Cuprostibite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from the powder pattern of R060838
      Pearson W B
      Zeitschrift fur Kristallographie 171 (1985) 23-39
      The Cu2Sb and related structures

      CELL PARAMETERS:   3.9970  3.9970  6.0940   90.000   90.000   90.000
      SPACE GROUP: P4/nmm    

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Cu     0.00000   0.00000   0.00000     1.000     0.700
            Sb     0.50000   0.00000   0.70000     1.000     1.000
            Cu     0.50000   0.00000   0.27000     1.000     0.700

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    0.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  3 +/-  3 +/-  5
            MAX. ABS. INTENSITY / VOLUME**2:      202.0355134    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                14.54          4.35        6.0940    0   0   1
                26.67         15.26        3.3422    1   0   1
                29.31         13.11        3.0470    0   0   2
                31.66         33.93        2.8263    1   1   0
                35.00         47.40        2.5640    1   1   1
                37.10          8.46        2.4232    1   0   2
                43.68        100.00        2.0721    1   1   2
                44.61         15.79        2.0313    0   0   3
                45.38         54.30        1.9985    2   0   0
                53.42          3.91        1.7152    2   1   1
                54.94          7.76        1.6711    2   0   2
                55.73          2.34        1.6495    1   1   3
                60.00          3.64        1.5418    2   1   2
                60.80          4.19        1.5235    0   0   4
                65.52         17.04        1.4246    2   0   3
                65.58          3.08        1.4236    1   0   4
                66.12         14.97        1.4132    2   2   0
                73.93          2.80        1.2820    2   2   2
                75.17          4.23        1.2640    3   1   0
                77.06          6.92        1.2376    3   1   1
                79.03          6.68        1.2116    2   0   4
                82.65         22.91        1.1675    3   1   2
                83.30          7.60        1.1601    2   2   3
                83.35          2.85        1.1595    2   1   4
                87.08          9.63        1.1192    1   1   5
================================================================================
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.