Cooperative Jahn‒Teller effect and the role of strain in the tetragonal-to-cubic phase transition in Mg<i>~x~</i>Cu~1{ηskip0.16667em~{-}{ηskip0.16667em}<i>x</i>}Cr~2~O~4~
Tarantino, Serena C.; Giannini, Mattia; Carpenter, Michael A.; Zema, Michele; IUCrJ 3 (2016) –; doi:10.1107/S2052252516012574

data_1543900
_publ_section_title
;
 Cooperative Jahn--Teller effect and the role of strain in the
 tetragonal-to-cubic phase transition in
 Mg<i>~x~</i>Cu~1{\hskip0.16667em~{-}{\hskip0.16667em}<i>x</i>}Cr~2~O~4~
;
_journal_issue                   5
_journal_name_full               IUCrJ
_journal_page_first
;
;
_journal_paper_doi               10.1107/S2052252516012574
_journal_volume                  3
_journal_year                    2016
_chemical_formula_sum            'Cr2 Mg O4'
_chemical_formula_weight         192.31
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           227
_symmetry_cell_setting           cubic
_symmetry_space_group_name_Hall  '-F 4vw 2vw 3'
_symmetry_space_group_name_H-M   'F d -3 m :2'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   8.32880(10)
_cell_length_b                   8.32880(10)
_cell_length_c                   8.32880(10)
_cell_measurement_temperature    293(2)
_cell_volume                     577.760(12)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.977
_diffrn_measured_fraction_theta_max 0.977
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0178
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            4570
_diffrn_reflns_theta_full        42.53
_diffrn_reflns_theta_max         42.53
_diffrn_reflns_theta_min         4.24
_exptl_absorpt_coefficient_mu    7.553
_exptl_crystal_density_diffrn    4.422
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             736
_refine_diff_density_max         0.629
_refine_diff_density_min         -0.542
_refine_diff_density_rms         0.119
_refine_ls_extinction_coef       0.00248(11)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.169
_refine_ls_matrix_type           full
_refine_ls_number_parameters     8
_refine_ls_number_reflns         4570
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.169
_refine_ls_R_factor_all          0.0176
_refine_ls_R_factor_gt           0.0171
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0207P)^2^+1.5590P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0469
_refine_ls_wR_factor_ref         0.0470
_reflns_number_gt                4480
_reflns_number_total             4570
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            lc5068.cif
_cod_data_source_block           Mg100_RT_CCD_C
_cod_original_sg_symbol_H-M      'F d -3 m'
_cod_database_code               1543900