title: Structure of caesium disulfate at 120 and 273 K.
abstract: The crystal structures of Cs2S2O7 at 120 and 273 K have been determined from X-ray single-crystal data. Caesium disulfate represents a new structure type with a uniquely high number of independent formula units at 120 K: In one part caesium ions form a tube surrounding the disulfate ions, [Cs8(S2O7)6+]n; in the other part a disulfate double-sheet sandwiches a zigzagging caesium ion chain, [Cs2(S2O7)6-]n. Caesium disulfate shows an isostructural order-disorder transition between 230 and 250 K, where two disulfate groups become partially disordered above 250 K. The Cs+-ion arrangement shows a remarkable similarity to the high-pressure Rb(IV) metal structure.
authors.affiliation: Technical University of Denmark, Department of Chemistry, DK-2800 Lyngby, Denmark. kenny@kemi.dtu.dk
authors.forename: Kenny
authors.initials: K
authors.lastname: Ståhl
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Berg
authors.forename: K Michael
authors.initials: KM
authors.lastname: Eriksen
authors.forename: Rasmus
authors.initials: R
authors.lastname: Fehrmann