Lord, EA and Ranganathan, S (2004) The \gamma-brass structure and the Boerdijk–Coxeter helix. In: Journal of Non-Crystalline Solids, 334-33 . pp. 121-125.
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The \gamma-brass structure was for a long time regarded as a modified bcc structure. It is more accurately described in terms of a 26-atom cluster consisting of four interpenetrating icosahedral clusters. An alternative description in terms of a 38-atom cluster is also illuminating. We discuss the \gamma-brass structure in terms of the packing of spheres and the packing of 'almost regular’ tetrahedra and demonstrate a close relationship to the helical sphere packings investigated by Boerdijk, who considered the configuration of touching spheres centred at the vertices of a Coxeter helix, and extended it by adding an extra layer of spheres. Adding a further layer of spheres gives a rod-like structure in which every sphere of the original helix is surrounded by twelve others, configured as a somewhat distorted icosahedron. Thus each tetrahedron of the initial structure is then shared by four icosahedra. This 26-sphere cluster is a slightly distorted form of the 26-atom \gamma-brass cluster.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier.|
|Department/Centre:||Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)|
|Date Deposited:||30 Nov 2007|
|Last Modified:||19 Sep 2010 04:36|
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