Chemical Bonding & Molecular Structure

The donation of electron density from a filled orbital on one atom into an empty orbital on its bonded partner, in the direction opposite…

M(dπ) → L(π*) kJ/mol

A molecular shape in which two bonded atoms form an angle at a central atom that also carries one or more lone pairs.

AX₂E or AX₂E₂ degrees

Chemical Bonding & Molecular Structure

The angle between two bonds that share a common atom.

degrees

Chemical Bonding & Molecular Structure

The energy required to break one mole of a given bond homolytically in the gaseous state.

A–B(g) → A(g) + B(g) kJ/mol

Chemical Bonding & Molecular Structure

The equilibrium distance between the nuclei of two bonded atoms.

d ≈ r₁ + r₂ pm

Chemical Bonding & Molecular Structure

The number of chemical bonds between a pair of atoms, or in molecular orbital terms half the difference between bonding and antibonding…

BO = (N_b − N_a) / 2 Dimensionless

Chemical Bonding & Molecular Structure

The degree of unequal electron sharing in a covalent bond, arising from an electronegativity difference between the bonded atoms.

Δχ = |χ_A − χ_B| Dimensionless

Chemical Bonding & Molecular Structure

A molecular orbital lower in energy than the atomic orbitals from which it forms, whose occupation stabilises the molecule.

ψ = ψ_A + ψ_B Dimensionless

Chemical Bonding & Molecular Structure

A pair of electrons shared between two atoms and responsible for holding them together.

Dimensionless

Chemical Bonding & Molecular Structure

A thermochemical cycle applying Hess's law to determine the lattice energy of an ionic compound indirectly.

ΔH_f = ΔH_sub + IE + ½D + EA + U kJ/mol