Subjective Type

Why a solution of $$[Ni(H_2O)_6]^{2+}$$ is green while a solution of $$[Ni(CN)_4]^{2-}$$ is colourless? (At no. of $$Ni=28$$)

Solution

In $$[Ni(H_2O)_6]^{2+}, Ni$$ is in $$+2$$ oxidation state with the configuration $$3d^8 4s^0$$, i.e., it has two unpaired electrons which do not pair in the presence of weak $$H_2O$$ ligand. The $$d-d$$ transition absorbed red light and the complementary green light is emitted.
On the other hand, in $$[Ni(CN)_4]^{2-}, Ni$$ is again in $$+2$$ oxidation state with the the electronic configuration $$3s^8$$. In the presence of strong $$CN^-$$ ligand the two unpaired electrons in the $$3d$$ orbitals pair up. As there is no unpaired electron in $$[Ni(CN)_4]^{2-}$$, therefore the complex is colourless.

SIMILAR QUESTIONS

Coordination Compounds

Among the following, the species that is both paramagnetic and coloured is :

Coordination Compounds

What is the relationship between observed color of the complex and the wavelength of light absorbed by the complex?

Coordination Compounds

The colourless species is:

Coordination Compounds

Which of the following compound is expected to be colourless?

Coordination Compounds

Which of the following compounds is not colored yellow?

Coordination Compounds

Which of the following statements is/are correct?

Coordination Compounds

Which of the following is correct about $$\underset{I}{KFe^{II}[Fe(CN)_6]}$$ and $$\underset{II}{KFe^{III}[Fe(CN)_6]}$$ complex compounds?

Coordination Compounds

If $$MCl_2$$ salt is white, then comment on colour of its iodide salt.

Coordination Compounds

Choose incorrect statement.

Coordination Compounds

Answer the following question: $$[Ni(H_2O)_6]^{2+}$$ is green whereas $$[Ni(CN)_4]^{2-}$$ is colourless. Why? (At no. of $$Ni=28$$)

Contact Details