title: [P(3)Se(7)](3-): a phosphorus-rich square-ring selenophosphate.
abstract: The new compound Cs(10)P(8)Se(20) features the heterotetracyclic [P(3)Se(7)](3-) anion, a phosphorus-rich four-membered-ring species that possesses a P-P-P unit and formally P(3+) and P(4+) centers. It crystallizes in the orthorhombic space group Pnnm with a = 26.5456(7) A, b = 8.0254(2) A, c = 11.9031(4) A, and Z = 2 at 100(2) K. The cyclic anion is cocrystallized with a [P(2)Se(6)](4-) anion. Electronic absorption, Raman, Fourier transform infrared, and solid-state (31)P NMR spectroscopy studies of Cs(10)P(8)Se(20) are reported.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: In
authors.initials: I
authors.lastname: Chung
authors.forename: Daniel
authors.initials: D
authors.lastname: Holmes
authors.forename: David P
authors.initials: DP
authors.lastname: Weliky
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis