CRYSTAL-GROWTH AND STRUCTURE OF THE ALUMOTHIOSILICATE MN1.84AL0.16SI0.84AL0.16S4

Single Crystals of the alumothiosilicate Mn1.84Al0.16Si0.84Al0.16S4 we re grown by chemical transport reaction. The compound represents the f irst example of this type of silicate. The crystals were characterized by electron microprobe analyses and X-ray methods. The compound cryst allizes in the olivine type structure, space group Pnma, a = 1 266.9(2 ), b = 739.6(3), c = 592.8(1) pm. The mean bond lengths are very simil ar to those in Mn2SiS4. That part of aluminum which is situated at the octahedral sites is not equally distributed amongst both types of oct ahedral positions but is enriched on the smaller and more symmetric M( 1) position.