which makes Na25Cs8R5(MoO4)24 (R = Sc, In) promising solid state electrolytes.
KW - NEGATIVE THERMAL-EXPANSION
KW - 1ST EXPERIMENTAL-EVIDENCE
KW - X-RAY-DIFFRACTION
KW - ELECTRICAL-PROPERTIES
KW - CESIUM MOLYBDATE
KW - PHOSPHATE
KW - SODIUM
KW - PHASE
KW - LITHIUM
KW - CONDUCTIVITY
UR - http://www.scopus.com/inward/record.url?scp=85021751594&partnerID=8YFLogxK
U2 - 10.1039/c7nj00202e
DO - 10.1039/c7nj00202e
M3 - Article
AN - SCOPUS:85021751594
VL - 41
SP - 5450
EP - 5457
JO - New Journal of Chemistry
JF - New Journal of Chemistry
SN - 1144-0546
IS - 13
ER -
ID: 10098166