Redetermination of kovdorskite, Mg~2~PO~4~(OH)·3H~2~O
Morrison, Shaunna M.; Downs, Robert T.; Yang, Hexiong; Acta Crystallographica Section E 68 (2012) i12–i13; doi:10.1107/S1600536812000256

data_2233662
_publ_section_title
;
 Redetermination of kovdorskite, Mg~2~PO~4~(OH)&#x00B7;3H~2~O
;
_journal_coeditor_code           WM2577
_journal_issue                   2
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i12
_journal_page_last               i13
_journal_paper_doi               10.1107/S1600536812000256
_journal_volume                  68
_journal_year                    2012
_chemical_formula_iupac          'Mg2 P O4 (O H), 3H2 O'
_chemical_formula_sum            'H7 Mg2 O8 P'
_chemical_formula_weight         214.65
_chemical_name_common            Kovdorskite
_chemical_name_systematic
;
dimagnesium phosphate hydroxide trihydrate
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yab'
_symmetry_space_group_name_H-M   'P 1 21/a 1'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 105.0540(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   10.47850(10)
_cell_length_b                   12.9336(2)
_cell_length_c                   4.73080(10)
_cell_measurement_reflns_used    4644
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      32.499
_cell_measurement_theta_min      2.655
_cell_volume                     619.137(18)
_computing_cell_refinement       'SAINT (Bruker, 2004)'
_computing_data_collection       'APEX2 (Bruker, 2004)'
_computing_data_reduction        'SAINT (Bruker, 2004)'
_computing_molecular_graphics    'XtalDraw (Downs & Hall-Wallace, 2003)'
_computing_publication_material  'publCIF (Westrip, 2010)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Bruker APEXII CCD area-detector'
_diffrn_measurement_method       '\f and \w scan'
_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  0.0263
_diffrn_reflns_av_sigmaI/netI    0.0224
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            8463
_diffrn_reflns_theta_full        32.52
_diffrn_reflns_theta_max         32.52
_diffrn_reflns_theta_min         3.15
_exptl_absorpt_coefficient_mu    0.649
_exptl_absorpt_correction_T_max  0.9439
_exptl_absorpt_correction_T_min  0.9380
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(<i>SADABS</i>; Sheldrick, 2005)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    2.303
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       cuboid
_exptl_crystal_F_000             440
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.09
_exptl_crystal_size_min          0.09
_refine_diff_density_max         0.498
_refine_diff_density_min         -0.341
_refine_ls_extinction_coef       0.014(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL97 (Sheldrick, 2008)'
_refine_ls_goodness_of_fit_ref   1.073
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     129
_refine_ls_number_reflns         2231
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.073
_refine_ls_R_factor_all          0.0266
_refine_ls_R_factor_gt           0.0222
_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^)+(0.0278P)^2^+0.1500P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0544
_refine_ls_wR_factor_ref         0.0564
_reflns_number_gt                2008
_reflns_number_total             2231
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            wm2577.cif
_cod_data_source_block           I
_cod_original_cell_volume        619.137(17)
_cod_original_sg_symbol_H-M      'P 21/a'
_cod_database_code               2233662
_cod_database_fobs_code          2233662