Volume 2 Chapter 7 Numeric Sub-menu *COORDINATES

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*DENC and *DENX

Function

*DENC and *DENX are used to test for a specified value of the crystal density.

CSD Contents

Two crystal densities may be stored (to 3 decimal places) in a CSD entry :

Dx : calculated density reported by the authors *DENX

Dc : density calculated at the CCDC *DENC

If Dx is not reported then value of 0.0 is stored in the CSD.

Graphics QUEST3D Procedure

Select *DENC or *DENX from the NUMERIC sub-menu and respond to the standard numeric prompts.

Basic QUEST Procedure

Ex.1

T1 *DENC 2.5 - 2.8

This will register hits for all entries having Dc in the range 2.5-2.8 g.cm-3

Ex.2

T1 *DENC 0.01 - 0.80

This will register hits for all entries having Dc in the range 0.01-0.80 g.cm-3

Example 2 emphasises the fact that if we search for low values then we must use the range feature rather than .LE. 0.80 because missing values are recorded as 0.0 and these would also be registered as hits.

Remarks

Often there are errors in Dx. The most reliable density record is the value of Dc.

The *DENM test (for measured density) was discontinued in October 1997.

Related Keywords

*ZVALUE, *ZPRIME

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Volume 2 Chapter 7 Numeric Sub-menu *INTFLAG.