Brucite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from the powder pattern of R040077
      Catti M, Ferraris G, Hull S, Pavese A
      Physics and Chemistry of Minerals 22 (1995) 200-206
      Static compression and H disorder in brucite, Mg(OH)2, to 11 GPa:
      a powder neutron diffraction study
      Sample: at P = 0.0001 GPa

      CELL PARAMETERS:   3.1467  3.1467  4.7679   90.000   90.000  120.000
      SPACE GROUP: P-3m1     

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Mg     0.00000   0.00000   0.00000     1.000     0.430
            O      0.33333   0.66667   0.22030     1.000     0.420
            H      0.33333   0.66667   0.41300     1.000     2.475

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  2 +/-  2 +/-  4
            MAX. ABS. INTENSITY / VOLUME**2:      17.30924469    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                18.61         69.09        4.7679    0   0   1
                32.87          2.93        2.7251    1   0   0
                38.03         99.07        2.3659    0   1   1
                50.89         14.09        1.7943    1   0   2
                50.89         32.27        1.7943    0   1   2
                58.68         27.10        1.5733    1   1   0
                62.13         13.21        1.4941    1   1   1
                68.32         13.83        1.3729    1   0   3
                68.32          1.11        1.3729    0   1   3
                72.09          9.34        1.3101    2   0   1
                80.60          1.93        1.1920    0   0   4
                81.34          2.65        1.1830    0   2   2
                81.34          5.85        1.1830    2   0   2
                89.81          2.24        1.0921    1   0   4
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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.