Structural geomimetism:: A conceptual framework for devising new materials from first principles

We propose an original conceptual framework for the search for new materials based on "structural geomimetism". Specific properties can be sought such as artificially derived new hard materials as well as mixed anion systems. The results on binary C3N4 and C11N4 on one hand and ternary BC2N systems on the other hand represent the two major parts of this review work. Further we introduce the different approaches to hardness as well as a brief introduction to the methodology of the density functional theory (DFT) and some of its methods. Their use for identifying the optimum structures and their mechanical properties (equation of state, EOS) and for examining electronic structure (density of states, DOS; chemical bonding, COOP; electron localization function. ELF) is extensively illustrated. The spectroscopic properties meant to bring a tool of signature for distinguishing phases in polymorphic samples are provided with ELNES spectra. (C) 2006 Elsevier Ltd. All rights reserved.