Protopyroxene
Yang H, Finger L W, Conrad P G, Prewitt C T, Hazen R M
American Mineralogist 84 (1999) 245-256
A new pyroxene structure at high pressure: Single-crystal X-ray and Raman study
of the Pbcn - P2_1cn phase transition in protopyroxene
Sample at P = 0.00 GPa, (Mg1.54Li.23Sc.23)Si2O6
_database_code_amcsd 0002092
9.2554 8.7650 5.3333 90 90 90 Pbcn
atom     x     y     z occ Biso
Mg1      0 .0983   .75 .77  .54
Sc1      0 .0983   .75 .23  .54
Mg2      0 .2644   .25 .77  .73
Li2      0 .2644   .25 .23  .73
Si   .2931 .0904 .0731      .49
O1A  .1189 .0920 .0799      .50
O2A  .3749 .2493 .0702      .79
O3A  .3499 .9816 .3023      .60