Sylvite
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern R050166
      Walker D, Verma P K, Cranswick L M D, Jones R L, Clark S M, Buhre S
      American Mineralogist 89 (2004) 204-210
      Halite-sylvite thermoelasticity
      Sample: msl515031, T = 25 C, P = 0.0 kbar, cell volume = 248.61 ang**3

      CELL PARAMETERS:   6.292188   6.292188   6.292188   90.00000   90.00000   90.00000
      SPACE GROUP: Fm3m
      X-RAY WAVELENGTH:     1.541838
               2-THETA      INTENSITY    D-SPACING   H   K   L
                28.38        100.00        3.1461    2   0   0
                40.55         63.49        2.2246    2   2   0
                50.22         19.50        1.8164    2   2   2
                58.67          8.08        1.5730    4   0   0
                66.42         20.12        1.4070    4   2   0
                73.74         13.71        1.2844    4   2   2
                87.69          3.96        1.1123    4   4   0
                87.69          3.96        1.1123    4   4   0
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.