Whirh of the following statements is correct for $\mathrm{Ni}(\mathrm{CO}{)}_4\text{ and }{\left[\mathrm{Co}(\mathrm{CO}{)}_4\right]}^{-}$ ?

Isostructural 

The atoms match in place and function, despite the fact that there may not be a close chemical link, making the crystal structure isostructural. utilised for crystallised materials such as minerals. The isostructural compounds of calcite and sodium nitrate.

isoelectronic:

Elements or ions with an identical amount of electrons are referred to as isoelectronic species.

 $\mathrm{Ni}(\mathrm{CO}{)}_4\text{ and }{\left[\mathrm{Co}(\mathrm{CO}{)}_4\right]}^{-}$ Both are Isostructural and isoelectronic