data_global _chemical_name_mineral 'Topaz' loop_ _publ_author_name 'Diego Gatta G' 'Nestola F' 'Bromiley G D' 'Loose A' _journal_name_full 'American Mineralogist' _journal_volume 91 _journal_year 2006 _journal_page_first 1839 _journal_page_last 1846 _publ_section_title ; New insight into crystal chemistry of topaz: a multi-methodological study Sample: Neutron refinement at T = 10 K ; _database_code_amcsd 0004245 _chemical_compound_source 'Ouro Preto, Minas Gerias, Brazil' _chemical_formula_sum 'Al2 Si O4.42 F1.58 H.42' _cell_length_a 4.657 _cell_length_b 8.838 _cell_length_c 8.426 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 346.802 _exptl_crystal_density_diffrn 3.509 _symmetry_space_group_name_H-M 'P b n m' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,y,1/2-z' '-x,-y,1/2+z' '1/2+x,1/2-y,1/2+z' '1/2-x,1/2+y,1/2-z' '1/2-x,1/2+y,z' '1/2+x,1/2-y,-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 Al 0.90560 0.13130 0.08170 1.00000 0.00290 Si 0.39960 0.94090 0.25000 1.00000 0.00270 O1 0.70690 0.03120 0.25000 1.00000 0.00380 O2 0.45280 0.75620 0.25000 1.00000 0.00390 O3 0.21170 0.98990 0.09260 1.00000 0.00370 F4 0.59730 0.25250 0.05992 0.79000 0.00470 O4 0.59730 0.25250 0.05992 0.21000 0.00470 H4 0.49200 0.25100 0.16370 0.21000 0.02500 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 Al 0.00280 0.00130 0.00472 0.00030 -0.00050 0.00060 Si 0.00180 0.00110 0.00520 0.00030 0.00000 0.00000 O1 0.00390 0.00260 0.00500 -0.00040 0.00000 0.00000 O2 0.00420 0.00140 0.00620 0.00120 0.00000 0.00000 O3 0.00310 0.00200 0.00610 0.00060 -0.00060 0.00010 F4 0.00400 0.00280 0.00720 0.00080 -0.00030 -0.00010 O4 0.00400 0.00280 0.00720 0.00080 -0.00030 -0.00010 H4 0.02700 0.02700 0.02200 0.01000 0.01500 0.00800