#143
P3
Example – Simpsonite, Ta3Al4O13(OH)
Named for Edward Sydney Simpson (1875-1939), Western Australian government mineralogis and mineral analyst.
The crystal chemistry of Simpsonite
Ercit T S, Cerny P, Hawthorne F C
The Canadian Mineralogist 30 (1992) 663-671
http://www.webmineral.com/data/Simpsonite.shtml
CIF
http://rruff.geo.arizona.edu/AMS/download.php?id=05775.cif&down=cif
TaO6 octahedra (brown)
AlO6 octahedra (blue)
The Fascination of Crystals and Symmetry 