data_global _chemical_name_mineral 'Chrysoberyl' loop_ _publ_author_name 'Weber S U' 'Grodzicki M' 'Lottermoser W' 'Redhammer G J' 'Tippelt G' 'Ponahlo J' 'Amthauer G' _journal_name_full 'Physics and Chemistry of Minerals' _journal_volume 34 _journal_year 2007 _journal_page_first 507 _journal_page_last 515 _publ_section_title ; 57Fe Mossbauer spectroscopy, X-ray single-crystal diffractometry, and electronic structure calculations on natural alexandrite Note: changed O1(z) from .788822 to .78822 ; _database_code_amcsd 0009096 _chemical_compound_source 'Malyshevo near Terem Tschanka, Sverdlovsk, Ural, Russia' _chemical_formula_sum 'Al1.98 Cr.02 Be O4' _cell_length_a 9.4082 _cell_length_b 5.4790 _cell_length_c 4.4288 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 90 _cell_volume 228.294 _exptl_crystal_density_diffrn 3.709 _symmetry_space_group_name_H-M 'P n m a' loop_ _space_group_symop_operation_xyz 'x,y,z' 'x,1/2-y,z' '-x,1/2+y,-z' '1/2-x,1/2+y,1/2+z' '1/2+x,1/2-y,1/2-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 Al1 0.00000 0.00000 0.00000 1.00000 0.00349 Al2 0.27282 0.25000 -0.00503 0.98000 0.00355 Cr2 0.27282 0.25000 -0.00503 0.02000 0.00355 Be 0.09289 0.25000 0.43360 1.00000 0.00530 O1 0.09022 0.25000 0.78822 1.00000 0.00332 O2 0.43316 0.25000 0.24167 1.00000 0.00370 O3 0.16324 0.01554 0.25728 1.00000 0.00401 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 Al1 0.00388 0.00286 0.00346 -0.00037 0.00006 0.00000 Al2 0.00335 0.00364 0.00366 0.00000 -0.00008 0.00000 Cr2 0.00335 0.00364 0.00366 0.00000 -0.00008 0.00000 Be 0.00630 0.00540 0.00420 0.00000 0.00000 0.00000 O1 0.00397 0.00339 0.00260 0.00000 -0.00010 0.00000 O2 0.00366 0.00387 0.00365 0.00000 -0.00041 0.00000 O3 0.00425 0.00392 0.00387 0.00030 -0.00029 0.00031