A series of anions is shown below:

The anion on the far right is called 'BARF' by chemists, as its common abbreviation sounds similar to this word. (b) What is the electron-domain geometry around the central B in BARF?

Key Concepts

Electron-Domain Geometry

Electron-domain geometry refers to the spatial arrangement of electron groups around a central atom in a molecule. These groups can include bonding pairs of electrons, lone pairs, and single electrons. The geometry is determined by the number of these electron groups, which influences the molecular shape and angles between bonds.

VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) theory is a model used to predict the geometry of individual molecules based on the repulsion between electron pairs in the valence shell of the central atom. According to VSEPR, electron pairs will arrange themselves as far apart as possible to minimize repulsion, leading to specific geometrical shapes such as linear, trigonal planar, or tetrahedral.

Central Atom Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate bonding. The type of hybridization (e.g., sp, sp², sp³) of the central atom affects the electron-domain geometry. For example, sp³ hybridization corresponds to a tetrahedral geometry, while sp² leads to trigonal planar geometry, which is crucial for determining the shape of the BARF anion.