Pyroxene-ideal
Thompson R M, Downs R T
American Mineralogist 88 (2003) 653-666
Model pyroxenes I: Ideal pyroxene topologies
Pyroxene #24 based on stacking sequence ABACBCABACBC
Note: Atoms Mg, Si, and O are assigned to atomic positions just for convenience.
_database_code_amcsd 0003031
19.899748 6 3.4641016 90 100.024987862 90 C2/c
atom    x    y     z
Mg1a    0 5/12   3/4
Mg2a    0  .25   1/4
SiA  1/16 1/12 13/16
SiB  5/48 5/12 25/48
Mg1b  1/6 1/12   1/4
Mg2b  1/6  .25   3/4
SiC 11/48 5/12  5/16
O1A   1/8 1/12   7/8
O2A  1/24  .25 23/24
O3A  1/24 1/12 11/24
O1B  1/24 5/12 11/24
O2B   1/8  .25   3/8
O3B   1/8 7/12   3/8
O1C  7/24 5/12   3/8
O2C  5/24  3/4   5/8
O3C  5/24 5/12   5/8