data_global _chemical_name_mineral 'Perkovaite' loop_ _publ_author_name 'Krivovichev S V' 'Shcherbakova E P' 'Nishanbaev T P' _journal_name_full 'The Canadian Mineralogist' _journal_volume 48 _journal_year 2010 _journal_page_first 1469 _journal_page_last 1475 _publ_section_title ; The crystal structure of beta-CaMg2(SO4)3, a mineral phase from coal dumps of the Chelyabinsk coal basin, Russia ; _database_code_amcsd 0018301 _chemical_compound_source 'coal dumps of the Chelyabinsk coal basin, Russia' _chemical_formula_sum 'S6 Mg4 Ca3 O24' _cell_length_a 16.581 _cell_length_b 16.581 _cell_length_c 7.348 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 1749.529 _exptl_crystal_density_diffrn 3.014 _symmetry_space_group_name_H-M 'P 63' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x-y,x,1/2+z' '-y,x-y,z' '-x,-y,1/2+z' '-x+y,-x,z' 'y,-x+y,1/2+z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv S1 0.33636 0.31945 0.22590 0.01280 S2 0.16348 0.18021 -0.28250 0.01520 S3 0.31904 0.48329 0.71240 0.01310 S4 0.51650 0.33590 0.71090 0.01400 Mg1 0.17363 0.33548 0.02070 0.00700 Mg2 0.15700 0.33050 0.42910 0.02260 Mg3 0.33333 0.66667 0.51700 0.01430 Mg4 0.33333 0.66667 0.92270 0.03540 Ca1 0.52088 0.51238 0.46410 0.02140 Ca2 -0.02440 -0.01530 -0.03080 0.02200 O1 0.43790 0.24130 0.71820 0.01710 O2 0.30200 0.56350 0.71950 0.01820 O3 0.25990 0.19710 -0.28670 0.01820 O4 0.24030 0.30300 0.22990 0.01700 O5 0.34810 0.26560 0.36780 0.02060 O6 0.26640 0.41920 0.56960 0.02570 O7 0.29660 0.43750 0.89330 0.01470 O8 0.39960 0.41790 0.25500 0.01720 O9 0.42020 0.51970 0.68480 0.01810 O10 0.57050 0.35170 0.87420 0.03500 O11 0.15330 0.22100 -0.11950 0.03700 O12 0.48010 0.39870 0.71030 0.03700 O13 0.10090 0.08190 -0.28060 0.03500 O14 0.35670 0.29530 0.04270 0.02420 O15 0.14210 0.21850 -0.43840 0.03500 O16 0.57060 0.35160 0.54550 0.04100 loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_23 S1 0.01440 0.01820 0.00690 0.00900 0.00170 -0.00630 S2 0.01450 0.01220 0.01840 0.00630 -0.00270 0.00660 S3 0.01460 0.01470 0.01270 0.00950 -0.00800 -0.01000 S4 0.01280 0.01600 0.01550 0.00880 0.00930 0.00220 Mg1 0.00620 0.00910 0.00720 0.00490 -0.00310 0.00010 Mg2 0.02210 0.03370 0.01110 0.01320 0.00670 -0.00050 Mg3 0.01150 0.01150 0.02000 0.00580 0.00000 0.00000 Mg4 0.03900 0.03900 0.02800 0.01950 0.00000 0.00000 Ca1 0.00940 0.03130 0.00770 -0.00160 0.00590 0.00130 Ca2 0.02900 0.01200 0.03000 0.01400 -0.00700 -0.00700 O1 0.01100 0.03100 0.00900 0.01100 0.00100 0.00100 O2 0.02600 0.02100 0.01600 0.01900 0.00100 0.00200 O3 0.01400 0.01100 0.02300 0.00100 -0.00100 -0.00200 O4 0.01800 0.02500 0.01000 0.01200 -0.00300 -0.00300 O5 0.02500 0.02800 0.01400 0.01700 0.00900 0.01300 O6 0.01400 0.02400 0.03400 0.00500 -0.00800 -0.02400 O7 0.02600 0.01900 0.00200 0.01300 0.00000 -0.00300 O8 0.01800 0.01500 0.01300 0.00500 0.00100 -0.00300 O9 0.01300 0.01500 0.02600 0.00700 -0.00400 -0.00600 O10 0.04400 0.02800 0.02300 0.00900 0.00100 0.01300 O11 0.03400 0.07300 0.01600 0.03700 -0.01900 -0.02400 O12 0.02200 0.02100 0.06700 0.00900 0.00600 -0.00100 O13 0.01900 0.01800 0.05400 -0.00100 -0.00200 0.01000 O14 0.03300 0.02900 0.02200 0.02300 0.01200 -0.00400 O15 0.03000 0.05000 0.03100 0.02400 -0.00200 0.01800 O16 0.03800 0.03700 0.03700 0.00900 0.01800 0.00300