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 sodium scandium px after Ohashi et al. (1994A)
with O3-O3-O3 angle = 173.7 and model oxygen radius = 1.328
_database_code_amcsd 0003499
9.929 9.189 5.305 90 109.8 90 C2/c
atom     x      y      z
Sc       0  11/12    1/4
Na       0    .25    1/4
Si   .3081   1/12  .2790
O1   .1339   1/12  .1683
O2   .3661    .25  .3317
O3   .3661  .0079  .0579