Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1492744 | Materials Research Bulletin | 2006 | 7 Pages |
Abstract
According to thermal expansion data, O3-type phase NaxNi(1+x)/3Sb(2−x)/3O2 (x ≈ 0.8) undergoes at ca. 1270 K a reversible transition to a less dense form. The high-temperature phase quenched to liquid nitrogen belongs to P2 type, space group P63/mmc (no. 194), a = 3.0123 Å(2), c = 11.2264 Å(7) for x ≈ 0.74 at 298 K. The stabilisation of P2 versus O3-type structure at high temperatures seems to be due to alkali distribution over greater number of sites thus increasing entropy and decreasing Na+–Na+ repulsion.
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Authors
O.A. Smirnova, M. Avdeev, V.B. Nalbandyan, V.V. Kharton, F.M.B. Marques,