Pyroxene-ideal
Thompson R M, Downs R T
American Mineralogist 89 (2004) 614-628
Model pyroxenes II: Structural variation as a function of tetrahedral rotation
model zinc px after Morimoto et al. (1975)
with O3-O3-O3 angle = 161.3 and model oxygen radius = 1.329
_database_code_amcsd 0003507
9.755 9.083 5.244 90 107.9 90 C2/c
atom     x      y      z
Zn       0  11/12    1/4
Zn       0    .25    1/4
Si   .3084   1/12  .2596
O1   .1331   1/12  .1594
O2   .3669    .25  .3406
O3   .3669  .0238  .0193