The α ↔ β phase transitions of Zn2P2O7 revisited: existence of an additional intermediate phase with an incommensurately modulated structure.
Stöger, Berthold; Weil, Matthias; Dušek, Michal; Acta Crystallographica, Section B: Structural Science, Crystal Engineering and Materials 70 (2014) 539–554; doi:10.1107/S205252061401049X

data_2310787
_publ_section_title
;
 The \a &#x2194; \b phase transitions of Zn2P2O7 revisited: existence of
 an additional intermediate phase with an incommensurately modulated
 structure.
;
_journal_coden_ASTM              ACSBDA
_journal_issue                   3
_journal_name_full
;
 Acta Crystallographica, Section B: Structural Science, Crystal Engineering
 and Materials
;
_journal_page_first              539
_journal_page_last               554
_journal_paper_doi               10.1107/S205252061401049X
_journal_volume                  70
_journal_year                    2014
_chemical_formula_sum            'O7 P2 Zn2'
_chemical_formula_weight         304.7
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-I 2yc'
_symmetry_space_group_name_H-M   'I 1 2/c 1'
_audit_update_record
;
2012-06-04 # Formatted by publCIF
;
_cell_angle_alpha                90
_cell_angle_beta                 106.338(16)
_cell_angle_gamma                90
_cell_formula_units_Z            12
_cell_length_a                   20.1131(13)
_cell_length_b                   8.2769(6)
_cell_length_c                   9.109(3)
_cell_measurement_reflns_used    9829
_cell_measurement_temperature    350
_cell_measurement_theta_max      35.0
_cell_measurement_theta_min      3.4
_cell_volume                     1455.2(5)
_diffrn_ambient_temperature      350
_diffrn_measured_fraction_theta_full 1
_diffrn_measured_fraction_theta_max 1
_diffrn_measurement_device       'four-cycle diffractometer'
_diffrn_measurement_device_type  'Bruker KAPPA APEX II CCD'
_diffrn_measurement_method       '\w and \f scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_source         'X-ray tube'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0367
_diffrn_reflns_av_sigmaI/netI    0.0122
_diffrn_reflns_av_unetI/netI     0.0122
_diffrn_reflns_limit_h_max       32
_diffrn_reflns_limit_h_min       -32
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            46498
_diffrn_reflns_theta_full        35.03
_diffrn_reflns_theta_max         35.03
_diffrn_reflns_theta_min         2.11
_exptl_absorpt_coefficient_mu    10.528
_exptl_absorpt_correction_T_max  0.73
_exptl_absorpt_correction_T_min  0.022
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            'clear colourless'
_exptl_crystal_density_diffrn    4.1709
_exptl_crystal_description       'triangular fragment'
_exptl_crystal_F_000             1752
_exptl_crystal_size_max          0.45
_exptl_crystal_size_mid          0.33
_exptl_crystal_size_min          0.03
_refine_diff_density_max         0.82
_refine_diff_density_min         -0.87
_refine_ls_extinction_coef       4210(70)
_refine_ls_extinction_method
'B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)'
_refine_ls_goodness_of_fit_gt    1.53
_refine_ls_goodness_of_fit_ref   1.47
_refine_ls_number_constraints    0
_refine_ls_number_parameters     151
_refine_ls_number_reflns         3215
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0198
_refine_ls_R_factor_gt           0.0159
_refine_ls_shift/su_max          0.0024
_refine_ls_shift/su_mean         0.0003
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     w=1/(\s^2^(F)+0.0001F^2^)
_refine_ls_weighting_scheme      sigma
_refine_ls_wR_factor_gt          0.0222
_refine_ls_wR_factor_ref         0.0229
_reflns_number_gt                2822
_reflns_number_total             3215
_reflns_threshold_expression     I>3\s(I)
_cod_data_source_file            xk5017sup1.cif
_cod_data_source_block           alpha1_zn2p2o7
_cod_original_sg_symbol_H-M      I2/c
_cod_database_code               2310787