Chemical Bonding - Result Question 91
####67. Among the triatomic molecules/ions $BeCl _2, N _3^{-}, N _2 O, NO _2^{+}$, $O _3, SCl _2, ICl _2^{-}, I _3^{-}$and $XeF _2$, the total number of linear molecules(s)/ion(s) where the hybridisation of the central atom does not have contribution from the $d$-orbital(s) is [atomic number of $S=16, Cl=17, I=53$ and $Xe=54$ ]
(2015 adv.)
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Solution:
$$ \begin{aligned} & N \equiv \underset{\substack{\uparrow \ s p}}{N} \rightarrow \ddot{O} \bullet \quad O=\underset{\substack{\uparrow \ s p}}{\stackrel{+}{N}}=O \end{aligned} $$
All the above mentioned molecules/ions have $s p$-hybridised central atom and no one pair at central atom, hence linear also. Others are :
$$ \begin{aligned} & {\left[\begin{array}{cc} \left.I-\ddot{I} _{\bullet}^{i}-I\right]^{-} & F-\ddot{X} _{\bullet}^{\stackrel{\bullet}{\uparrow}}-F \ s p^{3} d \text {-linear } & s p^{3} d \text {-linear } \end{array}\right.} \end{aligned} $$
[Although $ICl _2^{-}, \Gamma _3$ and $XeF _2$ all also are linear but in them $d$-orbital contribute in hybridisation.]
