Stibarsen
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from single crystal data of R060115
      Bayless P
      American Mineralogist 76 (1991) 257-265
      Crystal chemistry and crystallography of some minerals in the tetradymite group

      CELL PARAMETERS:   4.0530  4.0530 10.8500   90.000   90.000  120.000
      SPACE GROUP: R-3m      

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            As     0.00000   0.00000   0.00000     1.000     0.600
            Sb     0.00000   0.00000   0.50000     1.000     1.000

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    0.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  3 +/-  3 +/-  9
            MAX. ABS. INTENSITY / VOLUME**2:      281.6183562    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                24.61          2.64        3.6167    0   0   3
                26.69          6.41        3.3396    1   0   1
                30.33        100.00        2.9470    0   1   2
                42.10         38.78        2.1463    1   0   4
                44.72         32.19        2.0265    1   1   0
                50.47          7.30        1.8083    0   0   6
                51.71          1.68        1.7679    1   1   3
                54.99         16.50        1.6698    2   0   2
                63.09         10.37        1.4735    0   2   4
                69.69         14.81        1.3492    1   1   6
                73.49         12.42        1.2887    1   2   2
                75.09          5.79        1.2651    0   1   8
                80.61          9.28        1.1918    2   1   4
                82.43          4.34        1.1700    3   0   0
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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.