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*SPACEGROUP

Function

*SPACEGROUP is used to test for a specified space group symbol.

CSD Contents

Space group symbols are recorded in the Hermann-Mauguin notation used in International Tables for Crystallography. They are listed in Appendix 6.

Graphics QUEST3D Procedure

Select *SPAC from the TEXT sub-menu and respond to the standard text prompts.

Basic QUEST Procedure

Ex.

T1 *SPAC A2/m

This will register hits for all entries having space group symbol A2/m.

Ex.

T1 *SPAC 'P21^'            where ^ is blank

This will register hits for all entries having space group symbol P21.

In the second example we enclose the symbol within ' marks and leave a blank space after 1

Since *SPACEGROUP involves a text search of a left-adjusted field this ensures that hits are registered only for P21 and not for P21/c, P212121, etc.

Related Bit Screens

A number of bit screens can be used to search for various categories of space groups:

94

space group is completely defined

95

space group is partially defined

96

space group is not known

97

space group is centrosymmetric

98

space group is non-centrosymmetric

99

space group origin is at a centre of symmetry; atomic coordinates are present

100

space group origin is not at a centre of symmetry; atomic coordinates are present

101

space group is a Sohncke group ie. only symmetry elements are rotation and screw axes

Ex.

SCRE  101

This query screen registers hits for all entries where the space group is a Sohncke group.

For screen 95 an aspect symbol replaces the full space group symbol.

Aspect symbols have numbers greater than 500 (see Appendix 7). Entries involving aspect symbols generally correspond to conference abstracts when the space group has not been fully determined.

Related Keywords

*SPGNUMBER

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Volume 2 Chapter 11 Text Menu Standard Text Prompts.