title: SrNp(PO4)2: an original ordered modification of cheralite.
abstract: The new compound SrNp(PO(4))(2) (orthorhombic Cmca) has been synthesized by a solid-state reaction and its crystal structure solved ab initio and refined by Rietveld analysis. Though chemically and structurally related to the cheralite CaTh(PO(4))(2), SrNp(PO(4))(2) shows alternate layers of SrO(10) and NpO(8) polyhedra instead of a disordered array of 9-fold polyhedra. Raman and IR spectroscopic measurements also account for ordered cations. This novel structural type allows one to explain the boundaries of the cheralite domain in terms of the cation size and can be proposed as an archetype for a series of other actinide-bearing phosphate compounds.
authors.affiliation: Department of Chemistry, Al. I. Cuza University, 11 Carol I Boulevard, 700506 Iasi, Romania.
authors.forename: Karin
authors.initials: K
authors.lastname: Popa
authors.forename: Gilles
authors.initials: G
authors.lastname: Wallez
authors.forename: Philippe E
authors.initials: PE
authors.lastname: Raison
authors.forename: Damien
authors.initials: D
authors.lastname: Bregiroux
authors.forename: Christos
authors.initials: C
authors.lastname: Apostolidis
authors.forename: Patric
authors.initials: P
authors.lastname: Lindqvist-Reis
authors.forename: Rudy J M
authors.initials: RJ
authors.lastname: Konings