Acta Cryst. (2004). E60, i80-i81  [ doi:10.1107/S1600536804011900 ]

The ammonium chromium(III) alum NH₄Cr(SO₄)₂·12H₂O

N. Rempfer, H.-W. Lerner and M. Bolte

Online 5 June 2004

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean (S-O) = 0.001 Å
• R factor = 0.019
• wR factor = 0.051
• Data-to-parameter ratio = 12.3

checkCIF/PLATON results

No syntax errors found




Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....         S1     
PLAT417_ALERT_2_C Short Inter D-H..H-D       H3B    ..  H4A     ..       2.10 Ang.  

Alert level G
FORMU01_ALERT_1_G  There is a discrepancy between the atom counts in the
            _chemical_formula_sum and _chemical_formula_moiety. This is
            usually due to the moiety formula being in the wrong format.
            Atom count from _chemical_formula_sum:   H28 Cr1 N1 O20 S2
            Atom count from _chemical_formula_moiety:H16 N1 O14 S2
REFLT03_ALERT_1_G ALERT: Expected hkl max differ from CIF values
           From the CIF: _diffrn_reflns_theta_max           27.72
           From the CIF: _reflns_number_total                714
           From the CIF: _diffrn_reflns_limit_ max hkl   15.    3.   15.
           From the CIF: _diffrn_reflns_limit_ min hkl  -12.  -14.  -15.
           TEST1: Expected hkl limits for theta max
           Calculated maximum hkl   16.   16.   16.
           Calculated minimum hkl  -16.  -16.  -16.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

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

Copyright © International Union of Crystallography
IUCr Webmaster