Pyroxene-ideal
Thompson R M, Downs R T
American Mineralogist 88 (2003) 653-666
Model pyroxenes I: Ideal pyroxene topologies
Pyroxene #29a based on stacking sequence ABABABACACBC
Note: Atoms Mg, Si, and O are assigned to atomic positions just for convenience.
_database_code_amcsd 0003036
19.595917 6 3.4641016 90 90. 90 Pc
atom     x     y   z
SiA   1/48  7/12 5/6
SiB   1/16 11/12 1/2
Mg1a   1/8  7/12 1/6
Mg2a   1/8   .25 1/6
SiC   3/16 11/12 5/6
SiD  11/48  7/12 1/2
Mg1b  7/24 11/12 1/6
Mg2b  7/24   .25 1/6
SiE  17/48  7/12 5/6
SiF  19/48 11/12 1/2
Mg1c 11/24  7/12 1/6
Mg2c 11/24   .25 1/6
SiG  25/48  1/12 2/3
SiH   9/16  5/12   0
Mg1d   5/8  1/12 1/3
Mg2d   5/8   .25 5/6
SiJ  11/16  7/12 1/6
SiK  35/48 11/12 1/2
Mg1e 19/24  7/12 1/2
Mg2e 19/24   .25 1/2
SiL  41/48 11/12 1/6
SiM  43/48  5/12 1/3
Mg1f 23/24 11/12 5/6
Mg2f 23/24   .25 5/6
O1A   1/12  7/12 5/6
O2A      0   3/4   0
O3A      0  5/12   0
O1B      0  1/12   0
O2B   1/12   .25 5/6
O3B   1/12  1/12 1/3
O1C    .25  1/12 1/3
O2C    1/6   .25 1/2
O3C    1/6  1/12   0
O1D    1/6  5/12   0
O2D    .25   .25 5/6
O3D    .25  5/12 1/3
O1E   5/12  5/12 1/3
O2E    1/3   .25 1/2
O3E    1/3  7/12 1/2
O1F    1/3  1/12   0
O2F   5/12   .25 5/6
O3F   5/12  1/12 1/3
O1G   7/12  1/12 2/3
O2G    1/2   .25 1/2
O3G    1/2  1/12   0
O1H    1/2  5/12   0
O2H   7/12   .25 1/6
O3H   7/12  7/12 1/6
O1J    3/4  5/12 2/3
O2J    2/3   .25 1/2
O3J    2/3  5/12   0
O1K    2/3  1/12   0
O2K    3/4   .25 1/6
O3K    3/4  1/12 2/3
O1L  11/12  1/12 2/3
O2L    5/6   .25 5/6
O3L    5/6  1/12 1/3
O1M    5/6  5/12 1/3
O2M  11/12   .25 1/6
O3M  11/12  7/12 1/6