Akermanite Diffraction data computed using the structure from the paper listed below, along with the cell parameters refined from the powder pattern for R061085 Yang H, Hazen R M, Downs R T, Finger L W Physics and Chemistry of Minerals 24 (1997) 510-519 Structural change associated with the incommensurate-normal phase transition in akermanite, Ca2MgSi2O7, at high pressure Sample: P = 0.0 GPa CELL PARAMETERS: 7.833800 7.833800 5.008200 90.00000 90.00000 90.00000 SPACE GROUP: P-42_1m X-RAY WAVELENGTH: 1.541838 2-THETA INTENSITY D-SPACING H K L 16.09 9.67 5.5093 1 1 0 17.68 1.76 5.0147 0 0 1 21.06 7.18 4.2168 1 0 1 22.82 2.84 3.8956 2 0 0 23.99 10.56 3.7085 1 1 1 25.56 4.05 3.4844 2 1 0 29.01 23.08 3.0764 2 0 1 31.24 100.00 2.8614 2 1 1 32.49 3.62 2.7546 2 2 0 35.79 1.72 2.5073 0 0 2 36.45 16.27 2.4638 3 1 0 37.22 5.12 2.4144 2 2 1 37.67 6.17 2.3868 1 0 2 39.04 7.01 2.3062 3 0 1 39.46 2.36 2.2821 1 1 2 40.78 1.54 2.2113 3 1 1 44.49 12.06 2.0352 2 1 2 45.69 2.30 1.9845 3 2 1 46.60 5.47 1.9478 4 0 0 48.12 6.22 1.8897 4 1 0 49.10 3.95 1.8542 2 2 2 49.61 9.81 1.8364 3 3 0 51.66 8.73 1.7683 4 1 1 52.00 18.58 1.7574 3 1 2 52.49 5.63 1.7422 4 2 0 53.07 2.96 1.7244 3 3 1 56.16 2.25 1.6369 3 2 2 57.59 1.69 1.5996 1 1 3 60.20 1.31 1.5361 2 0 3 61.49 4.25 1.5071 2 1 3 62.66 1.20 1.4815 3 3 2 63.62 2.52 1.4616 5 1 1 65.25 4.33 1.4290 2 2 3 66.47 2.39 1.4056 3 0 3 67.31 8.49 1.3901 5 2 1 68.02 2.72 1.3773 4 4 0 70.91 1.59 1.3281 4 4 1 71.20 1.29 1.3235 4 3 2 72.78 2.89 1.2985 6 0 0 75.87 1.07 1.2531 5 2 2 75.95 3.80 1.2520 4 1 3 75.83 1.06 1.2537 0 0 4 77.10 1.93 1.2362 3 3 3 80.17 1.69 1.1963 6 2 1 81.31 2.06 1.1825 5 4 1 81.58 1.03 1.1792 5 3 2 83.84 1.76 1.1531 6 0 2 85.04 1.27 1.1398 4 3 3 86.17 2.18 1.1278 5 1 3 86.05 1.17 1.1290 3 0 4 87.17 1.08 1.1173 3 1 4 89.53 1.07 1.0939 5 2 3 89.53 1.07 1.0939 5 2 3 XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.