Garnet-type Mn3Cr2(GeO4)3

Abstract

Single crystals of garnet-type trimanganese(II) dichromium(III) tris[orthogermanate(IV)], MnII3CrIII2(GeO4)3, were obtained by utilizing a chemical transport reaction. Corresponding to the mineral garnet with the general formula AII3BIII2(SiO4)3, each of the four elements occupies only one crystallographically distinct position. Mn2+ occupies the respective A position (Wyckoff site 24c, site symmetry 2.22), being surrounded by eight O atoms that form a distorted cube [d(Mn—O) = 2.291 (2) and 2.422 (2) Å, 4× each], while Cr3+ on the B position (Wyckoff site 16a, site symmetry .-3.) is situated in a slightly distorted octahedron of six O2− anions [d(Cr—O) = 1.972 (2) Å, 6×]. In addition, the O atoms on general site 96h form isolated [GeO4]4− tetrahedra with Ge4+ on site 24d [site symmetry -4..; d(Ge—O) = 1.744 (2) Å, 4×].