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On the Application of Direct Methods in X‐Ray Structure Analysis: Survey on Number and Kind of Solved Acentric Equal Atom Structures
Author(s) -
Messerschmidt J.
Publication year - 1979
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19790140917
Subject(s) - acentric factor , atom (system on chip) , space (punctuation) , mathematics , unit (ring theory) , direct methods , group (periodic table) , crystallography , combinatorics , physics , chemistry , computer science , quantum mechanics , mathematics education , embedded system , operating system
A statistical analysis of all acentric equal atom structures solved by direct methods and reported in Acta Crystallographica from January 1968 to November 1978 has been carried out. The most frequently applied direct methods programs are the MULTAN, SAP and SHELX. About 80% of all considered structures belong to the space groups P2 1 2 1 2 1 and P 2 1 . Problems with direct methods can arise if the number of the nonhydrogen atoms per asymmetric unit is greater then about 40 and/or the space group belongs to a category in which the definition of the enantiomorph is difficult.