#155
R32
Example – Tincalconite, Na6[B4O5(OH)4]3 • 8 H2O
Named for tincal (borax) and konos “powder” in allusion to the minerals composition and appearance.
The crystal structure of Tincalconite
Giacovazzo C, Menchetti S, Scordari F
American Mineralogist 58 (1973) 523-530
CIF
http://rruff.geo.arizona.edu/AMS/download.php?id=00394.cif&down=cif
BO3 trigonal-planar units and BO4 tetrehedra (pink)
NaO6 distorted octahedra (orange)
Water partially disordered.
The Fascination of Crystals and Symmetry 