#54
Pcca
Example – Silver chlorite, AgClO2
Structures of lead chlorite, magnesium chlorite hexahydrate and silver chlorite
Okuda M, Ishihara M, Yamanaka M, Ohba S, Saito Y
Acta Crystallographica C46 (1990) 1755-1759
CIF
http://rruff.geo.arizona.edu/AMS/download.php?id=11349.cif&down=cif
The Fascination of Crystals and Symmetry 