The reliability index R₂ as a versatile tool in structure analysis of inorganic and small molecular compounds

Applications of in small-molecule crystallography are described. Ways of using to evaluate initial models of a structure are discussed. These models, obtained from Patterson methods, are usually small. They may include one or more heavy atoms and pseudosymmetry is sometimes present in the model. The criterion is used also to identify misplaced atoms prior to the start of the expansion process. Finally, is used during structure expansion by the application of phase refinement or Fourier methods. Details of the procedures of extension, as well as the role of therein, are presented and evaluated. Results obtained with various test structures are discussed.