AM_Andyrobertsite Formula: As5 Cu5 (Ca.428 Cd.426 Mn.146) K O22 H6 Name: Andyrobertsite Unit cell: 9.8102 10.0424 9.9788 90.0 101.686 90.0 , V=962.71 Space group: P121/M1 (11)

Cooper M A , Hawthorne F C , The Canadian Mineralogist , 38 (2000) p.817-830, Highly undersaturated anions in the crystal structure of andyrobertsite -, calcio-andyrobertsite, a doubly acid arsenate of the form, K(Cd,Ca)[Cu5(AsO4)4{As(OH)2O2}](H2O)2