Inorganic & Coordination Chemistry — 60 Terms Defined

Alloy Inorganic & Coordination Chemistry Dimensionless A metallic material made by combining a metal with one or more other elements.

Ambidentate Ligand Inorganic & Coordination Chemistry Dimensionless A monodentate ligand possessing two different potential donor atoms, either of which may bind.

Bidentate Ligand Inorganic & Coordination Chemistry Dimensionless A ligand that binds to the same metal centre through two donor atoms, forming a ring.

Central Metal Atom Inorganic & Coordination Chemistry Dimensionless The metal atom or ion at the heart of a coordination entity, which accepts electron pairs from the ligands.

Charge Transfer Spectrum Inorganic & Coordination Chemistry nm An intense absorption produced when an electron moves between metal and ligand orbitals.

Chelate Inorganic & Coordination Chemistry Dimensionless A cyclic complex formed when a multidentate ligand grips a metal ion through two or more donor atoms.

Chelate Effect Inorganic & Coordination Chemistry kJ/mol The greater stability of a complex containing a multidentate ligand compared with one containing equivalent monodentate ligands. ΔS favourable

Complex Ion Inorganic & Coordination Chemistry Dimensionless A charged species consisting of a central metal ion surrounded by a definite number of ligands. [ML₆]ⁿ⁺

Coordination Compound Inorganic & Coordination Chemistry Dimensionless A compound containing a central metal atom or ion bonded to surrounding molecules or ions by coordinate bonds. [M(L)ₙ]Xₘ

Coordination Isomerism Inorganic & Coordination Chemistry Dimensionless Isomerism in compounds containing both a complex cation and a complex anion, where ligands are distributed differently between them.

Coordination Sphere Inorganic & Coordination Chemistry Dimensionless The central metal together with the ligands directly attached to it, written inside square brackets. [M(L)ₙ]

Counter Ion Inorganic & Coordination Chemistry Dimensionless An ion outside the coordination sphere that balances the charge of the complex ion.

Crystal Field Splitting Energy Inorganic & Coordination Chemistry cm⁻¹ The energy difference between the sets of d orbitals produced when a ligand field lifts their degeneracy. Δ₀ or Δ_t

Crystal Field Stabilisation Energy Inorganic & Coordination Chemistry kJ/mol The net energy gained by a complex through the preferential occupation of lower-energy d orbitals. CFSE = (−0.4n_t2g + 0.6n_eg)Δ₀

Crystal Field Theory Inorganic & Coordination Chemistry kJ/mol The model treating metal–ligand bonding as purely electrostatic and analysing how ligand fields split the metal d orbitals.

Denticity Inorganic & Coordination Chemistry Dimensionless The number of donor atoms a single ligand uses to bind to one metal centre. κⁿ or ηⁿ notation

d–d Transition Inorganic & Coordination Chemistry nm The promotion of an electron between split d orbitals, responsible for the characteristic colours of transition metal complexes. ΔE = hν = Δ

Effective Atomic Number Rule Inorganic & Coordination Chemistry Dimensionless The observation that stable metal carbonyls tend to have a total electron count equal to that of the next noble gas. EAN = Z − oxidation state + 2n(ligands)

Ellingham Diagram Inorganic & Coordination Chemistry kJ/mol A plot of the standard free energy of formation of metal oxides against temperature, used to choose a reduction route. ΔG° = ΔH° − TΔS°

Flux Inorganic & Coordination Chemistry Dimensionless A substance added during smelting to combine with the gangue and form a fusible slag.

Froth Flotation Inorganic & Coordination Chemistry Dimensionless A concentration method that separates minerals by exploiting differences in how readily their surfaces are wetted.

Gangue Inorganic & Coordination Chemistry Dimensionless The commercially worthless rock and mineral matter surrounding a valuable ore mineral.

Geometrical Isomerism in Complexes Inorganic & Coordination Chemistry Dimensionless Stereoisomerism arising from different spatial arrangements of ligands around the metal centre. cis / trans, fac / mer

High Spin Complex Inorganic & Coordination Chemistry BM A complex in which electrons occupy the higher d orbitals singly before pairing, maximising unpaired spins. Δ < P