A new polymorph of magnesium oxalate dihydrate
Chen, Xue-An; Song, Fang-Ping; Chang, Xin-An; Zang, He-Gui; Xiao, Wei-Qiang; Acta Crystallographica Section E 64 (2008) m863–; doi:10.1107/S1600536808015870

data_2218789
_publ_section_title
;
 A new polymorph of magnesium oxalate dihydrate
;
_journal_coeditor_code           PV2083
_journal_issue                   7
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              m863
_journal_paper_doi               10.1107/S1600536808015870
_journal_volume                  64
_journal_year                    2008
_chemical_formula_iupac          '[Mg (C2 O4) (H2 O)2]'
_chemical_formula_moiety         'C2 H4 Mg O6'
_chemical_formula_sum            'C2 H4 Mg O6'
_chemical_formula_weight         148.36
_chemical_name_systematic
;
catena-poly[[diaquamagnesium(II)]-\m-oxalato]
;
_space_group_IT_number           70
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-F 2uv 2vw'
_symmetry_space_group_name_H-M   'F d d d :2'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   5.3940(11)
_cell_length_b                   12.691(3)
_cell_length_c                   15.399(3)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    290
_cell_measurement_theta_max      19.64
_cell_measurement_theta_min      12.95
_cell_volume                     1054.1(4)
_computing_cell_refinement
'Rigaku/AFC Diffractometer Control Software (Rigaku, 1994)'
_computing_data_collection
'Rigaku/AFC Diffractometer Control Software (Rigaku, 1994)'
_computing_data_reduction
'Rigaku/AFC Diffractometer Control Software (Rigaku, 1994)'
_computing_molecular_graphics    'ATOMS (Dowty, 1999)'
_computing_publication_material  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      290
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Rigaku AFC-7R'
_diffrn_measurement_method       2\q/\w
_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  0.0540
_diffrn_reflns_av_sigmaI/netI    0.0366
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1110
_diffrn_reflns_theta_full        32.48
_diffrn_reflns_theta_max         32.48
_diffrn_reflns_theta_min         4.16
_diffrn_standards_decay_%        1.10
_diffrn_standards_interval_count 150
_diffrn_standards_interval_time  120
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.293
_exptl_absorpt_correction_T_max  0.962
_exptl_absorpt_correction_T_min  0.915
_exptl_absorpt_correction_type   psi-scan
_exptl_absorpt_process_details   '(Kopfmann & Huber, 1968)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.870
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             608
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.892
_refine_diff_density_min         -0.479
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.966
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     27
_refine_ls_number_reflns         483
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.966
_refine_ls_R_factor_all          0.0616
_refine_ls_R_factor_gt           0.0342
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w = 1/[\s^2^(Fo^2^)+(0.0683P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1048
_refine_ls_wR_factor_ref         0.1096
_reflns_number_gt                321
_reflns_number_total             483
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            pv2083.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'F d d d'
_cod_database_code               2218789
_cod_database_fobs_code          2218789