Diamond 2.1: Investigation of coordination spheres
Diamond 2.1 Features Overview...
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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.
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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).
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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
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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...
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