issue contents
January 2004 issue
editorial
Free
international union of crystallography
Free
inorganic compounds
The title compound belongs to the apatite family and crystallizes with anionic vacancies in tunnels.
(NH4)4Cd(HSeIVO3)2(SeVIO4)2 contains kröhnkite-like chains in which CdO6 octahedra are linked via bridging HSeO3 groups. SeO4 groups, which decorate the chains, are attached to the CdO6 octahedra in a trans arrangement.
The hexagonal crystal structure of UCoAl4 consists of a succession of atomic layers of composition UCoAl and Al3 alternating along the short c axis.
The title compound is isostructural with K2[FeF5(H2O)] and contains polymeric anion chains held together by strong O—H⋯F bonds. Each V atom is coordinated to five terminal F atoms and the O atom of one water molecule. Pairs of O—H⋯F bonds are formed by two cis-related F atoms. Twofold axes run along the O—V—F axis of the V-centred octahedra.