Phase transitions in K~2~Cr~2~O~7~ and structural redeterminations of phase II
Weakley, T. J. R.; Ylvisaker, E. R.; Yager, R. J.; Stephens, J. E.; Wiegel, R. D.; Mengis, M.; Bauer, M. R.; Wu, P.; Photinos, P.; Abrahams, S. C.; Acta Crystallographica, Section B: Structural Science 60 (2004) 705–715; doi:10.1107/s010876810402333x

data_9011306
_publ_section_title
;
 Phase transitions in K~2~Cr~2~O~7~ and structural redeterminations of phase II
;
_journal_coden_ASTM              ASBSDK
_journal_issue                   6
_journal_name_full
;
 Acta Crystallographica, Section B: Structural Science
;
_journal_page_first              705
_journal_page_last               715
_journal_paper_doi               10.1107/s010876810402333x
_journal_volume                  60
_journal_year                    2004
_chemical_formula_moiety         'K2 Cr2 O7 '
_chemical_formula_sum            'Cr2 K2 O7'
_chemical_formula_weight         294.18
_chemical_melting_point          659
_chemical_name_mineral           Lopezite
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_cell_angle_alpha                96.205
_cell_angle_beta                 98.033
_cell_angle_gamma                90.914
_cell_formula_units_Z            4
_cell_length_a                   7.3807
_cell_length_b                   7.4593
_cell_length_c                   13.3910
_cell_measurement_reflns_used    25
_cell_measurement_temperature    296
_cell_measurement_theta_max      15.0
_cell_measurement_theta_min      14.0
_cell_volume                     725.368
_computing_cell_refinement       'CAD4/PC (Enraf-Nonius, 1993)'
_computing_data_collection       'CAD4/PC (Enraf-Nonius, 1993)'
_computing_data_reduction        'TEXSAN (Molecular Structure Corp., 1997)'
_computing_publication_material  'TEXSAN (Molecular Structure Corp., 1997)'
_computing_structure_refinement  'TEXSAN (Molecular Structure Corp., 1997)'
_computing_structure_solution    'TEXSAN (Molecular Structure Corp., 1997)'
_diffrn_ambient_temperature      296
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device_type  'Nonius CAD-4 serial diffractometer'
_diffrn_measurement_method       \w-2\q
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'sealed X-ray tube'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0114
_diffrn_reflns_av_sigmaI/netI    0.030
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            4533
_diffrn_reflns_reduction_process 'Lp corrections applied'
_diffrn_reflns_theta_full        30.0
_diffrn_reflns_theta_max         30.0
_diffrn_reflns_theta_min         1.5
_diffrn_standards_decay_%        0.00
_diffrn_standards_interval_count 300
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    4.132
_exptl_absorpt_correction_T_max  0.560
_exptl_absorpt_correction_T_min  0.382
_exptl_absorpt_correction_type   refdelf
_exptl_absorpt_process_details   'DIFABS (Walker & Stuart, 1983)'
_exptl_crystal_colour            intense-orange
_exptl_crystal_density_diffrn    2.694
_exptl_crystal_density_meas      2.676
_exptl_crystal_description       block
_exptl_crystal_F_000             568
_exptl_crystal_size_max          0.27
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.49
_refine_diff_density_min         -0.40
_refine_ls_abs_structure_details 'not applicable'
_refine_ls_extinction_coef       '1.27 x 10^-6^'
_refine_ls_extinction_expression 'equ(3) Acta Cryst.(1968) A24, p213.'
_refine_ls_extinction_method     'Zachariasen (1967)'
_refine_ls_goodness_of_fit_all   1.58
_refine_ls_goodness_of_fit_ref   1.74
_refine_ls_matrix_type           full
_refine_ls_number_constraints    0
_refine_ls_number_parameters     200
_refine_ls_number_reflns         4227
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.036
_refine_ls_R_factor_gt           0.025
_refine_ls_shift/su_max          0.020
_refine_ls_shift/su_mean         0.0014
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details     'w = 4F~o~^2^/[\s^2^(I) + (0.025I)^2^]'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.074
_refine_ls_wR_factor_ref         0.040
_reflns_number_gt                4096
_reflns_number_total             4227
_reflns_threshold_expression     I>1.00\s(I)
_cod_duplicate_entry             2102644
_cod_data_source_file            bk0147.cif
_cod_data_source_block           1
_cod_original_cell_volume        725.37(16)
_cod_original_formula_sum        'Cr2 K2 O7 '
_cod_database_code               9011306