data_global _chemical_name_mineral 'Oxy-dravite' loop_ _publ_author_name 'Gatta G D' 'Bosi F' 'McIntyre G J' 'Skogby H' _journal_name_full 'Mineralogical Magazine' _journal_volume 78 _journal_year 2014 _journal_page_first 681 _journal_page_last 692 _publ_section_title ; First accurate location of two proton sites in tourmaline: A single-crystal neutron diffraction study of oxy-dravite Note: H1 site on the three-fold axis ; _database_code_amcsd 0020483 _chemical_compound_source 'Osarara, Narok District, Kenya' _chemical_formula_sum 'Na.866 Al6.624 Mg1.776 Fe.6 B3 Si6 O31 H3.194' _cell_length_a 15.9272 _cell_length_b 15.9272 _cell_length_c 7.2001 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 1581.787 _exptl_crystal_density_diffrn 3.072 _symmetry_space_group_name_H-M 'R 3 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '2/3+x,1/3+y,1/3+z' '1/3+x,2/3+y,2/3+z' 'x,x-y,z' '2/3+x,1/3+x-y,1/3+z' '1/3+x,2/3+x-y,2/3+z' '-y,-x,z' '2/3-y,1/3-x,1/3+z' '1/3-y,2/3-x,2/3+z' '-x+y,y,z' '2/3-x+y,1/3+y,1/3+z' '1/3-x+y,2/3+y,2/3+z' '-y,x-y,z' '2/3-y,1/3+x-y,1/3+z' '1/3-y,2/3+x-y,2/3+z' '-x+y,-x,z' '2/3-x+y,1/3-x,1/3+z' '1/3-x+y,2/3-x,2/3+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 NaX 0.00000 0.00000 0.23230 0.86600 0.01050 AlY 0.12264 0.06132 0.63587 0.52600 0.00528 MgY 0.12264 0.06132 0.63587 0.27400 0.00528 FeY 0.12264 0.06132 0.63587 0.20000 0.00528 AlZ 0.29767 0.26140 0.61072 0.84100 0.00251 MgZ 0.29767 0.26140 0.61072 0.15900 0.00251 B 0.10991 0.21982 0.45430 1.00000 0.00353 SiT 0.19161 0.18988 0.00084 1.00000 0.00300 O1 0.00000 0.00000 0.77115 1.00000 0.00943 O2 0.06069 0.12138 0.48767 1.00000 0.00766 O3 0.26138 0.13069 0.50988 1.00800 0.01060 O4 0.09379 0.18759 0.07268 1.00000 0.00618 O5 0.18437 0.09219 0.09380 1.00000 0.00603 O6 0.19456 0.18438 0.77774 1.00000 0.00579 O7 0.28540 0.28484 0.07821 1.00000 0.00586 O8 0.20920 0.27008 0.43993 1.00000 0.00688 H3 0.25760 0.12880 0.37511 0.98300 0.02630 H1 0.00000 0.00000 0.90420 0.24500 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 NaX 0.00820 0.00820 0.01500 0.00410 0.00000 0.00000 AlY 0.00540 0.00330 0.00780 0.00270 0.00280 0.00140 MgY 0.00540 0.00330 0.00780 0.00270 0.00280 0.00140 FeY 0.00540 0.00330 0.00780 0.00270 0.00280 0.00140 AlZ 0.00230 0.00200 0.00300 0.00080 0.00040 0.00010 MgZ 0.00230 0.00200 0.00300 0.00080 0.00040 0.00010 B 0.00230 0.00220 0.00600 0.00110 0.00040 0.00070 SiT 0.00280 0.00230 0.00390 0.00130 0.00050 0.00040 O1 0.01110 0.01110 0.00600 0.00560 0.00000 0.00000 O2 0.00960 0.00320 0.00800 0.00160 0.00040 0.00090 O3 0.01880 0.01040 0.00540 0.00940 0.00070 0.00040 O4 0.00420 0.00880 0.00710 0.00440 0.00070 0.00140 O5 0.00820 0.00420 0.00700 0.00410 0.00070 0.00030 O6 0.00730 0.00750 0.00450 0.00520 0.00070 0.00080 O7 0.00490 0.00360 0.00700 0.00060 0.00240 0.00050 O8 0.00340 0.00610 0.01120 0.00250 0.00060 0.00110 H3 0.04690 0.02990 0.00810 0.02320 0.00090 0.00050