data_global _publ_contact_author_name 'Roth, Georg' _publ_contact_author_address ;Institut f\"ur Kristallographie RWTH Aachen J\"agerstr. 17-19 D-52056 Aachen Germany ; _publ_contact_author_email roth@xtal.rwth-aachen.de _publ_contact_author_fax '49(241)8096913' _publ_contact_author_phone '49(241)8092184' _publ_requested_journal 'Acta Crystallographica Section B' _publ_section_title ; Reinvestigation of the structure of BaCuSi~2~O~6~ - Evidence for a phase transition at high temperature ; #loop_ #_publ_author_name #_publ_author_address # 'Sparta, Karine' #;Institut f\"ur Kristallographie # RWTH Aachen # J\"agerstr. 17-19 # D-52056 Aachen # Germany #;'Roth, Georg' #;Institut f\"ur Kristallographie # RWTH Aachen # J\"agerstr. 17-19 # D-52056 Aachen # Germany #; #-------------# # 640 K # #-------------# data_bcso640 _audit_creation_method SHELXL-97 _chemical_name_systematic ; Barium copper cyclosilicate ; _chemical_name_common 'Barium copper cyclosilicate' _chemical_melting_point ? _chemical_formula_moiety 'Cu O6 Si2, Ba' _chemical_formula_sum 'Ba Cu O6 Si2' _chemical_formula_weight 353.06 _chemical_compound_source synthetic loop_ _atom_type_symbol _atom_type_description _atom_type_scat_dispersion_real _atom_type_scat_dispersion_imag _atom_type_scat_source 'Ba' 'Ba' -0.6130 2.2820 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'Cu' 'Cu' 0.2630 1.2660 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'Si' 'Si' 0.0720 0.0710 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'O' 'O' 0.0080 0.0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' _symmetry_cell_setting tetragonal _symmetry_space_group_name_H-M 'I 4/m m m' _symmetry_space_group_name_Hall '-I 4 2' loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-y, x, z' '-x, -y, z' 'y, -x, z' '-x, y, z' 'y, x, z' 'x, -y, z' '-y, -x, z' 'x+1/2, y+1/2, z+1/2' '-y+1/2, x+1/2, z+1/2' '-x+1/2, -y+1/2, z+1/2' 'y+1/2, -x+1/2, z+1/2' '-x+1/2, y+1/2, z+1/2' 'y+1/2, x+1/2, z+1/2' 'x+1/2, -y+1/2, z+1/2' '-y+1/2, -x+1/2, z+1/2' '-x, -y, -z' 'y, -x, -z' 'x, y, -z' '-y, x, -z' 'x, -y, -z' '-y, -x, -z' '-x, y, -z' 'y, x, -z' '-x+1/2, -y+1/2, -z+1/2' 'y+1/2, -x+1/2, -z+1/2' 'x+1/2, y+1/2, -z+1/2' '-y+1/2, x+1/2, -z+1/2' 'x+1/2, -y+1/2, -z+1/2' '-y+1/2, -x+1/2, -z+1/2' '-x+1/2, y+1/2, -z+1/2' 'y+1/2, x+1/2, -z+1/2' _cell_length_a 7.1104(13) _cell_length_b 7.1104(13) _cell_length_c 11.175(3) _cell_angle_alpha 90.00 _cell_angle_beta 90.00 _cell_angle_gamma 90.00 _cell_volume 565.0(2) _cell_formula_units_Z 4 _cell_measurement_temperature 640(2) _cell_measurement_reflns_used 988 _cell_measurement_theta_min 3.40 _cell_measurement_theta_max 24.81 _exptl_crystal_description cuboid _exptl_crystal_colour purple _exptl_crystal_size_max 0.27 _exptl_crystal_size_mid 0.24 _exptl_crystal_size_min 0.17 _exptl_crystal_density_meas ? _exptl_crystal_density_diffrn 4.151 _exptl_crystal_density_method 'not measured' _exptl_crystal_F_000 644 _exptl_absorpt_coefficient_mu 11.08 _exptl_absorpt_correction_type numerical _exptl_absorpt_correction_T_min 0.0501 _exptl_absorpt_correction_T_max 0.1438 _exptl_absorpt_process_details 'via equivalents using STOE X-SHAPE and X-RED (Stoe & Cie, 1996)' _diffrn_ambient_temperature 640(2) _diffrn_radiation_wavelength 0.71069 _diffrn_radiation_type MoK\a _diffrn_radiation_source 'fine-focus sealed tube' _diffrn_radiation_monochromator graphite _diffrn_measurement_device_type 'STOE IPDS' _diffrn_measurement_method 'rotation method' _diffrn_detector_area_resol_mean ? _diffrn_standards_number 0 _diffrn_standards_interval_count 0 _diffrn_standards_interval_time 0 _diffrn_standards_decay_% 0 _diffrn_reflns_number 170 _diffrn_reflns_av_R_equivalents 0.0000 _diffrn_reflns_av_sigmaI/netI 0.0371 _diffrn_reflns_limit_h_min 0 _diffrn_reflns_limit_h_max 8 _diffrn_reflns_limit_k_min 0 _diffrn_reflns_limit_k_max 8 _diffrn_reflns_limit_l_min 0 _diffrn_reflns_limit_l_max 13 _diffrn_reflns_theta_min 3.40 _diffrn_reflns_theta_max 24.81 _reflns_number_total 170 _reflns_number_gt 135 _reflns_threshold_expression >2sigma(I) _computing_data_collection ? _computing_cell_refinement ? _computing_data_reduction 'STOE X-RED' _computing_structure_solution ? _computing_structure_refinement 'SHELXL-97 (Sheldrick, 1997)' _computing_molecular_graphics 'ATOMS v5.1' _computing_publication_material 'WinGX v1.64.05 (Farrugia, 1999)' _refine_special_details ; Refinement of F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > 2sigma(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. ; _refine_ls_structure_factor_coef Fsqd _refine_ls_matrix_type full _refine_ls_weighting_scheme calc _refine_ls_weighting_details 'calc w=1/[\s^2^(Fo^2^)+(0.0000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3' _atom_sites_solution_primary direct _atom_sites_solution_secondary difmap _atom_sites_solution_hydrogens geom _refine_ls_hydrogen_treatment mixed _refine_ls_extinction_method SHELXL _refine_ls_extinction_coef 0.0021(2) _refine_ls_extinction_expression 'Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^' _refine_ls_number_reflns 170 _refine_ls_number_parameters 23 _refine_ls_number_restraints 0 _refine_ls_R_factor_all 0.0217 _refine_ls_R_factor_gt 0.0153 _refine_ls_wR_factor_ref 0.0251 _refine_ls_wR_factor_gt 0.0249 _refine_ls_goodness_of_fit_ref 1.023 _refine_ls_restrained_S_all 1.023 _refine_ls_shift/su_max 0.000 _refine_ls_shift/su_mean 0.000 _refine_diff_density_max 0.525 _refine_diff_density_min -0.508 _refine_diff_density_rms 0.109 loop_ _atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv _atom_site_adp_type _atom_site_occupancy _atom_site_symmetry_multiplicity _atom_site_calc_flag _atom_site_refinement_flags _atom_site_disorder_assembly _atom_site_disorder_group Ba Ba 0.0000 0.5000 0.2500 0.0242(3) Uani 1 8 d S . . Cu Cu 0.0000 0.0000 0.12341(16) 0.0200(5) Uani 1 8 d S . . Si Si 0.2756(2) 0.2756(2) 0.0000 0.0157(7) Uani 1 4 d S . . O1 O 0.2415(14) 0.5000 0.0239(18) 0.034(6) Uani 0.50 2 d SP . . O2 O 0.1916(5) 0.1916(5) 0.1209(4) 0.0392(14) Uani 1 2 d S . . loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_23 _atom_site_aniso_U_13 _atom_site_aniso_U_12 Ba 0.0238(4) 0.0238(4) 0.0250(5) 0.000 0.000 0.000 Cu 0.0190(7) 0.0190(7) 0.0220(11) 0.000 0.000 0.000 Si 0.0101(9) 0.0101(9) 0.0269(14) 0.000 0.000 -0.0010(14) O1 0.049(5) 0.010(3) 0.043(19) 0.000 0.022(8) 0.000 O2 0.0478(19) 0.0478(19) 0.022(2) 0.0004(17) 0.0004(17) -0.021(2) _geom_special_details ; All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. ; loop_ _geom_bond_atom_site_label_1 _geom_bond_atom_site_label_2 _geom_bond_distance _geom_bond_site_symmetry_2 _geom_bond_publ_flag Ba O2 2.958(2) 28 ? Ba O2 2.958(2) 2 ? Ba O2 2.958(2) . ? Ba O2 2.958(2) 25 ? Ba O2 2.958(2) 4_565 ? Ba O2 2.958(2) 26_455 ? Ba O2 2.958(2) 27_455 ? Ba O2 2.958(2) 3_565 ? Ba O1 3.056(18) 3_565 ? Ba O1 3.056(18) 28 ? Ba O1 3.056(18) 26_455 ? Ba O1 3.056(18) . ? Cu O2 1.927(5) 3 ? Cu O2 1.927(5) . ? Cu O2 1.927(5) 4 ? Cu O2 1.927(5) 2 ? Si O2 1.593(5) 19 ? Si O2 1.593(5) . ? Si O1 1.636(4) . ? Si O1 1.636(4) 2_655 ? Si O1 1.636(4) 19 ? Si O1 1.636(4) 20_655 ? O1 O1 0.53(4) 19 ? O1 Si 1.636(4) 18_565 ? O1 O2 2.472(10) 4_565 ? O1 O2 2.472(10) . ? O1 O1 2.599(14) 4_565 ? O1 O1 2.599(14) 2_655 ? O1 O1 2.653(17) 18_565 ? O1 O1 2.653(17) 20_655 ? O1 O2 2.748(13) 19 ? O1 O2 2.748(13) 18_565 ? O2 O1 2.472(10) 2_655 ? O2 O2 2.701(9) 19 ? O2 O2 2.725(7) 4 ? O2 O2 2.725(7) 2 ? O2 O1 2.748(13) 19 ? O2 O1 2.748(13) 20_655 ? O2 Ba 2.958(2) 25 ? O2 O2 3.116(9) 25 ? loop_ _geom_angle_atom_site_label_1 _geom_angle_atom_site_label_2 _geom_angle_atom_site_label_3 _geom_angle _geom_angle_site_symmetry_1 _geom_angle_site_symmetry_3 _geom_angle_publ_flag O2 Ba O2 157.09(18) 28 2 ? O2 Ba O2 103.77(7) 28 . ? O2 Ba O2 54.85(17) 2 . ? O2 Ba O2 54.85(17) 28 25 ? O2 Ba O2 103.77(7) 2 25 ? O2 Ba O2 63.58(15) . 25 ? O2 Ba O2 63.58(15) 28 4_565 ? O2 Ba O2 121.59(16) 2 4_565 ? O2 Ba O2 95.71(18) . 4_565 ? O2 Ba O2 103.77(7) 25 4_565 ? O2 Ba O2 121.59(16) 28 26_455 ? O2 Ba O2 63.58(15) 2 26_455 ? O2 Ba O2 103.77(7) . 26_455 ? O2 Ba O2 95.71(18) 25 26_455 ? O2 Ba O2 157.09(18) 4_565 26_455 ? O2 Ba O2 95.71(18) 28 27_455 ? O2 Ba O2 103.77(7) 2 27_455 ? O2 Ba O2 157.09(18) . 27_455 ? O2 Ba O2 121.59(16) 25 27_455 ? O2 Ba O2 103.77(7) 4_565 27_455 ? O2 Ba O2 54.85(17) 26_455 27_455 ? O2 Ba O2 103.77(7) 28 3_565 ? O2 Ba O2 95.71(18) 2 3_565 ? O2 Ba O2 121.59(16) . 3_565 ? O2 Ba O2 157.09(18) 25 3_565 ? O2 Ba O2 54.85(17) 4_565 3_565 ? O2 Ba O2 103.77(7) 26_455 3_565 ? O2 Ba O2 63.58(15) 27_455 3_565 ? O2 Ba O1 145.12(17) 28 3_565 ? O2 Ba O1 48.51(10) 2 3_565 ? O2 Ba O1 81.68(18) . 3_565 ? O2 Ba O1 145.12(17) 25 3_565 ? O2 Ba O1 81.68(18) 4_565 3_565 ? O2 Ba O1 89.2(2) 26_455 3_565 ? O2 Ba O1 89.2(2) 27_455 3_565 ? O2 Ba O1 48.51(10) 3_565 3_565 ? O2 Ba O1 48.51(10) 28 28 ? O2 Ba O1 145.12(17) 2 28 ? O2 Ba O1 145.12(17) . 28 ? O2 Ba O1 81.68(18) 25 28 ? O2 Ba O1 89.2(2) 4_565 28 ? O2 Ba O1 81.68(18) 26_455 28 ? O2 Ba O1 48.51(10) 27_455 28 ? O2 Ba O1 89.2(2) 3_565 28 ? O1 Ba O1 133.2(3) 3_565 28 ? O2 Ba O1 81.68(18) 28 26_455 ? O2 Ba O1 89.2(2) 2 26_455 ? O2 Ba O1 89.2(2) . 26_455 ? O2 Ba O1 48.51(10) 25 26_455 ? O2 Ba O1 145.12(17) 4_565 26_455 ? O2 Ba O1 48.51(10) 26_455 26_455 ? O2 Ba O1 81.68(18) 27_455 26_455 ? O2 Ba O1 145.12(17) 3_565 26_455 ? O1 Ba O1 133.2(3) 3_565 26_455 ? O1 Ba O1 68.4(5) 28 26_455 ? O2 Ba O1 89.2(2) 28 . ? O2 Ba O1 81.68(18) 2 . ? O2 Ba O1 48.51(10) . . ? O2 Ba O1 89.2(2) 25 . ? O2 Ba O1 48.51(10) 4_565 . ? O2 Ba O1 145.12(17) 26_455 . ? O2 Ba O1 145.12(17) 27_455 . ? O2 Ba O1 81.68(18) 3_565 . ? O1 Ba O1 68.4(5) 3_565 . ? O1 Ba O1 133.2(3) 28 . ? O1 Ba O1 133.2(3) 26_455 . ? O2 Cu O2 178.3(3) 3 . ? O2 Cu O2 89.988(5) 3 4 ? O2 Cu O2 89.988(5) . 4 ? O2 Cu O2 89.988(5) 3 2 ? O2 Cu O2 89.988(5) . 2 ? O2 Cu O2 178.3(3) 4 2 ? O2 Si O2 116.0(3) 19 . ? O2 Si O1 116.6(6) 19 . ? O2 Si O1 99.9(7) . . ? O2 Si O1 116.6(6) 19 2_655 ? O2 Si O1 99.9(7) . 2_655 ? O1 Si O1 105.2(7) . 2_655 ? O2 Si O1 99.9(7) 19 19 ? O2 Si O1 116.6(6) . 19 ? O1 Si O1 18.8(14) . 19 ? O1 Si O1 108.4(7) 2_655 19 ? O2 Si O1 99.9(7) 19 20_655 ? O2 Si O1 116.6(6) . 20_655 ? O1 Si O1 108.4(7) . 20_655 ? O1 Si O1 18.8(14) 2_655 20_655 ? O1 Si O1 105.2(7) 19 20_655 ? Si O1 Si 154.6(12) 18_565 . ? Si O1 Ba 102.6(6) 18_565 . ? Si O1 Ba 102.6(6) . . ? Si O2 Cu 122.9(3) . . ? Si O2 Ba 107.96(13) . . ? Cu O2 Ba 101.03(13) . . ? Si O2 Ba 107.96(13) . 25 ? Cu O2 Ba 101.03(13) . 25 ? Ba O2 Ba 116.42(15) . 25 ? _diffrn_measured_fraction_theta_max 1.000 _diffrn_reflns_theta_full 24.81 _diffrn_measured_fraction_theta_full 1.000