Chemical Bonding & Molecular Structure
10 terms
Back Bonding
Chemical Bonding & Molecular Structure
kJ/mol
The donation of electron density from a filled orbital on one atom into an empty orbital on its bonded partner, in the direction opposite to the sigma bond.
M(dπ) → L(π*)
Bent Geometry
Chemical Bonding & Molecular Structure
degrees
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
Bond Angle
Chemical Bonding & Molecular Structure
degrees
The angle between two bonds that share a common atom.
Bond Energy
Chemical Bonding & Molecular Structure
kJ/mol
The energy required to break one mole of a given bond homolytically in the gaseous state.
A–B(g) → A(g) + B(g)
Bond Length
Chemical Bonding & Molecular Structure
pm
The equilibrium distance between the nuclei of two bonded atoms.
d ≈ r₁ + r₂
Bond Order
Chemical Bonding & Molecular Structure
Dimensionless
The number of chemical bonds between a pair of atoms, or in molecular orbital terms half the difference between bonding and antibonding electrons.
BO = (N_b − N_a) / 2
Bond Polarity
Chemical Bonding & Molecular Structure
Dimensionless
The degree of unequal electron sharing in a covalent bond, arising from an electronegativity difference between the bonded atoms.
Δχ = |χ_A − χ_B|
Bonding Molecular Orbital
Chemical Bonding & Molecular Structure
Dimensionless
A molecular orbital lower in energy than the atomic orbitals from which it forms, whose occupation stabilises the molecule.
ψ = ψ_A + ψ_B
Bonding Pair
Chemical Bonding & Molecular Structure
Dimensionless
A pair of electrons shared between two atoms and responsible for holding them together.
Born–Haber Cycle
Chemical Bonding & Molecular Structure
kJ/mol
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