Tag: metal carbonyls

Questions Related to metal carbonyls

Which of the following does not have a metal-carbon bond.

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. ${C} _{2}{H} _{5}MgBr$

  2. $K[Pt({C} _{2}{H} _{4}){Cl} _{2}]$

  3. $Ni{(CO)} _{4}$

  4. $Al{(O{C} _{2}{H} _{5})} _{3}$

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Correct Option: D

Which of the following is correct value of n in ${\text{Cr}}\left( {{\text{CO}}} \right){\text{n}}$

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. 2

  2. 4

  3. 6

  4. Unpredictable

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Correct Option: A

Which of the following is correct?

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. $H _{3}PO _{3}$ is dibasic and reducing

  2. $H _{3}PO _{3}$ is dibasic and non-reducing

  3. $H _{3}PO _{4}$ is tribasic and reducing

  4. $H _{3}PO _{3}$ is tribasic and non-reducing

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Correct Option: B

Which of the following organometallic compound

is $\sigma $ and $\pi $ bonded?

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. $[Fe(\eta ^{5}-C _{5}H _{5}) _{2}]$

  2. $[PtCl _{3}(\eta ^{2}-C _{2}H _{4})]$

  3. $[Co(CO) _{5}NH _{3}]^{2+}$

  4. $Al(CH _{3}) _{3}$

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Correct Option: C
Explanation:

$[PtCl _{3}(\eta ^{2}-C _{2}H _{4})]$ and $[Fe(\eta ^{5}-C _{5}H _{5}) _{2}]$ are pi bonded organometallic compound.

$Al(CH _3) _3$ 
is sigma bonded organometallic compound.
$[Co(CO) _{5}NH _{3}]^{2+}$ is sigma and pi bonded organometallic compound.

Which of the following organometallic compound is $\sigma$ and $\pi$ bonded -

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. $[Fe(\eta^{5} - C _5H _5) _2]$

  2. $K[PtCl _3(\eta^{2} - C _2H _40]$

  3. $[Co(CO) _5NH _3]^{+2}$

  4. $Fe(CH _3) _3$

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Correct Option: C
Explanation:
Option (C) is correct.
$[Co(CO) _5NH _3]^{+2}$ is $\sigma$ and $\pi$ bonded.
In this organometallic compound,bond between cobalt and $CO$ ligands have both $\sigma$ and $\pi$ character.$\sigma$- bond formation between metal and carbon of $CO$ takes place by overlap of filled bonding $\pi _{2p}$ of $CO$ with an empty metal $d$- orbital.
The 2nd overlap takes place between metal $d$- orbital with an empty antibonding pi orbital of the $CO$ resulting in additional $\pi$- bond between the metal and same $CO$ molecule. 

Which of the following metal(s) form(s) polynuclear carbonyl?

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. Na

  2. Mg

  3. Mn

  4. Al

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Correct Option: C
Explanation:

Manganese forms poly nuclear carbonyl.  


Polynuclear metal carbonyls are generally found in late transition metals with low formal oxidation states.

Option C is correct.

Which of the following complex ion has least stability ?

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. $[Co(NH _2) _6]^{2+}$

  2. $[Co(CN) _6]^{3-}$

  3. $[Co(NH _3) _6]^{3+}$

  4. $[Co(CO) _6]^{3+}$

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Correct Option: D
Explanation:

Cobalt with odd atomic number $(=27)$ does not form a monometallic carbonyl compound. Thus, $[Co(CO) _6]^{3+}$ is least stable among the given.

Which of the following does not have a metal-carbon bond:

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. $C _{2}H _{5}MgBr$

  2. $K\left [ Pt \left ( C _{2}H _{4} \right ) Cl _{3}\right ]$

  3. $Ni\left ( CO \right ) _{4}$

  4. $Al\left ( OC _{2}H _{5} \right ) _{3}$

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Correct Option: D
Explanation:

Chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal.

$C _2H _5MgBr$ is a $\sigma$-bonded complexes.
$K[Pt(C _2H _4)Cl _3]$ contains a bond between carbon and potassium which is a metal.
$Ni(CO) _4$ also contains metal-carbon bond as it is itself a metal carbonyl.

Which of the following statement(s) is/are true?

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. In metal carbonyl complexes $d _{C-O}$ increases compared to that in CO molecule

  2. The pair of compounds $[Cr(H _2O) _6]Cl _3$ and $[CrCl _3(H _2O) _3]\cdot 3H _2O$ show hydrate isomerism.

  3. $d _{z^2}$ orbital of central metal atom/ion is used in $dsp^2$ hybridisation.

  4. Facid and Meridional isomers associated with $[Ma _3b _3]^{n\pm}$ type complex compound, both are optically inactive.

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Correct Option: A,D
Explanation:

(A) Metal carbonyls involve synergic bonding $(M\underset {\sigma}{\overset {\pi}\rightleftharpoons } L)$. Filled metal d orbital overlaps with antibonding pi orbital of CO. Thus the bond order and bond length in CO decreases.
Thus option A is correct.
(B) $[CrCl _3(H _2O) _3]\cdot 3H _2O$ is not a hydrate isomer of $[Cr(H _2O) _6]Cl _3$.
Thus option B is incorrect.
(C) The d-orbitals involved in s$sp^3d^2  and\  d^2sp^3$  hybridisation of the central metal ion are $d _{x^2-y^2}$  and  $d _{z^2}$ respectively.
Thus option C is incorrect.
(D) Both fac and mer isomers of $[Ma _3b _3]^{n\pm}$ are optically inactive as they contain plane of symmetry.
Thus option D is correct.

Select the correct order of C-O bond order in mixed phosphine carbonyl complex :

chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

  1. $[(Ph _3P) _3Mo(CO) _3] > [(Ph _2PCl) _3Mo(CO) _3] > (PhPCl _2) _3 Mo (CO) _3]$

  2. $[(Ph _3P) _3Mo(CO) _3] > [(Ph _2PCl) _3Mo(CO) _3] < (PhPCl _2) _3 Mo (CO) _3]$

  3. $[(Ph _3P) _3Mo(CO) _3] = [(Ph _2PCl) _3Mo(CO) _3] > (PhPCl _2) _3 Mo (CO) _3]$

  4. $[(Ph _3P) _3Mo(CO) _3] < [(Ph _2PCl) _3Mo(CO) _3] > (PhPCl _2) _3 Mo (CO) _3]$

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Correct Option: B
Explanation:

As phenyl group increases, resonance increases and bond length increases so order is
$[(Ph _3P) _3Mo(CO) _3] > [(Ph _2PCl) _3Mo(CO) _3] < (PhPCl _2) _3 Mo (CO) _3]$