crystalmaker highlight polyhedra withour central atom

This has been extensively studied in some cases. Thus, in the quest for new materials, understanding the structures that result from mixing simpler compounds to form more complex materials is critical. 6 By expanding the chemical space in which compound discovery can occur by considering mixed oxides, the potential for materials discovery expands exponentially. Such multicomponent oxides often have significantly improved performance over the end-member compounds, with enhanced scintillation, 1 ferroelectricity, 2, 3 piezoelectricity, 4 high temperature stability 5 and catalytic response. Indeed, beyond base compounds such as binaries and ternaries, the possibilities for modifying the chemistry of most oxides is nearly limitless. This richness arises from the very flexible chemistry of these materials. Oxides are an attractive class of materials due to their extreme variety in functionality. Implications of our findings are discussed in relation to the observed composition-dependent ionic conductivity in these systems and connections with previously reported experimental findings are made. Subsequently, we examine the stability of this type of ordering in 131 other pyrochlore compositions. The origins of these anomalous oxygen relaxations are traced back to both the local cation symmetry and a strong chemical preference of Zr atoms towards adopting a 7-fold coordination environment, as opposed to a 6-fold coordination available in a regular pyrochlore structure. Our results show that, in the presence of some very specific local cation arrangements, certain cation-ordered compositions in this system are highly stabilized as a result of large oxygen relaxation displacements, leading to the formation of an ordered ‘double’ pyrochlore structure. Here, we examine relative stability of different cation orderings in one model double pyrochlore Gd 2(Zr xTi 1− x) 2O 7, as a function of Zr content x. Mixed pyrochlores-containing two A and/or two B site cations-provide even more flexibility for tailoring properties owing to the diverse chemical and configurational degrees of freedom accessible within this chemical space. Pyrochlore oxides (A 2B 2O 7) are interesting for a number of technological applications, including radiation damage tolerance and as ionic conductors.

Crystalmaker highlight polyhedra withour central atom