Sb4

Sb4 refers to a neutral molecular cluster composed of four antimony atoms. It is a member of the family of small pnictogen clusters studied in gas phase, matrix isolation, and materials contexts.

The most discussed structural motif for the neutral Sb4 is a tetrahedral arrangement, with each corner occupied by an Sb atom and connected by Sb–Sb bonds. However, theoretical work has proposed that Sb4 can adopt distorted or alternative isomeric forms depending on charge state, spin, and environment. Bonding in such heavy-element clusters often involves multicenter interactions and delocalized electrons, with relativistic effects contributing to the bonding characteristics.

Sb4 has been produced transiently in the gas phase, for example by laser ablation of bulk antimony or other high-energy methods, and detected using techniques such as mass spectrometry and photoelectron spectroscopy. In matrix isolation experiments, Sb4 can be stabilized at low temperatures for spectroscopic study.

Computational studies, including ab initio and density functional theory calculations, have explored possible geometries, electronic states, and relative energies of Sb4 isomers. Results indicate sensitivity to the level of theory, with the ground-state structure and preferred symmetry varying across methods.

Relevance and outlook: Sb4 serves as a basic building block in the broader study of antimony clusters and nanostructures, contributing to understanding of bonding, growth, and properties of Sb-containing materials.

See also: Sb2, Sb3, Sb4^−, antimony clusters.