Phase-X
Mancini F, Harlow G E, Cahill C L
American Mineralogist 87 (2002) 302-306
The crystal structure and cation ordering of phase-X -
(K1-x-n)2(Mg1-n[Al,Cr]n)2Si2O7H2x: A potential K- and H-bearing
phase in the mantle
_database_code_amcsd 0002757
5.028 5.028 13.216 90 90 120 P6_3cm
atom      x     y      z occ U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3)
Si1       0     0  .0127      .0102  .0102  .0065  .0051      0      0
Si2       0     0  .2602      .0069  .0069  .0001 .00345      0      0
MgM    -1/3   1/3  .1377 .92  .0080  .0080  .0137  .0040      0      0
AlM    -1/3   1/3  .1377 .03  .0080  .0080  .0137  .0040      0      0
CrM    -1/3   1/3  .1377 .01  .0080  .0080  .0137  .0040      0      0
K     .3532 .6453  .3875      .0153  .0239  .0082 -.0030  .0026 -.0001
O1    .3124     0  .2284      .0051  .0035  .0052 .00175  .0005      0
O2        0     0 -.1110      .0201  .0201  .0084 .01005      0      0
O3   -.3106     0  .0493      .0153  .0201  .0190 .01005 -.0004      0