Pyroxene-ideal
Thompson R M, Downs R T
American Mineralogist 88 (2003) 653-666
Model pyroxenes I: Ideal pyroxene topologies
Pyroxene #15a based on stacking sequence ABABABCBABAC
Note: Atoms Mg, Si, and O are assigned to atomic positions just for convenience.
_database_code_amcsd 0003016
19.595917 6 3.4641016 90 90. 90 P2_1/c
atom    x   y   z
SiA  1/48 5/6 1/3
Mg1a 1/12 1/6   0
Mg2a 1/12   0 1/2
SiB  7/48 2/3 1/6
SiC  3/16 1/6 1/3
Mg1b  .25 2/3 5/6
Mg2b  .25   0 5/6
SiD  5/16 1/3 1/6
SiE 17/48 5/6   0
Mg1c 5/12 1/6   0
Mg2c 5/12   0 1/2
SiF 23/48 2/3 1/6
O1A 23/24 5/6 1/3
O2A  1/24   0 1/6
O3A  1/24 5/6 2/3
O1B  5/24 2/3 1/6
O2B   1/8   0 5/6
O3B   1/8 5/6 1/3
O1C   1/8 1/6 1/3
O2C  5/24   0 1/6
O3C  5/24 1/3 1/6
O1D   3/8 1/3 1/6
O2D  7/24   0 1/2
O3D  7/24 1/6   0
O1E  7/24 5/6   0
O2E   3/8   0 1/6
O3E   3/8 2/3 1/6
O1F 13/24 2/3 1/6
O2F 11/24   0 5/6
O3F 11/24 5/6 1/3