Silver-potassium cyclodecaphosphate decahydrate, Ag 4K 6P 10O 30 · 10H 2O: A new example of a phosphoric 10-member ring anion
Chemical preparation and atomic arrangement of Ag 4K 6P 10O 30 · 10H 2O are described. The title compound is triclinic, space group P overline1, with a = 14.267(7), b = 7.305(1), and c = 10.319(4) Å, α = 105.38(5)°, β = 101.03(5)°, γ = 87.51(5)°, and Z = 1. The main structural interests rest on the existence in the atomic arrangement of a rare type of phosphoric ring anion, (P 10O 30) 10-, and on an arrangement of Ag 4O 10 clusters in which silver atoms have a very unusual fourfold coordination. The phosphoric ring anion observed in the title compound is the first example of a centrosymmetrical (P 10O 30) 10- group. A comparison of the geometries of the three (P 10O 30) 10- presently known is given.