Periclase
      Jacobsen S D, Holl C M, Adams K A, Fischer R A, Martin E S, Bina C R, Lin J F,
      Prakapenka V B, Kubo A, Dera P
      American Mineralogist 93 (2008) 1823-1828
      Compression of single-crystal magnesium oxide to 118 GPa and a ruby pressure
      gauge for helium pressure media
      Note: P = 18.2 GPa using ruby-scale
      Note: P = 18.5 GPa using MgO-scale
      _database_code_amcsd 0004685

      CELL PARAMETERS:    4.0800   4.0800   4.0800   90.000   90.000   90.000
      SPACE GROUP: Fm3m      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:     67.917
      Density (g/cm3):      3.941
      MAX. ABS. INTENSITY / VOLUME**2:      36.34499751    
      RIR:      3.003
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                38.21         11.61        2.3556    1   1   1         8
                44.41        100.00        2.0400    2   0   0         6
                64.61         49.20        1.4425    2   2   0        12
                77.61          6.37        1.2302    3   1   1        24
                81.77         13.34        1.1778    2   2   2         8
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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.