Multiple Choice

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

ATotal number of valence shell electrons at metal centre in $$Fe(CO)_5$$ or $$Ni(CO)_4$$ is $$16$$.
BThese are predominantly low spin in nature.
Correct Answer
CMetal-carbon bond strengthens when the oxidation state of the metal is lowered.
Correct Answer
DThe carbonyl $$C - O$$ bond weakens when the oxidation state of the metal is increased.

Solution

(A) $$[Fe(CO)_5]$$ & $$[Ni(CO)_4]$$ complexes have $$8$$-electrons in their valence shell (4th shell).
(B) Carbonyl complexes are predominantly low spin complexes due to strong ligand field.
(C) As electron density increases on metals (with lowering oxidation state on metals), the extent of synergic bonding increases. Hence $$M-C$$ bond strength increases.
(D) While positive charge on metals increased and the extent of synergic bond decreases and hence $$C-O$$ bond becomes stronger.

SIMILAR QUESTIONS

Coordination Compounds

Which of the following is paramagnetic?

Coordination Compounds

$$2.76 g$$ of silver carbonate on being strongly heated yields a residue weighing:

Coordination Compounds

Which of theses statements about $$[Co(CN)_6]^{3-}$$ is true?

Coordination Compounds

$$[Fe(CN)_6]^{-3}$$ is low spin complex but $$[Fe(H_2O)_6]^{+3}$$ is high spin complex. Explain.

Coordination Compounds

The correct statement about the magnetic properties of $$[Fe(CN)_6]^{3-}$$ and $$[FeF_6]^{3-}$$ is $$(Z=26)$$:

Coordination Compounds

Three complexes, $$[CoCl(NH_3)_5]^{2+} (I)$$, $$[Co(NH_3)_5H_2O]^{3+} (II)$$ and $$[Co(NH_3)_6]^{3+}(III)$$ absorb light in the visible region. The correct order of the wavelength of light absorbed by them is:

Coordination Compounds

Which of the following facts about the complex $$[{C}{r}({N}{H}_3)_{6}]{C}l_{3}$$ is wrong?

Coordination Compounds

Which of the following will form an octahedral complex?

Coordination Compounds

For the octahedral complexes of $$\displaystyle Fe^{3+}$$ in $$\displaystyle SCN^{-}$$ (thiocyanato-$$S$$) and in $$\displaystyle CN^{-}$$ 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]

Coordination Compounds

Low spin tetrahedral complexes are not formed because:

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