Hyperbolic Lone Pair Structure in RhBi4

Two catena‐like interpenetrating enantiomorphic frameworks of condensed tetragonal antiprisms, RhBi 8/2 , form the basis of the crystal structure of RhBi 4 . The electron localization function (ELF) shows high localization of the valence electrons only on the periphery of the frameworks (lone pairs of Bi atoms), whereas the electrons inside the nets are delocalized. The periodic nodal surface (PNS) I 2 ‐Y ** describes perfectly the hyperbolic organization of the entire RhBi 4 structure. It separates the regions with low electron localization inside the polyhedral nets from the hyperbolic layer of the lone pairs.