Bonding and Crystal field

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JEE Main 2025

The correct order of the wavelength maxima of the absorption band in the ultraviolet-visible region for the given complexes is

[C o (C N)_{6}]^{3 -} < [C o (N H_{3})_{6}]^{3 +} < [C o (N H_{3})_{5} (H_{2} O)]^{3 +} < [C o (N H_{3})_{5} (C l)]^{2 +}

(B)

[C o (N H_{3})_{5} (C l)]^{2 +} < [C o (N H_{3})_{5} (H_{2} O)]^{3 +} < [C o (N H_{3})_{6}]^{3 +} < [C o (C N)_{6}]^{3 -}

(C)

[C o (C N)_{6}]^{3 -} < [C o (N H_{3})_{5} (C l)]^{2 +} < [C o (N H_{3})_{5} (H_{2} O)]^{3 +} < [C o (N H_{3})_{6}]^{3 +}

(D)

[C o (N H_{3})_{6}]^{3 +} < [C o (C N)_{6}]^{3 -} < [C o (N H_{3})_{5} (C l)]^{2 +} < [C o (N H_{3})_{5} (H_{2} O)]^{3 +}

JEE Advanced 2025

LEVELJEE Main

The sum of the spin only magnetic moment values (in B.M.) of $[Mn(Br)_{6}]^{3 -}$ and $[Mn(CN)_{6}]^{3 -}$ is ______.

JEE Advanced 2021

LEVELJEE Main

The calculated spin only magnetic moments of $[Cr (NH_{3})_{6}]^{3 +}$ and $[CuF_{6}]^{3 -}$ in BM, respectively, are (Atomic numbers of Cr and Cu are 24 and 29, respectively)

Addition of excess aqueous ammonia to a pink coloured aqueous solution of MCl_2. 6H_2O (X) and NH_4Cl gives an octahedral complex Y in the presence of air. In aqueous solution, complex Y behaves as 1 : 3 electrolyte. The reaction of X with excess HCl at room temperature results in the formation of a blue coloured complex Z. The calculated spin only magnetic moment of X and Z is 3.87 B.M., whereas it is zero for complex Y. Among the following options, which statements is(are) correct ?

* Multiple Correct Options

(A)

The hybridization of the central metal ion in Y is

d^{2} s p^{3}

(B)

Z is tetrahedral complex

(C)

Addition of silver nitrate to Y gives only two equivalents of silver chloride

(D)

When X and Z are in equilibrium at

0^{\circ} C

, the colour of the solution is pink

JEE Advanced 2022

LEVELJEE Advanced

LIST-I contains metal species and LIST-II contains their properties. [Given : Atomic number of $Cr = 24$ , $Ru = 44$ , $Fe = 26$ ] Match each metal species in LIST-I with their properties in LIST-II.

List-I

(P)

[Cr (CN)_{6}]^{4 -}

(Q)

[RuCl_{6}]^{2 -}

(R)

[Cr (H_{2} O)_{6}]^{2 +}

(S)

[Fe (H_{2} O)_{6}]^{2 +}

List-II

(1)

t_{2 g}

orbitals contain 4 electrons

(2)

μ (spin-only) = 4.9 BM

(3)

low spin complex ion

(4)

metal ion in 4+ oxidation state

(5)

d^{4}

species

JEE Advanced 2016

LEVELJEE Main

Among $[Ni (CO)_{4}]$ , $[NiCl_{4}]^{2 -}$ , $[Co (NH_{3})_{4} Cl_{2}] Cl$ , $Na_{3} [CoF_{6}]$ , $Na_{2} O_{2}$ and $CsO_{2}$ , the total number of paramagnetic compounds is -

Match the electronic configurations in List-I with appropriate metal complex ions in List-II and choose the correct option. [Atomic Number: Fe = 26, Mn = 25, Co = 27]

List-I

(P)

t_{2 g}^{6} e_{g}^{0}

(Q)

t_{2 g}^{3} e_{g}^{2}

(R)

e^{2} t_{2}^{3}

(S)

t_{2 g}^{4} e_{g}^{2}

List-II

(1)

[F e (H_{2} O)_{6}]^{2 +}

(2)

[M n (H_{2} O)_{6}]^{2 +}

(3)

[C o (N H_{3})_{6}]^{3 +}

(4)

[F e C l_{4}]^{-}

(5)

[C o C l_{4}]^{2 -}

JEE Advanced 2020

LEVELJEE Advanced

Choose the correct statement(s) among the following :

* Multiple Correct Options

(A)

[F e C l_{4}]^{-}

has tetrahedral geometry.

(B)

[C o (e n) (N H_{3})_{2} C l_{2}]^{+}

has 2 geometrical isomers.

(C)

[F e C l_{4}]^{-}

has higher spin-only magnetic moment than

[C o (e n) (N H_{3})_{2} C l_{2}]^{+}

(D)

The cobalt ion in

[C o (e n) (N H_{3})_{2} C l_{2}]^{+}

has

s p^{3} d^{2}

hybridization.

JEE Advanced 2018

LEVELJEE Advanced

Match each set of hybrid orbitals from LIST-I with complex (es) given in LIST-II.

List-I

(P)

d s p^{2}

(Q)

s p^{3}

(R)

s p^{3} d^{2}

(S)

d^{2} s p^{3}

List-II

(1)

[F e F_{6}]^{4 -}

(2)

[T i (H_{2} O)_{3} C l_{3}]

(3)

[C r (N H_{3})_{6}]^{3 +}

(4)

[F e C l_{4}]^{2 -}

(5)

N i (C O)_{4}

(6)

[N i (C N)_{4}]^{2 -}

JEE Advanced 2014

LEVELJEE Advanced

Comprehension Passage

An aqueous solution of metal ion

M_{1}

reacts separately with reagents

Q

and

R

in excess to give tetrahedral and square planar complexes, respectively. An aqueous solution of another metal ion

M_{2}

always forms tetrahedral complexes with these reagents. Aqueous solution of

M_{2}

on reaction with reagent

S

gives white precipitate which dissolves in excess of

S

. The reactions are summarized in the scheme given below.

Question 1:

$M_{1}$ , $Q$ and $R$ , respectively are

(A)

Zn^{2 +}

KCN

and

HCl

(B)

Ni^{2 +}

HCl

and

KCN

(C)

Cd^{2 +}

KCN

and

HCl

(D)

Co^{2 +}

HCl

and

KCN

Question 2:

Reagent $S$ is

(A)

K_{4} [Fe(CN)_{6}]

(B)

Na_{2} HPO_{4}

(C)

K_{2} CrO_{4}

(D)

KOH

JEE Advanced 2020

LEVELJEE Advanced

In an experiment, $m$ grams of a compound $X$ (gas/liquid/solid) taken in a container is loaded in a balance as shown in figure I below. In the presence of a magnetic field, the pan with $X$ is either deflected upwards (figure II), or deflected downwards (figure III), depending on the compound $X$ . Identify the correct statement(s)

* Multiple Correct Options

(A)

X

H_{2} O (l)

, deflection of the pan is upwards.

(B)

X

K_{4} [Fe (CN)_{6}] (s)

, deflection of the pan is upwards.

(C)

X

O_{2} (g)

, deflection of the pan is downwards.

(D)

X

C_{6} H_{6} (l)

, deflection of the pan is downwards.

JEE Advanced 2018

LEVELJEE Advanced

Among the species given below, the total number of diamagnetic species is____. $H atom, NO_{2} monomer, O_{2}^{-} (superoxide), dimeric sulphur in vapour phase, Mn_{3} O_{4}, (NH_{4})_{2} [FeCl_{4}], (NH_{4})_{2} [NiCl_{4}], K_{2} MnO_{4}, K_{2} CrO_{4}$

JEE Advanced 2018

LEVELJEE Advanced

The correct statement(s) regarding the binary transition metal carbonyl compounds is (are) (Atomic numbers : Fe = 26, Ni = 28)

* Multiple Correct Options

(A)

Total number of valence shell electrons at metal centre in

Fe(CO)_{5}

Ni(CO)_{4}

16

(B)

These are predominantly low spin in nature

(C)

Metal - carbon bond strengthens when the oxidation state of the metal is lowered

(D)

The carbonyl

C-O

bond weakens when the oxidation state of the metal is increased

JEE Advanced 2016

LEVELJEE Advanced

The geometries of the ammonia complexes of $Ni^{2 +}$ , $Pt^{2 +}$ and $Zn^{2 +}$ , respectively , are :

(A)

octahedral, square planar and tetrahederal

(B)

square planar, octahederal and tetrahederal

(C)

tetrahederal, square planar and octahederal

(D)

octahederal , tetrahederal and square planar

JEE Advanced 2015

LEVELJEE Main

For the octahedral complexes of $Fe^{3 +}$ in $SCN^{-}$ (thiocyanato-S) and in $CN^{-}$ ligand environments, the difference between the spin only magnetic moments in Bohr magnetons (when approximated to the nearest integer) is [Atomic number of $Fe = 26$ ]

JEE Main 2014

LEVELJEE Advanced

A list of species having the formula $XZ_{4}$ is given below : $XeF_{4}$ , $SF_{4}$ , $SiF_{4}$ , $BF_{4}^{-}$ , $BrF_{4}^{-}$ , $[Cu (NH_{3})_{4}]^{2 +}$ , $[FeCl_{4}]^{2 -}$ , $[CoCl_{4}]^{2 -}$ and $[PtCl_{4}]^{2 -}$ . Defining shape on the basis of the location of X and Z atoms, the total number of species having a square planar shape is

JEE Advanced 2021

LEVELJEE Advanced

The pair(s) of complexes wherein both exhibit tetrahedral geometry is(are) (Note: py = pyridine Given: Atomic numbers of Fe, Co, Ni and Cu are 26, 27, 28 and 29, respectively)

* Multiple Correct Options

(A)

[F e C l_{4}]^{-}

and

[F e (C O)_{4}]^{2 -}

(B)

[C o (C O)_{4}]^{-}

and

[C o C l_{4}]^{2 -}

(C)

[N i (C O)_{4}]

and

[N i (C N)_{4}]^{2 -}

(D)

[C u (p y)_{4}]^{+}

and

[C u (C N)_{4}]^{3 -}

JEE Main 2020

LEVELJEE Main

Considering that $Δ_{0} > P$ , the magnetic moment (in BM) of $[R u (H_{2} O)_{6}]^{2 +}$ would be ......... .

JEE Main 2020

LEVELJEE Advanced

$[Pd(F)(Cl)(Br)(I)]^{2 -}$ has $n$ number of geometrical isomers. Then, the spin-only magnetic moment and crystal field stabilisation energy [CFSE] of $[Fe(CN)_{6}]^{n - 6}$ respectively, are [Note: Ignore the pairing energy]

(A)

1.73 BM

and

- 2.0 Δ_{o}

(B)

2.84 BM

and

- 1.6 Δ_{o}

(C)

0 BM

and

- 2.4 Δ_{o}

(D)

5.92 BM

and

0

JEE Main 2020

LEVELJEE Main

The pair in which both the species have the same magnetic moment (spin only) is

(A)

[M n (H_{2} O)_{6}]^{2 +}

and

[C r (H_{2} O)_{6}]^{2 +}

(B)

[C r (H_{2} O)_{6}]^{2 +}

and

[F e (H_{2} O)_{6}]^{2 +}

(C)

[C o (O H)_{4}]^{2 -}

and

[F e (N H_{3})_{6}]^{2 +}

(D)

[C r (H_{2} O)_{6}]^{2 +}

and

[C o C l_{4}]^{2 -}

JEE Main 2021

LEVELJEE Main

The overall stability constant of the complex ion $[C u (N H_{3})_{4}]^{2 +}$ is $2.1 \times 1 0^{13}$ . The overall dissociations constant is $y \times 1 0^{- 14}$ . Then, $y$ is ......... . (Nearest integer)

JEE Main 2020

LEVELJEE Main

The electronic spectrum of $[T i (H_{2} O)_{6}]^{3 +}$ shows a single broad peak with a maximum at $20, 300 cm^{- 1}$ . The crystal field stabilisation energy (CFSE) of the complex ion, in $kJ mol^{- 1}$ , is ( $1 kJ mol^{- 1} = 83.7 cm^{- 1}$ )

The calculated magnetic moments (spin only value) for species $[FeCl_{4}]^{2 -}$ , $[Co (C_{2} O_{4})_{3}]^{3 -}$ and $MnO_{4}^{2 -}$ respectively are

The correct order of magnetic moments (spin only values in BM) among the following is (At. no of Mn = 25, Fe = 26, Co = 27)

(A)

[M n C l_{4}]^{2 -} > [C o C l_{4}]^{2 -} > [F e (C N)_{6}]^{4 -}

(B)

[M n C l_{4}]^{2 -} > [F e (C N)_{6}]^{4 -} > [C o C l_{4}]^{2 -}

(C)

[F e (C N)_{6}]^{4 -} > [M n C l_{4}]^{2 -} > [C o C l_{4}]^{2 -}

(D)

[F e (C N)_{6}]^{4 -} > [C o C l_{4}]^{2 -} > [M n C l_{4}]^{2 -}

JEE Main 2019

LEVELJEE Main

The correct order of the spin only magnetic moment of metal ions in the following low spin complexes, $[V (C N)_{6}]^{4 -}$ , $[F e (C N)_{6}]^{4 -}$ , $[R u (N H_{3})_{6}]^{3 +}$ , and $[C r (N H_{3})_{6}]^{2 +}$ , is

(A)

C r^{2 +} > R u^{3 +} > F e^{2 +} > V^{2 +}

(B)

V^{2 +} > C r^{2 +} > R u^{3 +} > F e^{2 +}

(C)

V^{2 +} > R u^{3 +} > C r^{2 +} > F e^{2 +}

(D)

C r^{2 +} > V^{2 +} > R u^{3 +} > F e^{2 +}

The correct order of the wavelength maxima of the absorption band in the ultraviolet-visible region for the given complexes is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The sum of the spin only magnetic moment values (in B.M.) of [Mn(Br)6​]3− and [Mn(CN)6​]3− is ______.

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The calculated spin only magnetic moments of [Cr(NH3​)6​]3+ and [CuF6​]3− in BM, respectively, are (Atomic numbers of Cr and Cu are 24 and 29, respectively)

List-I

List-II

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Among [Ni(CO)4​], [NiCl4​]2−, [Co(NH3​)4​Cl2​]Cl, Na3​[CoF6​], Na2​O2​ and CsO2​, the total number of paramagnetic compounds is -

Match the electronic configurations in List-I with appropriate metal complex ions in List-II and choose the correct option. [Atomic Number: Fe = 26, Mn = 25, Co = 27]

List-I

List-II

Choose the correct statement(s) among the following :

Match each set of hybrid orbitals from LIST-I with complex (es) given in LIST-II.

List-I

List-II

Comprehension Passage

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } M1​, Q and R, respectively are

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Reagent S is

The correct statement(s) regarding the binary transition metal carbonyl compounds is (are) (Atomic numbers : Fe = 26, Ni = 28)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The geometries of the ammonia complexes of Ni2+, Pt2+ and Zn2+, respectively , are :

The pair(s) of complexes wherein both exhibit tetrahedral geometry is(are) (Note: py = pyridine Given: Atomic numbers of Fe, Co, Ni and Cu are 26, 27, 28 and 29, respectively)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Considering that Δ0​>P, the magnetic moment (in BM) of [Ru(H2​O)6​]2+ would be ......... .

The pair in which both the species have the same magnetic moment (spin only) is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The overall stability constant of the complex ion [Cu(NH3​)4​]2+ is 2.1×1013. The overall dissociations constant is y×10−14. Then, y is ......... . (Nearest integer)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The calculated magnetic moments (spin only value) for species [FeCl4​]2−, [Co(C2​O4​)3​]3− and MnO42−​ respectively are

The correct order of magnetic moments (spin only values in BM) among the following is (At. no of Mn = 25, Fe = 26, Co = 27)

The sum of the spin only magnetic moment values (in B.M.) of $[Mn(Br)_{6}]^{3 -}$ and $[Mn(CN)_{6}]^{3 -}$ is ______.

The calculated spin only magnetic moments of $[Cr (NH_{3})_{6}]^{3 +}$ and $[CuF_{6}]^{3 -}$ in BM, respectively, are (Atomic numbers of Cr and Cu are 24 and 29, respectively)

Among $[Ni (CO)_{4}]$ , $[NiCl_{4}]^{2 -}$ , $[Co (NH_{3})_{4} Cl_{2}] Cl$ , $Na_{3} [CoF_{6}]$ , $Na_{2} O_{2}$ and $CsO_{2}$ , the total number of paramagnetic compounds is -

$M_{1}$ , $Q$ and $R$ , respectively are

Reagent $S$ is

The geometries of the ammonia complexes of $Ni^{2 +}$ , $Pt^{2 +}$ and $Zn^{2 +}$ , respectively , are :

Considering that $Δ_{0} > P$ , the magnetic moment (in BM) of $[R u (H_{2} O)_{6}]^{2 +}$ would be ......... .

The overall stability constant of the complex ion $[C u (N H_{3})_{4}]^{2 +}$ is $2.1 \times 1 0^{13}$ . The overall dissociations constant is $y \times 1 0^{- 14}$ . Then, $y$ is ......... . (Nearest integer)

The calculated magnetic moments (spin only value) for species $[FeCl_{4}]^{2 -}$ , $[Co (C_{2} O_{4})_{3}]^{3 -}$ and $MnO_{4}^{2 -}$ respectively are