SbF₅ reacts with XeF₄ to form an adduct. The shapes of cation and anion in the adduct are respectively:

XeF₄ is xenon tetrafluoride reacts with SbF₅ [Lewis acid] to form an adduct. 

${\mathrm{XeF}}_4+{\mathrm{SbF}}_5⟶\underset{\mathrm{T}-\mathrm{shape} }{{\left[{\mathrm{XeF}}_3\right]}^{+}}\underset{\mathrm{octahedral}}{{\left[{\mathrm{SbF}}_6\right]}^{-}}$

 ${\left[{\mathrm{XeF}}_3\right]}^{+}$ is T-shaped and ${\left[{\mathrm{SbF}}_6\right]}^{-}$is octahedral.