Complexes in which a central metal ion is bound to ligands through coordinate bonds.
Practise Bonding & Molecular Structure All Bonding & Molecular Structure topics
A coordination compound consists of a central metal ion bonded to surrounding ligands through coordinate covalent bonds. The metal and its ligands form a complex ion or neutral species with a defined geometry, and the number and arrangement of ligands determine its properties. Coordination compounds show characteristic colours, magnetism and catalytic activity, which arise from the d electrons of the metal and the field produced by the ligands. Many biological molecules are coordination compounds, including haemoglobin, which binds iron, and vitamin B12, which contains cobalt. They are central to inorganic chemistry, analysis and industrial catalysis.
Key ideas: Naming steps: ligands in alphabetical order, then metal with oxidation state in Roman numerals, anionic complexes end in -ate. Example: K3[Fe(CN)6] is potassium hexacyanoferrate(III). Determine oxidation state from the overall charge and ligand charges. Precipitation with AgNO3 shows which chloride ions are outside the coordination sphere.
Common mistakes and connections: Common errors are adding up charges without accounting for neutral ligands, counting counter-ions inside the brackets, and naming ligands in the wrong order. Also, Werner's work showed that CoCl3 with six NH3 releases three chlorides while with five releases two. Links to ligands, coordination number, isomerism, crystal field theory and colour.
Ligands bond strongly to metal ions: formation constants of ammine complexes show how stable these coordination compounds are in solution. The interactive lesson shows this as a live animation or chart.
The complex [Cu(NH3)4]2+ is deep blue because of the copper centre and its four ammonia ligands.
Complexes in which a central metal ion is bound to ligands through coordinate bonds.
Coordination Compounds is a intermediate topic in Bonding & Molecular Structure. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Bonding & Molecular Structure first: Diamond Structure, Graphene, Fullerenes.
The next topics in Bonding & Molecular Structure are Ligands and Coordination Number.
Yes. The interactive lesson includes a self-check question on Coordination Compounds, and the Bonding & Molecular Structure quiz draws on every topic in this area.
Coordination Compounds is topic 88 of 104 in Bonding & Molecular Structure.