Question

What would be the structure of `ICl_2^(-)` ion?

Answer 1

Is the ion not linear? Electronic geometry is trigonal bipyramidal.

Explanation:

There are `3xx7_"valence electrons"+1_"negative charge"=22*"electrons"` to arrange over three centres. And, typically, we put the LEAST electronegative atom centrally...

And so....`Cl-I-Cl`, from left to right, chlorine has 1 bonding pair and bears 3 lone pairs, iodine has 2 bonding pairs, and bears 3 lone pairs, and the terminal chlorine has bonding pair and bears 3 lone pairs, as before.

Because iodine is associated with EIGHT electrons, i.e. 3 lone pairs, and it is assigned 2 bonding electrons, it bears a FORMAL negative charge. The chlorine atoms are each associated with 7 electrons, and hence these centres are formally neutral.