کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1492869 | 992421 | 2006 | 7 صفحه PDF | دانلود رایگان |
Attempts to synthesize the hypothetical anhydrous fluoroperovskite NaCdF3, which has been predicted to be stable, resulted instead in a hydrated fluoride of nominal composition NaCdF3·3H2O. It decomposes to sodium fluoride, cadmium fluoride, and water at 60 °C. Its structure has been determined by single-crystal X-ray diffraction. Na0.92(2)Cd1.08F3.08·2.92H2O crystallizes in the cubic space group Fm3¯m with a = 8.2369(4) Å and Z = 4. The structure is based on the NaSbF6-type (an ordered variant of the ReO3-type) and features tilted sodium- and cadmium-centred octahedra that are linked by shared vertices to form a three-dimensional network. Substitutional disorder occurs on the nonmetal site, which is occupied by both F and O atoms, and on one of the metal sites, which is occupied by 92% Na and 8% Cd. A four-fold orientational disorder of the tilted octahedra is manifested as partial occupancy (25%) of the nonmetal site. A scheme to synthesize the anhydrous fluoride is presented.
Journal: Materials Research Bulletin - Volume 41, Issue 3, 9 March 2006, Pages 667–673