Original paper

Solid solution series of silico - sulphate - chloride - apatites

Neubauer, J.; Pöllmann, H.

Abstract

Ellestadites X10[(SiO4)3/(SO4)3/Cl2] with X = Ca, Pb and Sr are forming perfect solid solution series with each other. Ca10[(SiO4)3/(SO4)3/Cl2] forms partial solid solutions to Ca10[(SiO4)4/(SO4)2], a compound with silico-carnotite structure. Pb and Sr analogues to Ca10[(SiO4)4/(SO4)2] do not exist, but Pb10[(SiO4)3/(SO4)3/Cl2] forms partial solid solutions to the hypothetical end member. In the case of Sr10 [(SiO4)3/(SO4)3/Cl2] no exchange of SO42- and 2Cl- by SiO44- takes place. Perfect solid solution occurs in the systems Ca10[(SiO4)3/(SO4)3/Cl2]-Ca10[(PO4)6/Cl2] and Ca10[(SiO4)3/(SO4)3/Cl2]-Ca10[(CrO4)6/Cl2].

Keywords

Ellestadite • silico-carnotite • heavy metal • Inner Barrier • chloride