Akermanite Diffraction data computed using the structute from the paper listed below, along with the cell parameters refined from single crystal data of R061091 Swainson I P, Dove M T, Schmahl W W, Putnis A Physics and Chemistry of Minerals 19 (1992) 185-195 Neutron powder diffraction study of the akermanite-gehlenite solid solution series Sample: 50% Ak CELL PARAMETERS: 7.7900 7.7900 5.0300 90.000 90.000 90.000 SPACE GROUP: P-42_1m ATOM X Y Z OCCUPANCY ISO(B) Ca 0.33690 0.16310 0.50930 1.000 4.404 Mg 0.00000 0.00000 0.00000 0.460 1.695 Al 0.00000 0.00000 0.00000 0.540 1.695 Al 0.14190 0.35810 0.94270 0.225 1.953 Si 0.14190 0.35810 0.94270 0.760 1.953 O 0.50000 0.00000 0.17820 1.000 4.120 O 0.14230 0.35770 0.26760 1.000 2.249 O 0.08500 0.17780 0.79800 1.000 4.884 X-RAY WAVELENGTH: 1.541838 BOUNDS ON TWO THETA: 0.0 90.0 LIMITS IMPOSED ON THE INDICES ARE: +/- 7 +/- 7 +/- 4 MAX. ABS. INTENSITY / VOLUME**2: 19.05954625 The INTENSITY cut off value is 1.00 2-THETA INTENSITY D-SPACING H K L 16.09 8.35 5.5084 1 1 0 17.63 2.89 5.0300 0 0 1 21.02 4.57 4.2257 1 0 1 22.83 1.96 3.8950 2 0 0 23.96 14.95 3.7144 1 1 1 25.57 3.95 3.4838 2 1 0 28.99 21.42 3.0796 2 0 1 31.23 100.00 2.8640 2 1 1 32.51 4.42 2.7542 2 2 0 35.70 2.44 2.5150 0 0 2 36.47 17.62 2.4634 3 1 0 37.22 6.93 2.4158 2 2 1 37.58 7.19 2.3934 1 0 2 39.04 7.27 2.3074 3 0 1 39.38 2.97 2.2878 1 1 2 40.79 1.28 2.2123 3 1 1 44.43 9.38 2.0392 2 1 2 45.70 2.13 1.9852 3 2 1 46.64 6.44 1.9475 4 0 0 48.16 3.26 1.8894 4 1 0 49.05 2.69 1.8572 2 2 2 49.65 7.80 1.8361 3 3 0 51.68 6.05 1.7687 4 1 1 51.96 17.16 1.7599 3 1 2 52.54 5.38 1.7419 4 2 0 53.10 2.16 1.7248 3 3 1 56.12 1.53 1.6389 3 2 2 57.45 1.62 1.6040 1 1 3 61.36 4.28 1.5108 2 1 3 63.66 1.69 1.4618 5 1 1 65.13 3.48 1.4322 2 2 3 65.14 1.12 1.4320 4 2 2 66.37 1.65 1.4086 3 0 3 67.36 6.68 1.3902 5 2 1 67.59 1.20 1.3861 3 1 3 68.09 2.63 1.3771 4 4 0 70.96 1.06 1.3282 4 4 1 72.85 2.32 1.2983 6 0 0 75.87 2.34 1.2541 4 1 3 81.38 1.15 1.1825 5 4 1 83.86 1.02 1.1537 6 0 2 86.11 1.56 1.1293 5 1 3 86.99 1.07 1.1200 3 1 4 ================================================================================ XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.