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Some recent examples of substitution effects in the three partial structures of selected socialites are presented. Framework-cation, and cage-cation substitution effects are discussed for the series vertical bar(Eu(x)Ca(2-x))(4)(OH)(8)vertical bar[(Al(2+x)Si(1-x))(4)O(24)]-SOD, cage-anion substitutions for vertical bar Ca(8)[(WO(4))(x)(MoO(4))(1-x)](2)vertical bar[Al(2)O(24)]-SOD. While in a first approximation decomposition into partial structures seems reasonable, it is shown that, however, effects arising from substitutions in one partial structure are not limited to it. This is due to the fact that three main interactions have to be considered, namely, cage-cation - framework, cage-anion - framework, and cage-cation - cage-anion interactions. These can be co-operative or competitive and may lead to structural frustrations. (C) 2009 Published by Elsevier Ltd.

There has been a considerable amount of interest in negative thermal expansion (NTE) phases which are of importance, for example, in the manufacture of low or zero expansion composite materials. Cu...

We show that silver(I) hexacyanocobaltate(III), Ag3[Co(CN)6], exhibits positive and negative thermal expansion an order of magnitude greater than that seen in other crystalline materials. This framework material expands along one set of directions at a rate comparable to the most weakly bound solids known. By flexing like lattice fencing, the framework couples this to a contraction along a perpendicular direction. This gives negative thermal expansion that is 14 times larger than in ZrW2O8. Density functional theory calculations quantify both the low energy associated with this flexibility and the role of argentophilic (Ag+...Ag+) interactions. This study illustrates how the mechanical properties of a van der Waals solid might be engineered into a rigid, useable framework.

The structure of Fe0.47NbS2 was refined in the space group P6322 (hexagonal, a = 5.7905(2) A and c = 12.3891(2) A) [L. Ehm, S. Vogel, K. Knorr, P. Schmid-Beurmann, W. Depmeier, J. Alloys Comp. 339 (2002) 30–34]; it is described more adequately in P63/mmc with a smaller unit cell. Revised coordinates are given.