Silicon
      Olijnyk H, Sikka S K, Holzapfel W B
      Physics Letters 103A (1984) 137-140
      Structural phase transitions in Si and Ge under pressures up to 50 GPa
      Locality: synthetic
      Sample: at P = 19.5 GPa
      Note: phase V, structure stable between 16 GPa & 34 GPa
      _database_code_amcsd 0015303

      CELL PARAMETERS:    2.5270   2.5270   2.3730   90.000   90.000  120.000
      SPACE GROUP: P6/mmm    
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:     13.123
      Density (g/cm3):      3.553
      MAX. ABS. INTENSITY / VOLUME**2:      37.58201849    
      RIR:      3.444
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                37.92         43.18        2.3730    0   0   1         2
                41.25        100.00        2.1884    1   0   0         6
                57.27         70.97        1.6088    1   0   1        12
                75.20         15.02        1.2635    1   1   0         6
                81.04          4.04        1.1865    0   0   2         2
                87.46         19.96        1.1153    1   1   1        12
                89.58          9.45        1.0942    2   0   0         6
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       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.