Acta Cryst. (2005). E61, o2376-o2378  [ doi:10.1107/S1600536805020398 ]

(S)-(+)-2-[2-(Biphenyl-2-yl)-1-methylethyl]-4,5-dihydro-1H-imidazolium hydrogen oxalate

M. Giannella, F. Gentili, B. Bruni, L. Messori and M. Di Vaira

Online 6 July 2005

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean (C-C) = 0.003 Å
• R factor = 0.035
• wR factor = 0.083
• Data-to-parameter ratio = 9.1

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT027_ALERT_3_A _diffrn_reflns_theta_full (too) Low ............      60.54 Deg.  

Alert level B
THETM01_ALERT_3_B  The value of sine(theta_max)/wavelength is less than 0.575
            Calculated sin(theta_max)/wavelength =    0.5647
PLAT023_ALERT_3_B Resolution (too) Low [sin(th)/Lambda < 0.6].....      60.54 Deg.  

Alert level C
PLAT063_ALERT_3_C Crystal Probably too Large for Beam Size .......       0.70 mm    
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.48       
PLAT350_ALERT_3_C Short   C-H Bond (0.96A)   C18    -   H182   ...       0.84 Ang.  
PLAT355_ALERT_3_C Long    O-H Bond (0.82A)   O1     -   H1O    ...       1.01 Ang.  
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C19    -   C20    ...       1.53 Ang.  
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1       
              C18 H21 N2                                                        

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           60.54
           From the CIF: _reflns_number_total               2761
           Count of symmetry unique reflns         1497
           Completeness (_total/calc)            184.44%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1264
           Fraction of Friedel pairs measured     0.844
           Are heavy atom types Z>Si present         no

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

   0 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
   6 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion

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