On the application of phase relationships to complex structures. XIV. The additional use of statistical information in tangent-formula refinement

Suitable weighting schemes for use in tangent-formula phase development and refinement are discussed, and a statistically based weighting scheme, which can easily be incorporated in existing computer programs, is proposed. Examples of the use of this method in structure solution and completion are presented for a previously unknown structure and for several structures which had been difficult to solve by other methods. In addition a method is given for subtracting the contribution of heavy atoms from observed |E| values on a statistical basis which is very useful when the presence of such atoms leads to problems in defining the enantiomorph. These methods add greatly to the power of the MUL TAN computer program.