Robertsite, Ca2MnIII3O2(PO4)3·3H2O

Robertsite, Ca2MnIII 3O2(PO4)3·3H2O

Robertsite, ideally Ca(2)Mn(3)O(2)(PO(4))(3)·3H(2)O [calcium manganese(III) tris-(orthophosphate) trihydrate], can be associated with the arseniosiderite structural group characterized by the general formula Ca(2)A(3)O(2)(TO(4))(3)·nH(2)O, with A = Fe, Mn; T = As, P; and n = 2 or 3. In this study, single-crystal X-ray diffraction data were used to determine the robertsite structure from a twinn...