Multi dimensionnal Inorganic Material Design – Multi D-InMaDe

The French « solid state chemistry community » is in a critical position concerning its lowering contribution to the prospection for new inorganic compounds, at the basis of novel properties. This aspect has been largely neglected against more “profitable” studies on dedicated materials : -for energy, -for electronics, for nuclear etc…, which unfortunately essentially consist in optimizing competitive materials, and therefore do not provide new structural architectures, without preconceived ideas about their properties. This national situation is problematic at a multidisciplinary level since chemists, physicists, theoreticians and even industrial partners are penalized in terms of national perspectives.
In this context, our project proposes, via an original predictive approach, to elaborate novel inorganic compounds. Concretely, we aim to design new compounds with 1D, 2D and 3D structures using original building units, consisting in oxo-centered OM4 polyhedrons assembled into a structuring framework, the empty spaces being filled by groups of various natures, for which the structural specificities will be fully rationalized. In that sense, our approach is innovative and placed in the frame of the renewal of inorganic chemistry since the majority of structures predicted up to now were obtained through variable stacking of 2D building blocks.
The meticulous study of numerous new compounds in the Bi2O3-X2O5-MxOy (M= P, V, As…, X= Li, Na, Cu, Co, Ni, Mg, Cd…) chemical system already enriched our experience in this field and opens great perspectives. From a structural point of view, these phases are deduced from one another by the reorganization of secondary building units (based on O(Bi,M)4 tetrahedrons). We evidenced a particular dependence between the nature of the units and the inter-layers space, leading to empirical rules at the basis of the real prediction of new complex structures. Nevertheless, our ambitions concern the extension of this predictive approach to various chemical systems and the “Design” of structures with various dimensionalities (1D to 3D), leading to different expected properties (dielectric, magnetic, optical…). The work consists in the diversification of the building units’ sizes and topologies, in order to enlarge the self-assembly possibilities. This work involves a systematic rationalization of the preexisting phases to evidence the structural analogies and the chemical parameters controlling the final structure. This tedious work is already under progress in the framework of a review article elaboration (ref 21 in the document).
The involved steps (Design/validation/elaboration/structure/properties) integrate the complete solid state chemists’ tools and include the use of structural data banks, DFT based ab initio calculations, diversification of the synthesis methods, diffraction methods and several collaborations for the crystal growth and the characterizations/validations of physico-chemical properties. Here, the originality of our recent electronic microscopy works deserves to be highlighted. Indeed, we have validated the possibility to determine complex structures of the lattice formed by secondary building units O(Bi,M)4 using simple observation/decoding of high resolution imaging. It appears therefore necessary to deepen these studies of high methodological impact.
Finally, by analogy with the various spectacular properties (optical, dielectric, magnetic, ionic conductivity…) of the compounds already initiated in the above cited systems, we pretend to predict and elaborate certain inter-atomic topologies at the basis of targeted physico-chemical.