Abstract
The crystal structure of goyazite has been re-refined using the counter data, giving R=0.039 for 417 reflections. Formula: SrAl3 (OH)6 [PO3(O1⁄2(OH)1⁄2)]2. Cell dimensions: a=7.015(3), c=16.558(6)Å, space group R-3m, Z=3. Goyazite has a structure analogous with that of alunite and/or crandallite. Either apical O of a pair of P tetra-hedra is replaced by OH. Mean distances of M–(O, OH) are as follows: P–(O, OH) 1.535Å, Al–(O, OH) 1.896Å, Sr–(O, OH) 2.748Å.
