Which of the Three Complexes Can Have Geometric Isomers?

Your second and fourth compounds... they don't exist.

(i)

• Platinum does class square planar complexes, so this is real.
• Since it has two equivalents for each of two different species, this tin can have cis/trans isomers, i.e. geometric isomers.

Therefore, diamminedichloroplatinum(II) has geometric isomers.

(3)

This looks real.

• #"Ni"^(2+)# has a common coordination number of #6#, and along with the 3 #"Cl"^(-)# ligands, the total charge is #-1#.

• This is an #Ma_3b_3# octahedral complex, so information technology tin can have 2 isomers only: fac and mer. Refer to this answer for more than information.

• fac and mer isomers are actually diastereomers, which are a subset of geometric isomers (at least, according to this website!).

So, they count as geometric isomers, and triamminetrichloronickel(Two) has a fac and mer geometric isomer.

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(ii)

I don't recall your 2d compound is correct. #"Cu"^(+)# has x #3d# electrons, which would mean it fills the #d_(10^2-y^two)# antibonding orbitals, destabilizing the complex's #"Cu"-"50"# bonds.

However, #"Cu"^(2+)# has 1 less #3d# electron, giving less antibonding character to the #"Cu"-"L"# bond, making #["Cu"("NH"_3)_3"Cl"]^(+)# more (thermodynamically) stable than #"Cu"("NH"_3)_3"Cl"#.

Indeed, the common coordination number for #"Cu"^(2+)# is #four#, whereas that of #"Cu"^(+)# is #2#. Either way, this chemical compound doesn't have ii equivalents of each of two species, and then information technology has no geometric isomers.

Oh yeah, and your compound probably doesn't exist either.

(4)

This compound is not real either. #"Co"^(3+)# in this chemical compound would have a mutual coordination number of #half dozen#, non #seven#.

Notwithstanding, #"Co"("NH"_3)_4"Cl"_2# would exist. It does have geometric isomers, though it's #"Co"^(2+)# instead.

The trans isomer would have axial #"Cl"# ligands, and the cis isomer would commutation an axial #"Cl"# with an equatorial #"NH"_3#.

wonghation.blogspot.com

Source: https://socratic.org/questions/which-of-the-following-coordination-compounds-have-geometric-isomers