Nonstoichiometry in the systems Na2MoO4–MMoO4 (M = Co, Cd), crystal structures of Na3.36Co1.32(MoO4)3, Na3.13Mn1.43(MoO4)3 and Na3.72Cd1.14(MoO4)3, crystal chemistry, compositions and ionic conductivity of alluaudite-type double molybdates and tungstates
| Autor: | Sergey F. Solodovnikov, Zoya A. Solodovnikova, B. M. Kuchumov, E. S. Zolotova, Yunna L. Tushinova, Oksana A. Gulyaeva, Vasiliy N. Yudin |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Chemistry
Crystal chemistry Inorganic chemistry chemistry.chemical_element 02 engineering and technology Manganese Crystal structure Triclinic crystal system 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Electronic Optical and Magnetic Materials Inorganic Chemistry Crystallography Materials Chemistry Ceramics and Composites Ionic conductivity Orthorhombic crystal system Physical and Theoretical Chemistry 0210 nano-technology Cobalt Monoclinic crystal system |
| Zdroj: | Journal of Solid State Chemistry. 253:121-128 |
| ISSN: | 0022-4596 |
| Popis: | As results of a powder XRD study of sintered samples of the systems Na2MoO4–MMoO4 (M = Co, Cd) quenched in air from 873 K, the literature data on the phase formation and homogeneity ranges of nonstoichiometric double molybdates in these systems were corrected. The compounds are monoclinic alluaudite-type Na4-2xCo1+x(MoO4)3 (0.05 ≤ x ≤ 0.30) and Na4-2xCd1+x(MoO4)3 (0.10 ≤ x ≤ 0.40), orthorhombic lyonsite-type Na2-2yCo2+y(MoO4)3 (0.05 ≤ y ≤ 0.25), and triclinic Na2-2zCo2+z(MoO4)3 (0.10 ≤ z ≤ 0.40) of the Na2Mg5(MoO4)6 type. The temperature of the orthorhombic-to-triclinic phase transition was found to be 943 ± 10 K. Crystal structures of the alluaudite-type double molybdates (space group C2/c, Z = 4) with cobalt, manganese, and cadmium were determined. According to the atomic position occupations, the compositions for the crystals were found as Na3.36Co1.32(MoO4)3 (a = 12.6381(3), b = 13.4888(4), c = 7.1244(2) A, β = 112.127(1)°, R = 0.0207), Na3.13Mn1.43(MoO4)3 (a = 12.7387(3), b = 13.6716(4), c = 7.1904(2) A, β = 112.404(1)°, R = 0.0166), and Na3.72Cd1.14(MoO4)3 (a = 12.804(3), b = 13.913(3), c = 7.326(2) A, β = 112.63(1)°, R = 0.0158). The crystal chemistry and compositions of the alluaudite-type molybdates and tungstates were considered and mainly one-dimensional character of the sodium-ion transport was shown for them. The measured values of the ionic conductivity of sintered samples of Na3.6M1.2(MoO4)3 (M = Mg, Ni, Zn, Cd) and Na3.6Mg1.2(WO4)3 exceeds 10−3 S cm−1 at 673 K. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect