AM_Langbeinite Formula: K2 Ca2 S3 O12 Name: Langbeinite Unit cell: 10.4289 10.4289 10.4289 90.0 90.0 90.0 , V=1134.27 Space group: P213 (198)

Speer D , Salje E , Physics and Chemistry of Minerals , 13 (1986) p.17-24, Phase transitions in langbeinites I: Crystal chemistry, and structures of K-double sulfates of the langbeinite, type M2++K2(SO4)3, M++=Mg,Ni,Co,Zn,Ca, Sample: K2Ca2(SO4)3, T = 260 C