Arapovite Uvarova Y A, Sokolova E V, Hawthorne F C, Agakhanov A A, Pautov L A The Canadian Mineralogist 42 (2004) 1005-1011 The crystal structure of arapovite, U4+(Ca,Na)2(K1-x_x)[Si8O20],x~0.5, a new mineral species of the steacyite group from the Dara-i-Pioz moraine, Tien-Shan Mountains, Tajikistan Locality: Dara-i-Pioz moraine, Tien-Shan Mountains, Tajikistan _database_code_amcsd 0005955 7.5505 7.5505 14.7104 90 90 90 P4/mcc atom x y z occ Uiso U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) U4+A 0 0 .25 .59 .0097 .0071 .0071 .0149 0 0 0 ThA 0 0 .25 .26 .0097 .0071 .0071 .0149 0 0 0 CaA 0 0 .25 .10 .0097 .0071 .0071 .0149 0 0 0 DyA 0 0 .25 .02 .0097 .0071 .0071 .0149 0 0 0 SmA 0 0 .25 .01 .0097 .0071 .0071 .0149 0 0 0 PrA 0 0 .25 .01 .0097 .0071 .0071 .0149 0 0 0 CaB 0 .5 .25 .62 .0141 .0134 .0124 .0165 0 0 0 NaB 0 .5 .25 .34 .0141 .0134 .0124 .0165 0 0 0 NdB 0 .5 .25 .02 .0141 .0134 .0124 .0165 0 0 0 CeB 0 .5 .25 .01 .0141 .0134 .0124 .0165 0 0 0 BaB 0 .5 .25 .01 .0141 .0134 .0124 .0165 0 0 0 KC 0 0 0 .52 .0339 .0288 .0288 .0442 0 0 0 Si .2594 .3354 .10846 .0107 .0093 .0097 .0132 .0001 .0008 .0001 O1 -.2362 .6845 0 .0229 .0263 .0295 .0129 .0000 0 0 O2 .4538 .2567 .1361 .0172 .0105 .0191 .0221 .0005 .0004 .0036 O3 -.1026 .2508 .3357 .0157 .0130 .0138 .0202 -.0001 .0037 -.0026