AM_As2O(SO4)2_1
Formula: As2 S2 O9
Name: As2O(SO4)2
Unit cell: 6.65 6.671 16.612 90.0 94.34 90.0 , V=734.83
Space group: P121/C1 (14)

Marsh R E , Herbstein F H , Acta Crystallographica, Section B , 44 (1988) p.77-88, More space-group changes