Akermanite
Yang H, Hazen R M, Downs R T, Finger L W
Physics and Chemistry of Minerals 24 (1997) 510-519
Structural change associated with the incommensurate-normal phase transition
in akermanite, Ca2MgSi2O7, at high pressure
Sample: P = 2.78 GPa
Note: O2-z changed to match reported bond lengths
_database_code_amcsd 0008035
7.7677 7.7677 4.9495 90 90 90 P-42_1m
atom     x     y     z Biso B(1,1) B(2,2) B(3,3) B(1,2) B(1,3) B(2,3)
Ca   .3336 .1664 .5050 1.15  .0048  .0048  .0113  .0017  .0007  .0007
Mg       0     0     0  .81  .0020  .0020  .0147      0      0      0
Si   .1405 .3595 .9348  .66  .0029  .0029  .0061  .0003 -.0001 -.0001
O1      .5     0 .1837  1.4  .0077  .0077  .0050 -.0046      0      0
O2   .1399 .3601 .2584  1.5  .0058  .0058  .0168  .0005 -.0023 -.0023
O3   .0820 .1848 .7799  1.3  .0070  .0035  .0127 -.0008  .0027 -.0019