data_2003248
_publ_section_title
;
Strontium Diiron(III) Pyrophosphate
;
_journal_name_full               'Acta Crystallographica C'
_journal_page_first              346
_journal_page_last               348
_journal_volume                  51
_journal_year                    1995
_chemical_compound_source
;
SrFe(III)~2~(P~2~O~7~)~2~ has been synthesized by
mixing stoichiometric amounta of (NH~4~)~2~HPO~4~, SrCO~3~ and
Fe~2~O~3~ according to the following equation:
SrCO~3~ + 4(NH~4~)~2~HPO~4~ + Fe~2~O~3~ => SrFe~2~(P~2~O~7~)~2~ +
8NH~3~ + CO~2~ + 6H~2~O
After grinding, the mixture was heated progressively to 1243 K. The final
heating was followed by a return to room temperature in air.
Single crystals were prepared by grinding and heating an
appropriate mixture of material to 1275 K.
After 24 h at this temperature, the melt was cooled  (5 K h^-1^)
allowing the isolation of grey crystals.
;
_chemical_formula_moiety         'Fe2 O14 P4 Sr1'
_chemical_formula_sum            'Fe2 O14 P4 Sr'
_chemical_formula_weight         547.2
_symmetry_space_group_name_H-M   'P -1'
_cell_angle_alpha                89.83(3)
_cell_angle_beta                 87.59(3)
_cell_angle_gamma                73.11(3)
_cell_formula_units_Z            1
_cell_length_a                   4.795(1)
_cell_length_b                   7.108(1)
_cell_length_c                   7.830(2)
_cell_measurement_reflns_used    45
_cell_measurement_temperature    298
_cell_measurement_theta_max      17.0
_cell_measurement_theta_min      10.0
_cell_volume                     255.13(9)
_diffrn_measurement_device       'Syntex P4 4-circle'
_diffrn_measurement_method       \q/2\q
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0178
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -1
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            1966
_diffrn_reflns_theta_max         30
_diffrn_standards_decay_%        0.0001
_diffrn_standards_interval_count 97
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    8.731
_exptl_absorpt_correction_T_max  0.37
_exptl_absorpt_correction_T_min  0.12
_exptl_absorpt_correction_type   semi-empirical
_exptl_crystal_colour            grey
_exptl_crystal_density_diffrn    3.561
_exptl_crystal_description       chunk
_exptl_crystal_size_max          0.3
_exptl_crystal_size_mid          0.3
_exptl_crystal_size_min          0.3
_exptl_crystal_thermal_history
'heated progressively to 1243 K; heating an appropriate mixture of material to 1275 K'
_refine_diff_density_max         1.41
_refine_diff_density_min         -0.85
_refine_ls_goodness_of_fit_obs   1.13
_refine_ls_number_parameters     101
_refine_ls_number_reflns         1247
_refine_ls_R_factor_obs          .0378
_refine_ls_shift/esd_max         0.001
_refine_ls_structure_factor_coef F
_refine_ls_weighting_scheme      'w = 1/[\s^2^(F)+ 0.0008F^2^]'
_refine_ls_wR_factor_obs         .0463
_reflns_number_observed          1247
_reflns_number_total             1483
_reflns_observed_criterion       F>4.0\s(F)
_[local]_cod_chemical_formula_sum_orig 'Fe2 O14 P4 Sr1'
loop_
_symmetry_equiv_pos_as_xyz
x,y,z
-x,-y,-z
loop_
_atom_type_symbol
_atom_type_scat_source
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
Fe 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 0.4 1.0
Sr 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' -1.4 3.6
P 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 0.1 0.2
O 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 0.0 0.0
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Sr1 0.500 0. 0. 0.027(1)
Fe1 0.5000 0. 0.5000 0.017(1)
Fe2 0. 0.5000 0. 0.018(1)
P1 0.1184(2) -0.2307(2) 0.2988(1) 0.018(1)
P2 0.5346(2) -0.6203(2) 0.2454(1) 0.017(1)
O11 -0.1208(7) -0.1804(4) 0.4337(4) 0.022(1)
O12 0.3199(7) -0.0993(4) 0.2933(4) 0.021(1)
O13 0.0124(7) -0.2412(4) 0.1169(4) 0.020(1)
O14 0.3104(7) -0.4469(4) 0.3504(4) 0.021(1)
O21 0.8114(7) -0.5653(5) 0.2077(4) 0.022(1)
O22 0.5887(7) -0.8062(4) 0.3457(4) 0.024(1)
O23 0.3844(7) -0.6478(4) 0.0818(4) 0.020(1)
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_22
_atom_site_aniso_U_23
_atom_site_aniso_U_33
Sr1 0.034(1) -0.005(1) 0.000(1) 0.019(1) -0.001(1) 0.026(1)
Fe1 0.018(1) -0.005(1) -0.001(1) 0.017(1) 0.000(1) 0.017(1)
Fe2 0.017(1) -0.005(1) -0.002(1) 0.019(1) 0.000(1) 0.018(1)
P1 0.017(1) -0.004(1) -0.001(1) 0.017(1) -0.002(1) 0.018(1)
P2 0.017(1) -0.005(1) -0.002(1) 0.016(1) 0.000(1) 0.018(1)
O11 0.019(1) -0.003(1) 0.000(1) 0.023(1) 0.000(1) 0.022(1)
O12 0.022(1) -0.008(1) 0.000(1) 0.022(1) -0.004(1) 0.020(1)
O13 0.020(1) -0.004(1) -0.004(1) 0.019(1) 0.000(1) 0.020(1)
O14 0.019(1) -0.002(1) -0.001(1) 0.020(1) -0.001(1) 0.022(1)
O21 0.021(1) -0.0011(1) -0.002(1) 0.027(1) 0.001(1) 0.021(1)
O22 0.024(2) -0.004(1) 0.000(1) 0.018(1) 0.005(1) 0.027(1)
O23 0.018(1) -0.004(1) -0.002(1) 0.021(1) -0.004(1) 0.021(1)
