Preparation, crystal structures and rapid hydration of P2- and P3-type sodium chromium antimony oxides
β Scribed by A.A. Pospelov; V.B. Nalbandyan
- Book ID
- 104030816
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 392 KB
- Volume
- 184
- Category
- Article
- ISSN
- 0022-4596
No coin nor oath required. For personal study only.
β¦ Synopsis
Two new Na x [Cr (1 ΓΎ x)/2 Sb (1 Γ x)/2 ]O 2 compounds have been prepared by solid-state reactions in argon. Their structures have been determined by the X-ray Rietveld method. Both new phases together with NaCrO 2 -based solid solution comprise brucite-like layers of edge-shared (Cr,Sb)O 6 octahedra but differ by packing mode of the layers and coordination of the interlayer Na ΓΎ ions. A P3 phase exists at x E 0.5-0.58. It is rhombohedral (R3 Β―m), a ΒΌ 2.966, c ΒΌ 16.937 Γ at x E 0.58, with 29% Na ΓΎ occupancy of trigonal prisms. A P2 phase exists at x E0.6-0.7. It is hexagonal (P6 3 /mmc), a ΒΌ 2.960, c ΒΌ 11.190 Γ at x E 0.7, with 37% and 33% Na ΓΎ occupancy of two non-equivalent trigonal prisms. Both P2 and P3 phases rapidly absorb moisture in air; packing mode is preserved, the a parameter changes slightly but c increases by 24-25%. Very high sodium ion conductivity is predicted for both P2 and P3 anhydrous phases.
π SIMILAR VOLUMES