Question

How many isomers are possible for `[Cr(NO_2)(NH_3)_5]Cl_2`?

Answer 1

A couple, but there is of course a catch.......

Explanation:

For the complex ion `[Cr(NO_2)(NH_3)_5]^(2+)`, only the one isomer would be available but for the ambident nature of the ligand, `NO_2^-`.

`"Nitro-nitrito"` isomerism can occur, depending on whether the ligand is `"N-bound, nitro"` or `"O-bound, nitrito"`; and thus 2 isomers are possible. The `NO_2^-` ligand can also bind in a chelate fashion, but I doubt it is doing so in a co-ordinatively saturated `Cr(III+)` complex.