9.15 Specify the oxidation numbers of the metals in the following coordination entities: (i) [Co(H2O)(CN)(en)2] 2+ (ii) [CoBr2(en)2] + (iii) [PtCl4] 2– (iv) K3[Fe(CN)6] (v) [Cr(NH3)3Cl3]

(i) Let Oxidation of Co be x and charge on the complex is given as + 2 H2O has Oxidation Number: 0 CN has Oxidation Number: -1 en has Oxidation Number :0 (ii) Let Oxidation number of Co be x and charge on the complex is given as + 1 Br has Oxidation number: 1 en has oxidation number : 0 (iii) Let Oxidation number of Pt be x and charge on the complex is given as -2 Cl has oxidation number : -1 (iv) This complex can also be seen as [Fe (CN)6]3- Let Oxidation number of Fe be x and charge given on the complex is given as -3 CN has oxidation number : -1 (v) Let Oxidation number of Cr be x and charge given on the complex is given as 0 NH3 has oxidation number : 0 Cl has oxidation number: -1

9.8 Explain [Co(NH3 )6 ] 3+ is an inner orbital complex whereas [Ni(NH3 )6 ] 2+ is an outer orbital complex.

[Co (NH3)6]3+ [Ni (NH3)6]2+ Oxidation state of cobalt: Overall charge balance: X + 6 (0) = 3 X = + 3 Oxidation state of nickel: Overall charge balance: X + 6 (0) = 2 X = + 2 Outer electronic configuration of cobalt = d6 Outer electronic configuration of nickel = d8 NH3 is a strong field ligand so it causes pairing of electron. Therefore cobalt undergoes d2sp3 hybridisation. As in the hybridisation d2 orbitals are used from the (n-1)d orbitals (inner orbitals as n = 4 being quantum number) . hence it is a inner orbital complex. NH3 is a strong field ligand so it causes pairing of electron. Therefore, nickel undergoes sp3 d2 hybridisation. As in the hybridisation, d2 orbitals are used from the and orbitals (outer orbitals as n = 4 being quantum number). Hence, it is an outer orbital complex

9.6 [NiCl4 ] 2– is paramagnetic while [Ni(CO)4 ] is diamagnetic though both are tetrahedral. Why?

In [Ni (Cl)4]2- ion, Cl- is a weak field ligand so it will not pair the unpaired electrons of Ni+2 ion. Electronic configuration of Ni is: [Ar]3d84s2 where [Ar] = 1s22s22p63s23p6 Electronic configuration of Ni+2 = [Ar]3d8 Outer electronic configuration of Ni+2 = 3d8 Overall charge balance: X + 4 (-1) = -2 X = + 2. Therefore it undergoes sp3 hybridization. So it will have tetrahedral geometry. Since there are 2 unpaired electrons in the d orbital so it is a paramagnetic compound. In [Ni (Co)4]: Overall charge is neutral and oxidation state of Ni can be calculated as: X + 4 (0) = 0 x = 0 Ni is in zero oxidation state. Co is a strong field ligand it causes pairing of the 4 unpaired electrons in d orbital. Also, it causes the 4s electrons to shift to the 3d orbital, thereby undergoes sp3 hybridisation forming tetrahedral geometry. Since it has no unpaired electron, therefore it is diamagnetic compound.

NCERT Solutions for Class 12 Chemistry Chapter 5 Coordination Compounds

Q: 9.5 Explain on the basis of valence bond theory that [Ni(CN)4 ] 2– ion with square planar structure is diamagnetic and the [NiCl4 ] 2– ion with tetrahedral geometry is paramagnetic.

According to the valence band theory, the central metal atom or ion under the influence of ligands can use its (n-1)d, ns, np (inner orbital complex) or ns, np, and (outer orbital complex)orbitals for hybridisation to form equivalent set of orbitals of definite geometry. In [Ni (CN)4]2-, oxidation state of Ni can be calculated as : Using overall charge balance as the whole ion has overall -2 charge: x + 4 (-1) = -2 (? CN- has -1 negative charge) x = + 2 Ni is in + 2 oxidation state. Electronic configuration of Ni is: [Ar]3d84s2 Where, [Ar] = 1s22s22p63s23p6 Electronic configuration of Ni+2 = [Ar]3d8 Outer electronic configuration of Ni+2 = 3d8 Since there are 4 CN ions so they can either form tetrahedral or square planar geometry. And CN- is a strong field ligand (according to experimental data of spectro-chemical series) it causes pairing of the 2 unpaired electrons. It undergoes dsp2 (one d orbital, one s and two p orbitals used by the ligands) hybridization and forms square planar structure. Since all the electrons are paired so it is diamagnetic. Paramagnetic compounds- those compounds which have one or more no. of unpaired electrons in their atomic orbitals. Diamagnetic compounds-those compounds in which all the electrons in their atomic orbitals are paired. Co-ordination number Type of hybridisation Distribution of hybrid orbitals in space 4 sp3 Tetrahedral 4 dsp3 Square planar 5 sp3d Trigonalbipyramidal 6 sp3d2 Octahedral 6 d2sp3 octahedral In case of [Ni (Cl)4]2- ion, Cl- is a weak field ligand so it will not pair the unpaired electrons of Ni+2 ion. Therefore it undergoes sp3 hybridization. Overall charge balance: X + 4 (-1) = -2 X = + 2. Since there are 2 unpaired electrons in the d orbital so it is a paramagnetic compound.

Q: 9.3 Indicate the types of isomerism exhibited by the following complexes and draw the structures for these isomers: (i) K[Cr(H2O)2 (C2O4 )2 (ii) [Co(en)3 ]Cl3 (iii) [Co(NH3 )5 (NO2 )](NO3 )2 (iv) [Pt(NH3 )(H2O)Cl2 ]

(i) K [Cr (H2O)2 (C2O4)2 exhibits geometrical isomerism (Cis and trans) and optical isomerism of cis and trans (ii) Optical isomerism exhibiting mirror (iii) Ionisation isomerism- [Co (NH3)5 (NO3)] (NO3) (NO2) and Linkage isomerism- [Co (NH3)5 (ONO)] (NO3)2 (iv) Geometrical isomers are seen in [Pt (NH3) (H2O)Cl2]

Updated on Jul 16, 2025 16:45 IST

By Pallavi Pathak, Assistant Manager Content

Coordination Chemistry Class 12 talks about the Coordination Compounds, which is an important and challenging area of modern inorganic chemistry. A variety of industrial catalysts, metallurgical processes, and analytical reagents use coordination compounds. It also finds applications in textile dyeing, electroplating, and medicinal chemistry.
Coordination Compounds NCERT Solutions help students to understand the key concepts of the chapter, which include - Werner's theory of coordination compounds, meaning of terms such as central atom/ion, coordination entity, coordination number, ligand, coordination polyhedron, coordination sphere, homoleptic, oxidation number and heteroleptic. It also covers the rules, formulas, and names of the coordination compounds.

Quick Summary of Coordination Compounds NCERT

Here is a walkthrough of the Class 12 Coordination Compounds NCERT Solutions:

The recent advances in coordination compounds have provided the development of new concepts, molecular structure, models of bonding, vital insights and novel breakthroughs.
The Valence Bond Theory (VBT) explains the creation, magnetic behavior, and geometrical shapes of coordination compounds.
The Crystal Field Theory (CFT) is dependent on the effect of different crystal fields and the d orbital energies of the central metal atom/ion's degeneracy.
Coordination Compounds is an important chapter. It provides insight into the functioning and structures of vital components of biological systems. Moreover, it has applications in analytical and medicinal chemistry and metallurgical processes.

Topics Covered in NCERT Chemistry Class 12 Coordination Compounds Chapter

NCERT Solutions Coordination Compounds offer deep insights into how metals and ligands interact with each other to form complex structures. The chapter helps students to understand molecular bonding, geometry, and isomerism, which are important for studies in higher education in medicine, pharmacy, chemistry, and materials science.

See the table below for the topics covered in the Coordination Compounds:

Exercise	Topics Covered
5.1	Werner's Theory of Coordination Compounds
5.2	Definitions of Some Important Terms Pertaining to Coordination Compounds
5.3	Nomenclature of Coordination Compounds
5.4	Isomerism in Coordination Compounds
5.5	Bonding in Coordination Compounds
5.6	Bonding in Metal Carbonyls
5.7	Importance and Applications of Coordination Compounds

Class 12 Chemistry Chapter 5 Coordination Compounds Weightage in NEET, JEE Main Exam

Exam	Number of Questions	Weightage
NEET	2-3 questions	3-6%
JEE Main	2-3 questions	3-10%

Try these practice questions

Q1:

Correct statement about photo –chemical smog is:

It occurs in humid climate.

It is a mixture of smoke, fog and SO₂

It is reducing of smog.

It result from reaction of unsaturated hydrocarbons

Q2:

Given below are two statements:

Statement I : ${[N i {(C N)}_{4}]}^{2 -}$ is square planar and diamagnetic complex, with dsp² hybridizatin for Ni but $[N i {(C O)}_{4}]$ is tetrahedral, paramagnetic and with sp³ hybridization for Ni.

Statement II : ${[N i C l_{4}]}^{2 -} a n d [N i {(C O)}_{4}]$ both hav

View Full Question

Both Statement I and Statement II are true.

Both Statement I and Statement II are false.

Statement I is correct but Statement II is false.

Statement I is incorrect but Statement II is true.

Important Formulas of Class 12 Chemistry Coordination Compounds

Class 12 Coordination Compounds: Important Formulae and Applications

Concept	Formula
Magnetic Moment	$\mu = \sqrt{n(n+2)}$
Crystal Field Splitting	$\Delta_t = \frac{4}{9} \Delta_o$
Oxidation State	$\sum (Charge of Ligands) + x = Overall Charge$

Class 12 Coordination Compounds NCERT Solution PDF: Download PDF For Free

Students can download the Coordination Compounds NCERT PDF from the link given below. The well-structured NCERT solutions are easy to understand. It is prepared by the subject matter experts to improve students' problem-solving skills. It can help students in exam preparation and scoring high in the CBSE Board exam and competitive exams like NEET and JEE Main.

Download Here: NCERT Solution for Class XII Chemistry Coordination Compounds PDF

Class 12 Chemistry Coordination Compounds Solutions for Intex Questions

Students can find here the NCERT Solutions for Coordination Compounds Intext questions below. Verify your answers and know how well you have understood the topics.

Q 9.1 Write the formulas for the following coordination compounds:

(i) Tetraamminediaquacobalt(III) chloride

(ii) Potassium tetracyanidonickelate(II)

(iii) Tris(ethane–1,2–diamine) chromium(III) chloride

(iv) Amminebromidochloridonitrito-N-platinate(II)

(v) Dichloridobis(ethane–1,2–diamine)platinum(IV) nitrate

(vi) Iron(III) hexacyanidoferrate(II)

Ans (i) [Co(NH₃)₄(H₂O)₂]Cl₃

(ii) K₂[Ni(CN)₄]

(iii) [Pt(en)₃]NO₃

(iv) [Pt(NH₃)BrCl(NO₂)]

(v) [Pt(Cl)₂(en)₂](NO₃)₂

(vi) Fe₄[Fe(CN)₆]₃

Q 9.2 Write the IUPAC names of the following coordination compounds:

(i) [Co(NH₃ )₆ ]Cl₃

(ii) [Co(NH₃ )₅Cl]Cl₂

(iii) K₃ [Fe(CN)₆ ]

(iv) K₃ [Fe(C₂O₄ )₃ ]

(v) K₂ [PdCl₄ ]

(vi) [Pt(NH₃ )₂Cl(NH₂CH₃ )]

Ans (i) Hexaminecobalt(III)chloride

(ii) Pentaaminechloridecobalt(III)chloride

(iii) Potassium hexacyanoferrate(III)

(iv) Potassium trioxalatoferrate(III)

(v) Potassium tetrachloridopalladate(II)

(vi) Diaminechloride(methylamine)platinum(II)chloride

Q 9.3 Indicate the types of isomerism exhibited by the following complexes and draw the structures for these isomers:

(i) K[Cr(H₂O)₂ (C₂O₄ )₂

(ii) [Co(en)₃ ]Cl₃

(iii) [Co(NH₃ )₅ (NO₂ )](NO₃ )₂

(iv) [Pt(NH₃ )(H₂O)Cl₂ ]

Ans (i) K[Cr(H₂O)₂(C₂O₄)₂ exhibits geometrical isomerism (Cis and trans) and optical isomerism of cis and trans

(ii) Optical isomerism exhibiting mirror

(iii) Ionisation isomerism- [Co(NH₃)₅(NO₃)](NO₃)(NO₂) and Linkage isomerism-[Co(NH₃)₅(ONO)](NO₃)₂

(iv) Geometrical isomers are seen in [Pt(NH₃)(H₂O)Cl₂]

Q 9.4 Give evidence that [Co(NH₃ )₅Cl]SO₄ and [Co(NH₃ )₅ (SO₄ )]Cl are ionisation isomers.

Ans These compounds give different ions in aqueous solution. This can be tested by using AgNO₃ solution and BaCl₂

[Co(NH₃)₅Cl]SO_4(aq) + BaCl_2(aq) → BaSO_4(ppt)

[Co(NH₃)₅Cl]SO_4(aq) + AgNO_3(aq) → no reaction

[Co(NH₃)₅(SO₄)]Cl_(aq) + BaCl_2(aq) → no reaction

[Co(NH₃)₅(SO₄)]Cl_(aq) + AgNO_3(aq) → AgCl_(ppt)

Hence, they give different precipitates with different solutions. Thus, they are ionisation isomers.

Commonly asked questions

9.5 Explain on the basis of valence bond theory that [Ni(CN)₄ ] ^2– ion with square planar structure is diamagnetic and the [NiCl₄ ] ^2– ion with tetrahedral geometry is paramagnetic.

9.15 Specify the oxidation numbers of the metals in the following coordination entities:

(i) [Co(H₂O)(CN)(en)₂] ²⁺
(ii) [CoBr₂(en)₂] ⁺
(iii) [PtCl₄] ^2–
(iv) K₃[Fe(CN)₆]
(v) [Cr(NH₃)₃Cl₃]

9.8 Explain [Co(NH₃ )₆ ] ³⁺ is an inner orbital complex whereas [Ni(NH₃ )₆ ] ²⁺ is an outer orbital complex.

9.6 [NiCl₄ ]^2– is paramagnetic while [Ni(CO)₄ ] is diamagnetic though both are tetrahedral. Why?

9.3 Indicate the types of isomerism exhibited by the following complexes and draw the structures for these isomers:

(i) K[Cr(H₂O)₂ (C₂O₄ )₂

(ii) [Co(en)₃ ]Cl₃

(iii) [Co(NH₃ )₅ (NO₂ )](NO₃ )₂

(iv) [Pt(NH₃ )(H₂O)Cl₂ ]

9.12 FeSO₄ solution mixed with (NH₄)₂SO₄ solution in 1:1 molar ratio gives the test of Fe²⁺ ion but CuSO₄ solution mixed with aqueous ammonia in 1:4 molar ratio does not give the test of Cu²⁺ ion. Explain why?

9.16 Using IUPAC norms write the formulas for the following:

(i) Tetrahydroxidozincate(II)

(ii) Potassium tetrachloridopalladate(II)

(iii) Diamminedichloridoplatinum(II)

(iv) Potassium tetracyanidonickelate(II)

(v) Pentaamminenitrito-O-cobalt(III)

(vi) Hexaamminecobalt(III) sulphate

(vii) Potassium tri(oxalato)chromate(III)

(viii) Hexaammineplatinum(IV)

(ix) Tetrabromidocuprate(II)

(x) Pentaamminenitrito-N-cobalt(III)

9.9 Predict the number of unpaired electrons in the square planar [Pt(CN)₄ ] ^2– ion.

9.10 The hexaquomanganese(II) ion contains five unpaired electrons, while the hexacyanoion contains only one unpaired electron. Explain using Crystal Field Theory.

9.13 Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.

9.7 [Fe(H2O)₆ ] ³⁺ is strongly paramagnetic whereas [Fe(CN)₆ ] ^3– is weakly paramagnetic. Explain.

9.20 Draw the structures of optical isomers of: (i) [Cr(C2O4)3] 3– (ii) [PtCl2(en)2] 2+ (iii) [Cr(NH3)2Cl2(en)]+

9.28 What is crystal field splitting energy? How does the magnitude of ?o decide the actual configuration of d orbitals in a coordination entity?

9.17 Using IUPAC norms write the systematic names of the following:

(i) [Co(NH3)6]Cl3

(ii) [Pt(NH3)2Cl(NH2CH3)]Cl

(iii) [Ti(H2O)6] 3+

(iv) [Co(NH3)4Cl(NO2)]Cl

(v) [Mn(H2O)6] 2+

(vi) [NiCl4] 2–

(vii) [Ni(NH3)6]Cl2

(viii) [Co(en)3] 3+

(ix) [Ni(CO)4]

9.2 Write the IUPAC names of the following coordination compounds:

(i) [Co(NH₃ )₆ ]Cl₃

(ii) [Co(NH₃ )₅Cl]Cl₂

(iii) K₃ [Fe(CN)₆ ]

(iv) K₃ [Fe(C₂O₄ )₃ ]

(v) K₂ [PdCl₄ ]

(vi) [Pt(NH₃ )₂Cl(NH₂CH₃ )]

9.18 List various types of isomerism possible for coordination compounds, giving an example of each.

9.19 How many geometrical isomers are possible in the following coordination entities? (i) [Cr(C2O₄)₃] ^3– (ii) [Co(NH₃)₃Cl₃]

9.34 Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex:

9.33 Give the oxidation state, d orbital occupation and coordination number of the central metal ion in the following complexes:

(i) K₃[Co(C₂O₄)₃]

(ii) cis-[CrCl₂(en)₂]Cl

(iii) (NH₄)₂[CoF₄]

(iv) [Mn(H₂O)₆]SO₄

9.21 Draw all the isomers (geometrical and optical) of:

(i) [CoCl₂(en)₂] ⁺

(ii) [Co(NH₃)Cl(en)2]²⁺

(iii) [Co(NH₃)2Cl₂(en)]⁺

9.23 Aqueous copper sulphate solution (blue in colour) gives: (i) a green precipitate with aqueous potassium fluoride and (ii) a bright green solution with aqueous potassium chloride. Explain these experimental results.

9.11 Explain the bonding in coordination compounds in terms of Werner’s postulates.

9.4 Give evidence that [Co(NH₃ )₅Cl]SO₄ and [Co(NH₃ )₅ (SO₄ )]Cl are ionisation isomers.

9.14 What is meant by unidentate, didentate and ambidentate ligands? Give two examples for each.

9.22 Write all the geometrical isomers of [Pt(NH₃)(Br)(Cl)(py)] and how many of these optical isomers?

9.24 What is the coordination entity formed when excess of aqueous KCN is added to an aqueous solution of copper sulphate? Why is it that no precipitate of copper sulphide is obtained when H₂S(g) is passed through this solution?

9.25 Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory:

(i) [Fe(CN)₆] ^4–

(ii) [FeF₆] ^3–

(iii) [Co(C₂O₄)₃] ^3–

(iv) [CoF₆] ^3–

9.26 Draw figure to show the splitting of d orbitals in an octahedral crystal field.

9.29 [Cr(NH₃)₆] ³⁺ is paramagnetic while [Ni(CN)₄]^2– is diamagnetic. Explain why?

9.1 Write the formulas for the following coordination compounds:

(i) Tetraamminediaquacobalt(III) chloride

(ii) Potassium tetracyanidonickelate(II)

(iii) Tris(ethane–1,2–diamine) chromium(III) chloride

(iv) Amminebromidochloridonitrito-N-platinate(II)

(v) Dichloridobis(ethane–1,2–diamine)platinum(IV) nitrate

(vi) Iron(III) hexacyanidoferrate(II)

9.27 What is spectrochemical series? Explain the difference between a weak field ligand and a strong field ligand.

9.30 A solution of [Ni(H2O)₆] ²⁺ is green but a solution of [Ni(CN)₄] ^2– is colourless. Explain.

9.31 [Fe(CN)₆] ^4– and [Fe(H2O)₆] ²⁺ are of different colours in dilute solutions. Why?

9.32 Discuss the nature of bonding in metal carbonyls.

Benefit of using NCERT Solutions for Class 12 Chemistry Chapter 5

Class 12 Coordination Compounds NCERT solutions benefits are as follows:

Enhance the conceptual knowledge

Improve problem solving skills

Good for revision and practice

Boost confidence in the students

NCERT Chemistry Chapter 5 Coordination Compounds – FAQs

Students can check Coordination Compounds ncert solution pdf faqs below.

Explore exams which ask questions on Chemistry Ncert Solutions Class 12th

Select your preferred stream

Engineering

Medicine

Boards

View more exams

Chemistry Ncert Solutions Class 12th Exam

Student Forum

Anything you would want to ask experts?

Write here...

Other Similar chapters for you

News & Updates

Latest NewsPopular News

NCERT Class 12 Chemistry Notes for CBSE	NCERT Notes for Class 11 & 12
Class 12 Chemistry NCERT Solutions	NCERT Solutions Class 11 and 12 for Maths, Physics, Chemistry

NCERT Solutions for Class 12 Chemistry Chapter 5 Coordination Compounds

Related Links

Quick Summary of Coordination Compounds NCERT

Topics Covered in NCERT Chemistry Class 12 Coordination Compounds Chapter

Class 12 Chemistry Chapter 5 Coordination Compounds Weightage in NEET, JEE Main Exam

Try these practice questions

Important Formulas of Class 12 Chemistry Coordination Compounds

Class 12 Coordination Compounds: Important Formulae and Applications

Class 12 Coordination Compounds NCERT Solution PDF: Download PDF For Free

Class 12 Chemistry Coordination Compounds Solutions for Intex Questions

Commonly asked questions

Benefit of using NCERT Solutions for Class 12 Chemistry Chapter 5

NCERT Chemistry Chapter 5 Coordination Compounds – FAQs

Explore exams which ask questions on Chemistry Ncert Solutions Class 12th

Student Forum

Other Similar chapters for you

News & Updates

NEET PG Counselling 2025 Dates & Schedule Soon @mcc.nic.in Live Updates; Check Eligibility & Documents Required

AP 10th Exam Date 2026 Shortly @bse.ap.gov.in; Check Live Updates on AP SSC Time Table 2026

MAHA TET Registration 2025 Last Date (9 Oct) LIVE: Get Eligibility & Exam Dates @mahatet.in

Tamil Nadu 10th, 12th Public Time Table 2026 Soon @dge.tn.gov.in; Check Live Updates on TN SSLC, Plus Two Dates

UP Board Exam Date Sheet 2026 Class 10, 12 (Soon) Live Updates; Check UPMSP High School, Inter Time Table

JEE Main Marks vs Percentile vs Rank 2025: Calculate Percentile and Rank Using Marks

List of NIT Colleges in India 2025 - NIRF Ranking, Courses, Seats, Cutoff, Fees and Placement

CBSE 10th Maths Question Paper 2025, 2024, 2023, 2022, 2020, 2019 PDF Download

NEET Chapter Wise Weightage 2026 PDF by NTA: Physics, Chemistry & Biology

List of Top IITs in India 2025: NIRF Ranking, Courses, Seats, Fees & Placement