Acta Cryst. (2009). E65, i4-i5  [ doi:10.1107/S1600536808042499 ]

Ammonium iron(III) phosphate(V) fluoride, (NH₄)_0.5[(NH₄)_0.375K_0.125]FePO₄F, with ammonium partially substituted by potassium

L. Wang, Y. Zhou, Y.-X. Huang and J.-X. Mi

Online 20 December 2008

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean (P-O) = 0.004 Å
• H-atom completeness 58%
• Disorder in main residue
• R factor = 0.031
• wR factor = 0.054
• Data-to-parameter ratio = 13.9

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT073_ALERT_1_A H-atoms ref, but _hydrogen_treatment reported as     constr     

Alert level B
PLAT112_ALERT_2_B ADDSYM Detects Additional (Pseudo) Symm. Elem...          n     
PLAT112_ALERT_2_B ADDSYM Detects Additional (Pseudo) Symm. Elem...          n     
PLAT430_ALERT_2_B Short Inter D...A Contact  O1     ..  N1      ..       2.83 Ang. 
PLAT430_ALERT_2_B Short Inter D...A Contact  O4     ..  N1      ..       2.75 Ang. 
PLAT430_ALERT_2_B Short Inter D...A Contact  O5     ..  N1      ..       2.74 Ang. 
PLAT431_ALERT_2_B Short Inter HL..A Contact  F1     ..  N1      ..       2.70 Ang. 
PLAT115_ALERT_5_B ADDSYM Detects Noncrystallographic Inversion ...         93 PerFi

Alert level C
            Value of measurement temperature given =   173.000
            Value of melting point given =     0.000
SHFSU01_ALERT_2_C  Test not performed. _refine_ls_shift/su_max and
            _refine_ls_shift/esd_max not present.
            Absolute value of the parameter shift to su ratio given   0.001
PLAT301_ALERT_3_C Main Residue  Disorder .........................       1.00 Perc.
PLAT430_ALERT_2_C Short Inter D...A Contact  O7     ..  N1      ..       2.89 Ang. 
PLAT034_ALERT_1_C No Flack Parameter Given. Z .GT. Si, NonCentro .          ?
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       0.25 Ratio
PLAT068_ALERT_1_C Reported F000 Differs from Calcd (or Missing)...          ?

Alert level G
FORMU01_ALERT_2_G  There is a discrepancy between the atom counts in the
            _chemical_formula_sum and the formula from the _atom_site* data.
            Atom count from _chemical_formula_sum:H7 F2 Fe2 K0.25 N1.75 O8 P2
            Atom count from the _atom_site data:  H4 F2 Fe2 K0.249 N1.75 O8 P2
CELLZ01_ALERT_1_G Difference between formula and atom_site contents detected.
CELLZ01_ALERT_1_G WARNING: H atoms missing from atom site list. Is this intentional?
           From the CIF: _cell_formula_units_Z    4
           From the CIF: _chemical_formula_sum  F2 Fe2 H7 K0.25 N1.75 O8 P2
           TEST: Compare cell contents of formula and atom_site data

           atom    Z*formula  cif sites diff
           F          8.00      8.00    0.00
           Fe         8.00      8.00    0.00
           H         28.00     16.00   12.00
           K          1.00      1.00    0.00
           N          7.00      7.00    0.00
           O         32.00     32.00    0.00
           P          8.00      8.00    0.00
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           32.53
           From the CIF: _reflns_number_total               2162
           Count of symmetry unique reflns         1683
           Completeness (_total/calc)            128.46%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       479
           Fraction of Friedel pairs measured     0.285
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          5      

   1 ALERT level A = In general: serious problem
   7 ALERT level B = Potentially serious problem
   7 ALERT level C = Check and explain
   5 ALERT level G = General alerts; check

   7 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   9 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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