data_global _chemical_name_mineral 'Poldervaartite' loop_ _publ_author_name 'Dai Y S' 'Harlow G E' 'McGhie A R' _journal_name_full 'American Mineralogist' _journal_volume 78 _journal_year 1993 _journal_page_first 1082 _journal_page_last 1087 _publ_section_title ; Poldervaartite, Ca(Ca0.5Mn0.5)(SiO3OH)(OH), a new acid nesosilicate from the Kalahari manganese field, South Africa: Crystal structure and description ; _database_code_amcsd 0001615 _chemical_formula_sum 'Ca1.67 Mn.33 Si O5 H2' _cell_length_a 9.398 _cell_length_b 9.139 _cell_length_c 10.535 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 904.833 _exptl_crystal_density_diffrn 2.865 _symmetry_space_group_name_H-M 'P b c a' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,1/2+z' '-x,1/2+y,1/2-z' '1/2-x,1/2+y,z' '1/2+x,1/2-y,-z' '1/2+x,y,1/2-z' '1/2-x,-y,1/2+z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_U_iso_or_equiv Ca1 0.15406 0.49326 0.39021 1.00000 ? Ca2 0.51266 0.33390 0.43048 0.67000 ? Mn 0.51266 0.33390 0.43048 0.33000 ? Si 0.32973 0.21515 0.65939 1.00000 ? O-h1 0.25180 0.35020 0.57350 1.00000 ? O2 -0.05590 0.35900 0.43680 1.00000 ? O3 0.10200 0.71010 0.28290 1.00000 ? O-h4 0.39650 0.54920 0.39800 1.00000 ? O5 0.20190 0.39860 0.18930 1.00000 ? H1 0.25700 0.07400 0.11700 1.00000 0.03000 H2 -0.08400 0.58800 0.17300 1.00000 0.03000 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 Ca1 0.00900 0.01010 0.00840 -0.00040 0.00070 0.00030 Ca2 0.01010 0.01040 0.00980 -0.00220 -0.00030 -0.00040 Mn 0.01010 0.01040 0.00980 -0.00220 -0.00030 -0.00040 Si 0.00760 0.00750 0.00690 0.00020 -0.00020 -0.00040 O-h1 0.02800 0.01040 0.01400 0.00460 -0.00840 -0.00050 O2 0.00920 0.01450 0.01170 -0.00190 -0.00020 -0.00420 O3 0.01600 0.01340 0.00870 0.00220 0.00450 0.00430 O-h4 0.01180 0.01900 0.01600 -0.00120 -0.00020 0.00630 O5 0.01460 0.01450 0.01290 0.00440 0.00180 -0.00160