Which of the following pairs of compounds is isoelectronic and isostructural?

1. ${\mathrm{BeCl}}_{\mathrm{2}},\hspace{0.17em}{\mathrm{XeF}}_{\mathrm{2}}$
2. ${\mathrm{TeI}}_{\mathrm{2}},\hspace{0.17em}{\mathrm{XeF}}_{\mathrm{2}}$
3. ${\mathrm{IBr}}_{\mathrm{2}}^{\mathrm{-}},\hspace{0.17em}{\mathrm{XeF}}_{\mathrm{2}}$
4. ${\mathrm{IF}}_{\mathrm{3}},\hspace{0.17em}{\mathrm{XeF}}_{\mathrm{2}}$

Solution

(i) ${\text{IBr}}_2^{-}$

number of the electron in the valence shell $=7+7+7+1=22$
(ii) ${\text{BeCl}}_{\text{2}}$

${\text{sp}}^{\text{3}}\text{d}$ hybridised (linear).
Number of the electron in the valence shell $=2+7+7=16$
(iii) ${\text{XeF}}_{\text{2}}$

number of electron in valence shell $=$$8+7+7=22$
(iv) ${\text{TeI}}_{\text{2}}$

number of the electron in the valence shell $\text{= 6+7+7=24}$
(v) ${\text{IF}}_{\text{3}}$

number of the electron in the valence shell $=7+7+7+7=28$
${\text{IBr}}_2^{-}$ and ${\text{XeF}}_{\text{2}}$ both are isostructural and isoelectronic.

Asked in: NEET 2017

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