Portlandite Diffraction data computed using the structure from the paper listed below, along with the cell parameters refined from the powder pattern for R070210 Henderson D M, Gutowsky H S American Mineralogist 47 (1962) 1231-1251 A nuclear magnetic resonance determination of the hydrogen positions in Ca(OH)2 T = 25 C CELL PARAMETERS: 3.593566 3.593566 4.909353 90.00000 90.00000 120.0000 SPACE GROUP: P-3m1 X-RAY WAVELENGTH: 1.541838 2-THETA INTENSITY D-SPACING H K L 18.08 64.74 4.9094 0 0 1 28.69 16.80 3.1121 1 0 0 34.11 2.37 2.6285 1 0 1 34.11 97.63 2.6285 0 1 1 47.15 17.93 1.9273 1 0 2 47.15 23.99 1.9273 0 1 2 50.80 27.61 1.7968 1 1 0 54.35 14.50 1.6873 1 1 1 56.19 1.18 1.6365 0 0 3 59.37 1.89 1.5561 2 0 0 62.60 9.84 1.4833 2 0 1 64.29 9.42 1.4484 1 0 3 64.29 1.16 1.4484 0 1 3 71.79 4.56 1.3142 2 0 2 71.79 3.37 1.3142 0 2 2 77.78 1.40 1.2273 0 0 4 79.12 2.01 1.2099 1 1 3 84.69 1.99 1.1439 1 2 1 84.88 1.16 1.1418 1 0 4 86.20 3.06 1.1276 0 2 3 86.20 3.06 1.1276 0 2 3 XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.