How to Name Coordination Compounds (IUPAC Rules, Step by Step)

Do it in this fixed order. Step 1: Name the cation (positive part) first, then the anion (negative part) second - just like NaCl is sodium chloride. Step 2: Inside a complex ion, name the ligands first in alphabetical order, then the central metal. Step 3: Put Greek prefixes (di, tri, tetra, penta, hexa) to show how many of each ligand. Step 4: Write the metal's oxidation state right after its name as a Roman numeral in round brackets, with no space, e.g. cobalt(III). This matters for NEET because at least one nomenclature question appears almost every year.

You alphabetise by the ligand's own name, ignoring the multiplying prefix. So in a complex with 4 ammine and 2 chlorido, you compare 'a' (ammine) with 'c' (chlorido). Ammine comes first: tetraamminedichlorido..., not dichlorido first. The prefixes di, tri, tetra are only counters - they are invisible when sorting A to Z. Trap: students wrongly sort by 'd' of di or 't' of tetra. Only the root ligand name decides the order.

Look at the charge of the whole complex ion (the part inside the square brackets). If that complex ion is NEGATIVE (an anion), the metal name ends in '-ate', e.g. ferrate, cuprate, argentate. If the complex ion is POSITIVE or NEUTRAL, the metal keeps its ordinary English name, e.g. silver, cobalt, iron. So in [Ag(H2O)2][Ag(CN)2], the cation [Ag(H2O)2]+ gives 'silver' but the anion [Ag(CN)2]- gives 'argentate'. Same metal, two different endings, decided only by charge.

Some metals use their Latin stem when they are in an anionic complex. Silver -> argentate (from Latin argentum), iron -> ferrate (ferrum), copper -> cuprate (cuprum), lead -> plumbate (plumbum), tin -> stannate (stannum), gold -> aurate (aurum). NCERT lists these. So the anion [Ag(CN)2]- is dicyanidoargentate(I), NOT dicyanidosilverate. NEET 2022 tested exactly this in [Ag(H2O)2][Ag(CN)2].

The whole complex ion charge = metal oxidation state + sum of ligand charges. Neutral ligands (NH3, H2O) add 0. Anionic ligands add their charge (Cl- = -1, CN- = -1, C2O4^2- = -2). Example: [Ag(CN)2]- has 2 CN- = -2. So metal + (-2) = -1, giving Ag = +1. Write it as argentate(I). Always solve this small equation - the Roman numeral is not guessed.

Treat it exactly like a normal salt: cation named first, then anion. Name each complex ion separately by the usual rules. The cation [Co(NH3)6]3+ = hexaamminecobalt(III), the anion [Cr(CN)6]3- = hexacyanidochromate(III). Full name: hexaamminecobalt(III) hexacyanidochromate(III). The metal in the anion gets '-ate'; the metal in the cation does not.

Yes. In the modern 2005 IUPAC rules used by NCERT and NEET, anionic ligands ending in '-ide' become '-ido': chloride -> chlorido, cyanide -> cyanido, oxide -> oxido. Neutral ligands mostly keep their name but have special ones: NH3 = ammine, H2O = aqua, CO = carbonyl, NO = nitrosyl. Learn these four neutral names by heart.

For simple ligands use di, tri, tetra, penta, hexa. But when the ligand name already contains di/tri (like ethylenediamine or oxalato), use bis, tris, tetrakis instead, and put the ligand name in brackets. Example: two ethylenediamine = bis(ethylenediamine); three oxalato = tris(oxalato).

The whole complex ion name is written as ONE continuous word (all ligands + metal joined together). The oxidation state Roman numeral sits in round brackets right after the metal with no space. A space is used only between the cation part and the anion part of the full name, like a normal salt.

Nomenclature is a high-yield, low-effort topic - usually one direct question per year, either naming a formula, writing a formula from a name, or reading a name to classify it (homoleptic vs heteroleptic). It is guaranteed marks if you memorise the ligand names, the Latin '-ate' metals, and the 4-step order.

The reverse skill: writing the formula from a given name. NEET tests both directions (ReNEET 2026 gave a name and asked for the formula). Practise going both ways so you never get stuck.