COL  ICSD Collection Code 2059
 DATE Recorded Jan 1, 1980; updated Jun 26, 1998
 NAME Calcium sulfate dihydrate
 MINR Gypsum - from monte San Derato, Bologna, Italy
 FORM Ca (S O4) (H2 O)2
      = H4 Ca O6 S
 TITL A refinement of the crystal structure of gypsum Ca S O4 (H2 O)2
 REF  Acta Crystallographica B (24,1968-38,1982)
      ACBCA 30 (1974) 921-929
 AUT  Cole W F, Lancucki˙C˙J
 CELL a=5.670 b=15.201 c=6.533 ŕ=90.0 á=118.6 ç=90.0
      V=494.4 D=2.31 Z=4
 SGR  I 1 2/c 1     (15) - monoclinic
 CLAS 2/m   (Hermann-Mauguin) - C2h (Schoenflies)
 PRS  mI48
 ANX  ABX6
 PARM Atom__No OxStat  Wyck ---X--- ---Y--- ---Z---  -SOF-
      Ca     1  2.000    4e  1/2     0.0783  1/4
      S      1  6.000    4e  0.      0.0778  3/4
      O      1 -2.000    8f  0.9642  0.1327  0.5495
      O      2 -2.000    8f  0.7602  0.0221  0.6674
      O      3 -2.000    8f  0.3779  0.1826  0.4553
      H      1  1.000    8f  0.2447  0.1601  0.4974
      H      2  1.000    8f  0.3937  0.243   0.4896
 WYCK f3 e2
 ITF  Ca  1   B=1.72(25)
 ITF  S   1   B=1.40(36)
 ITF  O   1   B=1.67(17)
 ITF  O   2   B=1.94(18)
 ITF  O   3   B=2.5(2)
 ITF  H   1   B=4.05(33)
 ITF  H   2   B=3.98(35)
 REM  REF (refinement of earlier measured intensity data)
 REM  NDS (neutron diffraction from a single crystal)
 REM  B Space group given by author: I12/a1
 REM  M PDF 21-816, 33-311 (setting C2/c)
 RVAL 0.091
 TEST Calculated density unusual but tolerable. (Code 23)