Potassium tin(II) sulphate and related tin apatites: Mössbauer and X-ray studies
Abstract
Isolation of solid phases containing potassium, tin(II), and sulphate has been attempted from aqueous K–SnII–SO4 and K–SnII–SO4–X (X = F, Cl, Br, I, or NO3) systems. The only phases isolated were potassium tin(II) sulphate of composition ranging from K2Sn(SO4)2 to K2Sn2(SO4)3, and potassium tin(II) chloride- and bromide-sulphates, K3Sn2(SO4)3X. Single-crystal X-ray studies show the former to be essentially similar to the well known K2Pb(SO4)2, except for a marked tendency to form solid solutions with the simple SnII sulphate. The chloro- and bromo-compounds are shown to be closely similar to chlorapatites, with SO42– replacing PO43–. Mössbauer spectra of these phases are discussed in relation to the proposed structures.