Polyhedra are prevalent in crystallography; we seek to rationalise structures in terms of tetrahedra, octahedra and other regular shapes. Indeed, many structure-property relationships can be described in terms of interactions between rigid coordination spheres, such as perovskite phase transitions and negative thermal expansion. Often, however, polyhedra are not rigid instead displaying some degree of distortion; analysing this can be difficult, particularly if the polyhedron shows deviations both in terms of both bond lengths and angles. Often, these distortions can give rise to complex electronic effects, resulting in useful magnetic materials. While local symmetry mode analysis can give a comprehensive structural picture in many cases, it is often difficult to interpret if multiple distortion modes act cooperatively. Alternatively, continuous shape measures [1] can be used to quantify deviations from a reference polyhedron, but this reference is not always trivial to define. Here, we present a much simpler measure of polyhedron distortion, based on the fitting of ellipsoids to coordination environments. We have applied this new general method to a range of metal oxide materials, revealing new insights into their properties; from a switching bistability in symmetry-disallowed perovskite phase transitions to a weak off-centre 'd5-effect' for Fe3+ ions, that could potentially be exploited in multiferroic materials.[2] We have implemented the method in the python package PIEFACE. While the method has currently been applied to metal oxides, it could easily be generalised to other materials that obey a polyhedral description, including coordination complexes, framework materials and organic molecules.

Too many chemistry jou• rnals*SIR: We are writing to communicate to our colleagues our joint concern over the recent proliferation of journals in chemistry.We shall not discuss the overall growth in the number of papers published. That is another matter. We are concerned here with the quality of the literature, its cost to the libraries of our institutions, and how publication is organized.1) Today a publisher can start a journal in almost any part of chemistry and, by charging a high subscription price, can apparently make a profit, relying only on sale to libraries. The libraries are a captive market. They have assumed that they must buy every journal published irrespective of its overall quality.2) The new journals generally do not require publication charges from the authors, but subsist on the high subscription prices. In some countries the result of increased publication in these journals is a general shift of the burden of supporting publication from the government agencies (which generally pay the researchers' publication charges) to universities (which support the libraries). In other countries money, which the universities could otherwise use for research, goes to meet the blownup library costs. The budgets of university library systems are overburdened. Several libraries have had to institute a freeze on the ordering of new •Reprinted from Chemical & Engineering NeW8, December 10, 1973 by permission of copyright owner, the American Chemical Society .

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