Attempts to synthesize the hypothetical anhydrous fluoroperovskite NaCdF3, which has been predicted to be stable, resulted instead in a hydrated fluoride of nominal composition NaCdF(3)center dot 3H(2)O. It decomposes to sodium fluoride, cadmium fluoride, and water at 60 T. Its structure has been determined by single-crystal X-ray diffraction. Na(0.92(2))Cd(1.08)F(3.08)center dot 2.92H(2)O crystallizes in the cubic space group Fm (3) over barm with a = 8.2369(4) A 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. (c) 2006 Published by Elsevier Ltd.