Cristobalite
      Matsui M, Sato T, Funamori N
      American Mineralogist 99 (2014) 184-189
      Crystal structures and stabilities of cristobalite-helium phases at high pressures
      Note: P = 4 GPa
      Locality: calculated structure
      _database_code_amcsd 0020171

      CELL PARAMETERS:    9.0800   9.0800   9.0800   31.809   31.809   31.809
      SPACE GROUP: R-3c      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    184.735
      Density (g/cm3):      2.304
      MAX. ABS. INTENSITY / VOLUME**2:      23.47863984    
      RIR:      3.318
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                20.62         42.59        4.3067    2   2   2         2
                21.74        100.00        4.0883    1   1   0         6
                34.71         22.43        2.5847    3   3   2         6
                36.10         21.71        2.4882    0  -1   1         6
                37.63         12.64        2.3905    2   1   0        12
                42.53          2.63        2.1255    2   0   0         6
                44.31          4.38        2.0442    2   2   0         6
                56.98          7.71        1.6161    2  -1   1        12
                64.91          8.73        1.4366    1  -2   1         6
                68.90          1.42        1.3628    3   3   0         6
                76.58          2.79        1.2441    0  -2   2         6
                80.74          3.70        1.1902    0  -1   3        12
================================================================================
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.