Simpsonite Diffraction data computed using the structure from the paper listed below, along with the cell parameters refined from single crystal data of R061059 Ercit T S, Cerny P, Hawthorne F C The Canadian Mineralogist 30 (1992) 663-671 The crystal chemistry of simpsonite CELL PARAMETERS: 7.3820 7.3820 4.5120 90.000 90.000 120.000 SPACE GROUP: P3 ATOM X Y Z OCCUPANCY ISO(B) Ta 0.11180 0.39100 0.00000 1.000 0.773 Al 0.42300 0.30300 0.49600 1.000 1.103 Al 0.00000 0.00000 0.49900 1.000 1.029 O 0.24600 0.06200 0.73000 1.000 1.105 O 0.39200 0.47200 0.77700 1.000 1.914 O 0.19200 0.23800 0.27400 1.000 1.257 O 0.48200 0.11100 0.26500 1.000 1.795 O 0.33333 0.66667 0.19400 1.000 0.638 OH 0.66667 0.33333 0.69100 1.000 2.742 X-RAY WAVELENGTH: 1.541838 BOUNDS ON TWO THETA: 0.0 90.0 LIMITS IMPOSED ON THE INDICES ARE: +/- 5 +/- 5 +/- 4 MAX. ABS. INTENSITY / VOLUME**2: 120.8927237 The INTENSITY cut off value is 1.00 2-THETA INTENSITY D-SPACING H K L 13.85 42.58 6.3930 1 0 0 19.68 57.26 4.5120 0 0 1 24.11 59.86 3.6910 1 1 0 24.14 34.42 3.6864 0 1 1 24.14 33.82 3.6864 1 0 1 27.91 29.67 3.1965 2 0 0 31.31 48.45 2.8569 2 -1 1 31.31 51.55 2.8569 1 1 1 34.38 28.73 2.6083 0 2 1 34.38 26.86 2.6083 2 0 1 37.21 45.21 2.4163 1 2 0 37.21 5.34 2.4163 2 1 0 39.96 10.88 2.2560 0 0 2 42.42 4.44 2.1310 3 0 0 42.44 6.14 2.1301 -1 3 1 42.44 6.20 2.1301 3 -1 1 42.44 43.02 2.1301 1 2 1 42.44 5.92 2.1301 2 1 1 42.49 3.51 2.1274 0 1 2 42.49 3.19 2.1274 1 0 2 47.17 3.45 1.9269 0 3 1 47.17 3.30 1.9269 3 0 1 47.22 11.86 1.9249 1 1 2 47.22 8.41 1.9249 2 -1 2 49.45 7.72 1.8432 0 2 2 49.45 5.74 1.8432 2 0 2 51.54 15.01 1.7731 3 1 0 51.54 2.40 1.7731 1 3 0 55.70 15.98 1.6502 -1 4 1 55.70 1.61 1.6502 4 -1 1 55.70 16.34 1.6502 3 1 1 55.70 1.37 1.6502 1 3 1 55.75 1.35 1.6490 -1 3 2 55.75 26.90 1.6490 3 -1 2 55.75 24.92 1.6490 1 2 2 55.75 1.83 1.6490 2 1 2 57.68 4.51 1.5982 4 0 0 59.69 1.68 1.5492 0 3 2 59.69 1.52 1.5492 3 0 2 61.56 5.99 1.5065 0 4 1 61.56 5.90 1.5065 4 0 1 61.67 3.05 1.5040 0 0 3 63.42 1.19 1.4667 3 2 0 63.42 7.19 1.4667 2 3 0 63.55 1.29 1.4640 0 1 3 63.55 1.37 1.4640 1 0 3 67.09 3.20 1.3951 1 4 0 67.09 12.20 1.3951 4 1 0 67.11 1.64 1.3948 -2 5 1 67.11 8.12 1.3948 2 3 1 67.11 8.94 1.3948 5 -2 1 67.11 1.55 1.3948 3 2 1 67.15 1.10 1.3941 4 -1 2 67.15 5.76 1.3941 3 1 2 67.15 5.61 1.3941 -1 4 2 67.21 5.19 1.3928 1 1 3 67.21 5.53 1.3928 2 -1 3 69.01 3.88 1.3609 0 2 3 69.01 3.80 1.3609 2 0 3 70.68 2.16 1.3328 -1 5 1 70.68 3.90 1.3328 1 4 1 70.68 4.33 1.3328 5 -1 1 70.68 2.16 1.3328 4 1 1 72.47 2.03 1.3041 4 0 2 72.47 2.09 1.3041 0 4 2 74.28 1.17 1.2769 -1 3 3 74.28 5.51 1.2769 3 -1 3 74.28 1.81 1.2769 1 2 3 74.28 1.40 1.2769 2 1 3 77.65 4.29 1.2296 5 -2 2 77.65 3.87 1.2296 2 3 2 81.04 2.12 1.1865 -1 5 2 81.04 2.08 1.1865 5 -1 2 81.04 1.65 1.1865 1 4 2 81.04 2.12 1.1865 4 1 2 84.47 3.81 1.1470 -1 4 3 84.47 3.69 1.1470 3 1 3 86.23 2.74 1.1280 0 0 4 89.47 1.61 1.0953 4 0 3 89.47 1.59 1.0953 0 4 3 ================================================================================ XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.