Weberite Knop O, Cameron T S, Jochem K Journal of Solid State Chemistry 43 (1982) 213-221 What is the true space group of weberite? Locality: Ivigtut, Greenland Sample: I2mb refinement, T = 133 K Note: z(F6) corrected _database_code_amcsd 0013484 7.051 9.968 7.285 90 90 90 *I2mb 0 .25 .25 atom x y z U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) Na1 .2536 0 .4958 .0121 .0122 .0432 0 -.0033 0 Na2 0 .25 .75 .0142 .0253 .0123 0 0 .0070 Mg .2520 0 .9992 .0052 .0047 .0078 0 .0005 0 Al .0014 .25 .25 .0053 .0052 .0078 0 0 -.0012 F1 .0013 0 .8862 .0054 .0140 .0118 0 .0013 0 F3 .0023 .1644 .4713 .0127 .0111 .0100 -.0012 -.0010 .0000 F5 .1875 .1382 .1822 .0087 .0088 .0134 .0002 -.0001 -.0030 F6 .3185 .1367 .8209 .0095 .0095 .0154 .0041 .003 -.0045