Sb7

Sb7 denotes a seven-atom cluster composed of antimony atoms (Sb). In chemistry it is studied as a molecular cluster and as a structural unit in solid-state compounds. Sb7 can exist in neutral form or as anions, notably [Sb7]3− or [Sb7]2−, depending on the surrounding counterions and synthesis conditions.

In the gas phase, Sb7 clusters have been observed and characterized by mass spectrometry and photoelectron spectroscopy, formed by laser ablation or thermal evaporation of antimony powders. In condensed phases, Sb7 units appear in Zintl-phase materials and in intercalation compounds with alkali metals, often as part of larger polyantimony frameworks. They are typically prepared by chemical reduction of antimony sources with alkali metals or by condensation of antimony-containing species in suitable solvents.

Structural studies show multiple motifs; the exact geometry depends on charge state and environment. Proposed structures range from a central Sb coordinating six neighbors to cage-like or distorted polyhedral arrangements, all featuring multicenter Sb–Sb interactions and delocalized bonding. Characterization relies on X-ray diffraction for solid samples and computational methods for gas-phase ions.

Sb7 provides insight into main-group cluster chemistry and Zintl phases, illustrating how small clusters relate to extended antimony-rich solids. It is of interest to researchers studying electron-rich pnictogen clusters and nanoscale materials. See also antimony; Zintl phase; polyantimony clusters.