Q. If $I_2$ is dissolved in aqueous $KI$, the intense yellow species $I_3^-$ is formed. The structure of $I_3^-$ ions is
Delhi UMET/DPMTDelhi UMET/DPMT 2009Chemical Bonding and Molecular Structure
Solution:
Total number of valence electrons in $I_3^- = 7 \times 3 + 1= 22$.
In triiodide ion, the central iodine atom is $sp^3 d$ hybridised and has trigonal bipyramidal structure in which the equatorial positions are occupied by lone pairs and the axial positions by iodine.
