Order: cation first, anion second; ligands in alphabetical order before metal; use Greek prefixes (di, tri, tetra...) for ligand multiplicity; oxidation state in parentheses. Example: [Co(NH₃)₆]Cl₃ = hexaamminecobalt(III) chloride.
-- NCERT Class 12 Chemistry, Ch. 5, p. 123IUPAC Nomenclature Coordination
8 MCQs9-step worked example
Source: NCERT Coordination CompoundsPYQ coverage: NEET 2022, 2026Official key: NTA-verifiedLast updated: 24 Sep 2026
IUPAC Nomenclature Coordination, explained for NEET
The naming trap in IUPAC nomenclature of coordination compounds is deceptively simple: you know the rules individually, but under exam pressure you scramble the order of ligands, botch a multiplicity prefix, or misassign the oxidation state. NEET exploits this — a wrong alphabetical sequence or a missing Roman numeral costs you 5 marks (−1 for the wrong pick plus +4 lost).
The IUPAC naming protocol (NCERT Class 12 Chemistry Chapter 5, page 125) follows a strict sequence:
- Cation first, anion second — regardless of which is the complex ion.
- Ligands before metal — within the coordination sphere, list ligands alphabetically by their IUPAC ligand name (not by the prefix).
- Multiplicity prefixes — di-, tri-, tetra- for simple ligands; bis-, tris-, tetrakis- for ligands whose names already contain a prefix or are polydentate (e.g., bis(ethylenediamine), not diethylenediamine).
- Anionic ligands end in -o — chlorido (Cl⁻), cyanido (CN⁻), hydroxido (OH⁻). Neutral ligands keep their name, except aqua (H₂O), ammine (NH₃), carbonyl (CO), nitrosyl (NO).
- Metal name — in a cationic or neutral complex, use the English name; in an anionic complex, use the Latin-root name with the suffix -ate (ferrate, cuprate, argentate).
- Oxidation state — Roman numeral in parentheses immediately after the metal name. No space.
Watch-out: Alphabetical order uses the ligand name stripped of its prefix. Ammine comes before chlorido because "a" < "c" — even if you write "dichlorido" and "tetraammine," the alphabetical comparison is ammine vs chlorido, not tetra vs di.
For anionic complexes, forgetting the -ate suffix or using the English metal name instead of the Latin root is a common confusion in NEET options.
Can you answer these IUPAC Nomenclature Coordination MCQs?
Select an option to see the explanation. Wrong answers show why your choice was tempting — and name the exact trap it exploits.
MCQ 1Easy RecallPractice
In the IUPAC name of a coordination compound, ligands are listed in which order?
Show answer and why every option is right or wrong
Answer: C. IUPAC rules specify that ligands are listed in alphabetical order of their names (ignoring multiplicity prefixes). This is stated in NCERT Class 12 Chemistry Chapter 5, page 125.
Why A is wrong: A is wrong because IUPAC naming no longer groups ligands by charge class; alphabetical order is the current convention.
Why B is wrong: B is wrong because ligand size plays no role in the naming sequence; the order is purely alphabetical by name.
Why D is wrong: D is wrong because electronegativity of the donor atom does not determine the listing order of ligands in the name.
MCQ 2Easy RecallPractice
When a coordination compound is anionic, the metal in the name receives which treatment?
Show answer and why every option is right or wrong
Answer: A. In anionic coordination entities, IUPAC rules require the Latin-root name of the metal followed by -ate (e.g., ferrate for iron, cuprate for copper). NCERT Class 12 Chemistry Chapter 5, page 125.
Why B is wrong: B is wrong because the English name without a suffix is used only for cationic or neutral complexes, not anionic ones.
Why C is wrong: C is wrong because in all coordination compound names, ligands are listed before the metal — this does not change for anionic complexes.
Why D is wrong: D is wrong because the oxidation state in Roman numerals is always included regardless of the charge on the complex ion.
MCQ 3Easy RecallPractice
Which of the following ligands is named "ammine" (with double m) in IUPAC nomenclature?
Show answer and why every option is right or wrong
Answer: D. NH₃ as a ligand is called ammine (double m). This is a special IUPAC ligand name distinct from "amine" (organic functional group). NCERT Class 12 Chemistry Chapter 5, page 125.
Why A is wrong: A is wrong because NO as a ligand is called nitrosyl, not ammine.
Why B is wrong: B is wrong because CO as a ligand is called carbonyl.
Why C is wrong: C is wrong because H₂O as a ligand is called aqua.
MCQ 4Direct ApplicationPractice
The IUPAC name of [Co(NH₃)₄Cl₂]Cl is:
Show answer and why every option is right or wrong
Answer: A. Ligands alphabetically: ammine (a) before chlorido (c). Prefixes: tetraammine, dichlorido. Cobalt oxidation state: +3 (total charge of complex ion is +1, two Cl⁻ inside contribute −2, four NH₃ are neutral → Co = +3). Counter ion: chloride. NCERT Class 12 Chemistry Chapter 5, page 125.
Why B is wrong: B is wrong because it places dichlorido before tetraammine. Alphabetical order is determined by the ligand name (ammine vs chlorido), not the prefix. Since a < c, ammine comes first.
Why C is wrong: C is wrong because the oxidation state is miscalculated as +2. The complex ion [Co(NH₃)₄Cl₂]⁺ has overall charge +1; with 2 Cl⁻ (−2) and 4 neutral NH₃, cobalt must be +3.
Why D is wrong: D is wrong because there is only one chloride counter ion (the compound is [Co(NH₃)₄Cl₂]Cl, not [Co(NH₃)₄Cl₂]Cl₂), and 'dichloride' for the counter ion is incorrect.
MCQ 5Direct ApplicationPractice
What is the IUPAC name of K₃[Fe(CN)₆]?
Show answer and why every option is right or wrong
Answer: B. The complex ion [Fe(CN)₆]³⁻ is anionic, so iron takes its Latin-root name with -ate suffix → ferrate. Six CN⁻ contribute −6 charge; overall complex charge is −3; so Fe = +3. Counter cation: potassium. NCERT Class 12 Chemistry Chapter 5, page 125.
Why A is wrong: A is wrong because in an anionic complex, the metal must use the Latin-root name with -ate (ferrate), not the English name (iron).
Why C is wrong: C is wrong because the oxidation state of iron is +3, not +2. The complex ion has charge −3 and six CN⁻ contribute −6, so Fe = −3 − (−6) = +3.
Why D is wrong: D is wrong because IUPAC rules do not attach a multiplicity prefix to the counter cation in the name. It is simply 'potassium,' not 'tripotassium.'
MCQ 6Direct ApplicationPractice
The complex [Cr(en)₂Cl₂]⁺ contains the bidentate ligand ethylenediamine (en). The correct multiplicity prefix for two en ligands in the IUPAC name is:
Show answer and why every option is right or wrong
Answer: B. Ethylenediamine already contains the prefix "di" in its name (and is polydentate), so the multiplicative prefix bis- is used instead of di- to avoid ambiguity: bis(ethylenediamine). NCERT Class 12 Chemistry Chapter 5, page 125.
Why A is wrong: A is wrong because di- is reserved for simple ligands whose names do not already contain a prefix. Since ethylenediamine contains 'di,' using di(ethylenediamine) creates ambiguity.
Why C is wrong: C is wrong because tetra- would indicate four ligands, not two. There are only two ethylenediamine ligands in this complex.
Why D is wrong: D is wrong because with two identical ligands, a multiplicity prefix is mandatory to indicate the count.
MCQ 7Concept TrapPractice
A student writes the IUPAC name of [Pt(NH₃)₂Cl(NO₂)] as "diamminechloridonitroplatinum(II)." Assuming the ligand is NO₂⁻ bonded through nitrogen, which part of the name is incorrect?
Show answer and why every option is right or wrong
Answer: B. When NO₂⁻ coordinates through nitrogen, NCERT names it nitrito-N (IUPAC 2005 writes nitrito-κN), and O-bonded NO₂⁻ is nitrito-O; nitro is the older name. NCERT's own worked example names this exact complex diamminechloridonitrito-N-platinum(II). NCERT Class 12 Chemistry Chapter 5, page 125 discusses ambidentate ligands.
Why A is wrong: A is wrong because ammine is a simple ligand name (it does not inherently contain a multiplicity prefix), so 'diammine' is the correct form, not 'bis(ammine).'
Why C is wrong: C is wrong because Pt oxidation state is +2: one Cl⁻ and one NO₂⁻ contribute −2 total anionic charge inside the neutral complex with two neutral NH₃ ligands, giving Pt = +2.
Why D is wrong: D is wrong because alphabetical order compares 'ammine' (a) with 'chlorido' (c); since a < c, ammine correctly precedes chlorido.
MCQ 8Concept TrapPractice
Two coordination compounds have the formulas [Co(NH₃)₅Br]SO₄ and [Co(NH₃)₅SO₄]Br. In their IUPAC names, which of the following correctly distinguishes them?
Show answer and why every option is right or wrong
Answer: A. In the first compound, Br⁻ is inside the coordination sphere (ligand: bromido) and SO₄²⁻ is the counter ion (sulfate). In the second, SO₄²⁻ is the ligand (sulfato) and Br⁻ is the counter ion (bromide). This is an ionisation isomerism pair, and IUPAC nomenclature distinguishes them by which species is named as a ligand vs a counter ion. NCERT Class 12 Chemistry Chapter 5, page 125.
Why B is wrong: B is wrong because although both compounds share the same molecular formula, they are ionisation isomers with different coordination spheres, and IUPAC rules produce distinct names for each.
Why C is wrong: C is wrong because in both compounds the complex ion is cationic (cobalt is the central atom of the cation), so the -ate suffix does not apply to either.
Why D is wrong: D is wrong because both compounds have five NH₃ ligands in the coordination sphere; the prefix 'pentaammine' is identical in both names.
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How do you solve a IUPAC Nomenclature Coordination question? A worked example
Pattern: IUPAC coordination compound naming (pattern P.CHE.U12.IUPAC_COORDINATION_NAMING, observed NEET 2022).
- 1
Given
• Formula: [CrCl₂(en)₂]Cl• en = ethylenediamine (bidentate, neutral ligand)• Complex ion: [CrCl₂(en)₂]⁺ (cationic, since Cl⁻ is counter ion)
- 2
Required
IUPAC name of the compound.
- 3
Concept
IUPAC naming rules for coordination compounds: cation named first, ligands alphabetically before metal, correct prefixes, oxidation state in Roman numerals, -ate suffix only for anionic complexes.
- 4
Identify components
• Ligands in coordination sphere: 2 Cl⁻ (anionic → chlorido) and 2 en (neutral, polydentate → ethylenediamine)• Counter ion: Cl⁻ (named as chloride)• Central metal: Cr
- 5
Apply naming rules
Alphabetical order of ligands: Compare "chlorido" (c) with "ethylenediamine" (e). c < e, so chlorido comes first.
Multiplicity prefixes:• 2 × chlorido → dichlorido (simple ligand, use di-)• 2 × ethylenediamine → bis(ethylenediamine) (polydentate ligand whose name contains "di," so use bis- with parentheses)
Oxidation state of Cr: Complex ion charge = +1. Two Cl⁻ inside contribute −2. Two en are neutral. So Cr + (−2) + 0 = +1 → Cr = +3.
Metal name: Complex is cationic → use English name: chromium. - 6
Assemble the name
Cation: dichloridob is(ethylenediamine)chromium(III)
Counter ion: chloride
Full name: Dichloridobis(ethylenediamine)chromium(III) chloride - 7
Final answer
Dichloridobis(ethylenediamine)chromium(III) chloride
- 8
Common trap
The most frequent error is writing "diethylenediamine" instead of "bis(ethylenediamine)." Because the ligand name ethylenediamine contains the fragment "di," the prefix di- would create ambiguity (diethylenediamine could be misread as a single ligand named "diethylenediamine"). The bis- prefix with parentheses resolves this.
A second trap: placing ethylenediamine before chlorido because "en" might be mentally shortened to "e." But alphabetical order uses the full ligand name — chlorido (c) comes before ethylenediamine (e). - 9
Similar NEET-style question
Try naming [CoCl₂(en)₂]NO₃ — the logic is identical, but the counter ion changes to nitrate and the metal is cobalt(III).
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What to remember before solving IUPAC Nomenclature Coordination questions
More in Coordination Compounds: 2 exam traps and mistakes · 2 formulas · 2 question patterns from its other lessons.
IUPAC Nomenclature Coordination questions from past NEET papers
2 questions from NEET 2022, 2026. Answers verified against NTA official keys.
NEET 2026
The formula of tetraammineaquachloridocobalt(III) chloride is
1[Co(NH₃)₄Cl₂] × H₂O
2[Co(NH₃)₄]Cl₃ × H₂O
3[Co(NH₃)₄(H₂O)Cl]Cl
4[Co(NH₃)₄(H₂O)Cl]Cl₂
NTA Answer: Option 4(final)
NEET 2022
The IUPAC name of the complex- [Ag(H2O)2][Ag(CN)2] is:
1diaquasilver(I) dicyanidoargentate(I)
2dicyanidosilver(II) diaquaargentate(II)
3diaquasilver(II) dicyanidoargentate(II)
4dicyanidosilver(I) diaquaargentate(I)
NTA Answer: Option 1(final)
How does NEET ask about IUPAC Nomenclature Coordination?
Recurring question shapes from past papers. Each pattern shows why wrong options look tempting.
Apply IUPAC rules: ligands alphabetical, prefixes for multiplicity, oxidation state of metal.
RecallMedium
Common distractors
wrong order ligands
Uses non-alphabetical order
Sources
NCERT refs: Class 12 Chemistry Chapter 5, p.125
Page numbers are the ones printed in the current NCERT textbook (2023 rationalised edition), unless marked pre-2023. The books are free at ncert.nic.in.
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