Acta Cryst. (2002). E58, i93-i94  [ doi:10.1107/S1600536802016963 ]

Decaammonium dodecatungstate nonahydrate, (NH₄)₁₀[H₂W₁₂O₄₂]·9H₂O: anionic `isomorphism'

G. J. Gainsford, S. V. Chong, B. Ingham and J. L. Tallon

Online 27 September 2002

Key indicators

• Single-crystal X-ray study
• T = 168 K
• Mean (W-O) = 0.012 Å
• H-atom completeness 1%
• Disorder in solvent or counterion
• R factor = 0.051
• wR factor = 0.128
• Data-to-parameter ratio = 28.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level A:



ABSTM_02  Alert A Crystal and compound unsuitable for non-numerical             
          corrections. Product of mu and tmid > 3.0                             
           Value of mu given =    26.200 tmid =     0.140                       

 Alert Level C:



ABSMU_01  Alert C The ratio of given/expected absorption coefficient lies       
          outside the range 0.99 <> 1.01                                        
          Calculated value of mu =    27.155                                    
          Value of mu given      =    26.200                                    

DIFMX_01  Alert C The maximum difference density is > 0.1*ZMAX*0.75             
          _refine_diff_density_max given =      6.040                           
          Test value =      5.550                                               

DIFMX_02  Alert C The minimum difference density is > 0.1*ZMAX*0.75             
          The relevant atom site should be identified.                          

PLAT_202  Alert C Isotropic non-H Atoms in Anion/Solvent       =         33

PLAT_302  Alert C Anion/Solvent Disorder .......................       3.00 Perc.

General Notes



FORMU_01  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:H60 N10 O51 W12                 
          Atom count from the _atom_site data:  N10 O51 W12                     

CELLZ_01                                                                        
         From the CIF: _cell_formula_units_Z    2                               
         From the CIF: _chemical_formula_sum  H60 N10 O51 W12                   
         TEST: Compare cell contents of formula and atom_site data              
                                                                                
         atom    Z*formula  cif sites diff                                      
         H        120.00      0.00  120.00                                      
         N         20.00     20.00    0.00                                      
         O        102.00    102.00    0.00                                      
         W         24.00     24.00    0.00                                      
          Difference between formula and atom_site contents detected.           
          WARNING: H atoms missing from atom site list. Is this intentional?    

CHEMW_03                                                                        
         From the CIF: _cell_formula_units_Z                    2               
         From the CIF: _chemical_formula_weight          3222.78                
         TEST: Calculate formula weight from _atom_site_*                       
         atom     mass    num     sum                                           
         O        16.00   51.00  815.95                                         
         H         1.01    0.00    0.00                                         
         N        14.01   10.00  140.07                                         
         W       183.85   12.00 2206.20                                         
         Calculated formula weight             3162.22                          
          The ratio of given/expected molecular weight as calculated            
          from the _atom_site* data lies outside                                
          the range 0.99 <> 1.01                                                


 1 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 5 Alert Level C = Please check

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