COL  ICSD Collection Code 30791
 DATE Recorded Nov 6, 1984; updated Jan 19, 1999
 NAME Silicon oxide - carbon dioxide - nitrogen - methane (46/1.3/4.7/2)
 MINR Melanophlogite high - from Mt. Hamilton California, heated
 FORM (Si O2)46 (C O2)1.32 (N2)4.68 (C H4)2
      = C3.32 H8 N9.36 O94.64 Si46
 TITL Studies on clathrasils. III. Crystal structure of melanophlogite, 
      a natural clathrate compound of silica
 REF  Zeitschrift fuer Kristallographie (149,1979-)
      ZEKRD 164 (1983) 247-257
 AUT  Gies H
 CELL a=13.436 b=13.436 c=13.436 à=90.0 á=90.0 ç=90.0
      V=2425.5 D=2.00 Z=1
 SGR  P m -3 n      (223) - cubic
 CLAS m-3m  (Hermann-Mauguin) - Oh  (Schoenflies)
 PRS  cP161
 PARM Atom__No OxStat  Wyck ---X--- ---Y--- ---Z---  -SOF-
      Si     1  4.000   24k  0.      0.3098  0.1142
      Si     2  4.000   16i  0.1826  0.1826  0.1826
      Si     3  4.000    6c  0.25    0.      0.5
      O      1 -2.000   48l  0.0963  0.2465  0.136
      O      2 -2.000   24k  0.      0.4056  0.1813
      O      3 -2.000   12f  0.3423  0.      0.
      O      4 -2.000    8e  0.25    0.25    0.25
      N      1  0.000    6d  0.25    0.5     0.        0.78
      N      2  0.000    6d  5 Atoms not located in Unit Cell
      C      1  4.000    6d  0.25    0.5     0.        0.22
      O      5 -2.000    3 Atoms not located in Unit Cell
      CH4    2  4.000    2a  0.      0.      0.
      H      1 -1.000    2a  8 Atoms not located in Unit Cell
 WYCK l k2 i f e d2 c a2
ÿ
 TF   Atom   U(1,1)  U(2,2)  U(3,3)  U(1,2)  U(1,3)  U(2,3)
      Si 1    0.0259  0.0193  0.0198  0.0000  0.0000 -0.0020
      Si 2    0.0218  0.0218  0.0218 -0.0002 -0.0002 -0.0002
      Si 3    0.0127  0.0208  0.0208  0.0000  0.0000  0.0000
      O  1    0.0536  0.0673  0.0646  0.0322 -0.0125  0.0107
      O  2    0.1022  0.0368  0.0426  0.0000  0.0000 -0.0256
      O  3    0.0383  0.0164  0.0502  0.0000  0.0000  0.0000
      O  4    0.0736  0.0736  0.0736 -0.0269 -0.0269 -0.0269
      N  1    0.2430  1.0100  0.2430  0.0000  0.0000  0.0000
      C  1    0.2430  1.0100  0.2430  0.0000  0.0000  0.0000
      C  2    0.1740  0.1740  0.1740  0.0000  0.0000  0.0000
 REM  TEM 473
 REM  M PDF 25-7 (with a, b doubled), isostructural to cubic gas hydrate 
      I
 REM  M R(framework)=.082
 REM  M Zeolite structure type
 RVAL 0.061
 TEST Calculated density unusual but tolerable. (Code 23)
 TEST At least one temperature factor is implausible or meaningless but 
      agrees with the value given in the paper. (Code 52)