The potential energy surface and superatomic properties of the octahedral PtSn5 cluster.

Zintl (group IV elements) clusters with a special number of valence electrons often exhibit extraordinary structures and chemical bonding patterns, and the stability of them is rationalised by the Wade-Mingos rule. However, this rule is still limited for some Zintl clusters. Here, we find that the potential energy surface of PtSn₅ has a single deep funnel, which leads down to the octahedron of the global minimum. The AIMD simulations demonstrate that the octahedral PtSn₅ still has a good thermal stability at 1000 K. The molecular orbitals and AdNDP analyses reveal that the 20 valence electrons from five Sn atoms of the PtSn₅ fill superatomic shells resulting in an electronic configuration of 1S²1P⁶1D¹⁰2S², and the electronic structure of the Pt atom is d¹⁰, well following the magic number of the Jellium model. The result is further confirmed by the density of states and the localised orbital locator. After the CO molecule is adsorbed on the PtSn₅, it prefers to be located at the Pt atom. Due to the charge-transfer effect, the C–O bond length and stretching frequency appear to change significantly. Our work opens up the study on the Jellium model for Zintl clusters. [ABSTRACT FROM AUTHOR]