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 with O3-O3-O3 angle = 180 and model oxygen radius = 1
Note: Atoms Mg, Si, and O are assigned to atomic positions for convenience
_database_code_amcsd 0003474
7.526 6.928 4 90 110.8 90 C2/c
atom     x      y      z
Mg1      0  11/12    1/4
Mg2      0    .25    1/4
Si   .3080   1/12  .2887
O1   .1340   1/12  .1726
O2   .3660    .25  .3274
O3   .3660      0  .0774