Acta Cryst. (2002). E58, i70-i71  [ doi:10.1107/S1600536802011868 ]

Samarium orthosilicate oxyapatite, Sm₅(SiO₄)₃O

M. G. Morgan, M. Wang and A. Mar

Online 12 July 2002

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean (Si-O) = 0.008 Å
Some non-H atoms missing
• R factor = 0.031
• wR factor = 0.074
• Data-to-parameter ratio = 17.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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:O13 Si3 Sm5                     
          Atom count from the _atom_site data:  O43 Si3 Sm5                     

CELLZ_01                                                                        
         From the CIF: _cell_formula_units_Z    2                               
         From the CIF: _chemical_formula_sum  O13 Si3 Sm5                       
         TEST: Compare cell contents of formula and atom_site data              
                                                                                
         atom    Z*formula  cif sites diff                                      
         O         26.00     86.00  -60.00                                      
         Si         6.00      6.00    0.00                                      
         Sm        10.00     10.00    0.00                                      
          Difference between formula and atom_site contents detected.           
          ALERT: Large difference may be due to a                               
          symmetry error - see SYMMG tests                                      

CHEMW_03                                                                        
         From the CIF: _cell_formula_units_Z                    2               
         From the CIF: _chemical_formula_weight          1044.02                
         TEST: Calculate formula weight from _atom_site_*                       
         atom     mass    num     sum                                           
         O        16.00   43.00  687.96                                         
         Si       28.09    3.00   84.26                                         
         Sm      150.36    5.00  751.80                                         
         Calculated formula weight             1524.01                          
          ALERT: The ratio of given/expected molecular weight as calculated     
          from the _atom_site* data lies outside                                
          the range 0.90 <> 1.10                                                

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