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Diamond 2.1: Investigation of coordination spheres

Diamond 2.1 Features Overview...
Previous: Molecules and packing diagrams...
Next: Versatile use of polyhedra...

Molecules can easily be built from the atoms of the parameter list. Symmetry operations are invoked automatically, if the atoms in the parameter list do not describe an entire molecule. To generate a packing diagram, you may start creating all or a portion of atoms within a given cell range, e.g. the unit cell, then call the Complete Fragments function to get entire molecules. 

Keggin structure (aquaoxoniumdodecatungstophosphate)

Coordination spheres (whose sizes derive from bonding spheres) as well as arbitrary spheres of fixed size can easily be checked by Diamond and used, e.g. to create all or selected atoms within those spheres with or without polyhedron faces.

The picture on the right demonstrates how the coordination spheres can be checked and how the P-O-tetrahedra and distorted W-O-octahedra are linked in the Keggin structure (aquaoxoniumdodecatungstophosphate).

Steps to build up Keggin structure picture

The second picture shows three steps of the creation of that scenery. First the creation of a central P atom. Second the completion of the tetrahedral environment, here symbolized by a transparent polyhedron. Third the generation of the W atoms connected with the four O atoms of the central tetrahedron. The first picture is then completed by generation of W-O-octahedra.

The following list of distances (in Angstroems) from P and W, rsp., to O is taken from Diamond's tabular output of distances and/or angles. Together with the histogram in the Connectivity dialog, you can use that output to control the distances and angles within coordination or arbitrary spheres.

        P 1   O 1   1.571
        O 1         1.571	
        O 1         1.571	
        O 1         1.571	
        W 1   O 4   1.757	
        O 2         1.958	
        O 2         1.958	
        O 3         1.964	
        O 3         1.964	
        O 1         2.507	

Reference:

ICSD Collection Code 908:
Name: Aquaoxonium dodecatungstophosphate
Formula: (H5O2)3PW12O40
Author(s): Brown G M, Noe-Spirlet M R, Busing W R, Levy H A
Title: Dodecatungstophosphoric acid hexahydrate, (H5O2)3PW12O40, the true structure of Keggin's 'pentahydrate' from single crystal X-ray and neutron diffraction data
Journal: ACBCA 33 (1977), pp. 1038 - 1046


Diamond 2.1 Features Overview...
Previous: Molecules and packing diagrams...
Next: Versatile use of polyhedra...