data_global _chemical_name_mineral 'Gypsum' loop_ _publ_author_name 'Knight K S' 'Stretton I C' 'Schofield P F' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 26 _journal_year 1999 _journal_page_first 477 _journal_page_last 483 _publ_section_title ; Temperature evolution between 50 K and 320 K of the thermal expansion tensor of gypsum derived from neutron powder diffraction data Sample: T = 320 K ; _database_code_amcsd 0008228 _chemical_formula_sum 'Ca S O6 D4' _cell_length_a 5.6769 _cell_length_b 15.2074 _cell_length_c 6.5277 _cell_angle_alpha 90 _cell_angle_beta 118.494 _cell_angle_gamma 90 _cell_volume 495.279 _exptl_crystal_density_diffrn 2.363 _symmetry_space_group_name_H-M 'I 1 2/a 1' loop_ _space_group_symop_operation_xyz 'x,y,z' '1/2+x,1/2+y,1/2+z' '-x,y,1/2-z' '1/2-x,1/2+y,-z' '1/2+x,1/2-y,z' '+x,-y,1/2+z' '1/2-x,1/2-y,1/2-z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z Ca 0.50000 0.07860 0.25000 S 0.00000 0.07870 0.75000 O1 -0.03840 0.13260 0.55120 O2 0.24290 0.02150 0.83470 Ow 0.37840 0.18250 0.45540 D1 0.25040 0.16150 0.50090 D2 0.40220 0.24350 0.49000