# What is the geometric formula of CaI2 and AlCl3

Well, I think $\ce{CaI2}$ is the same as $\ce{BeH2}$ and $\ce{AlCl3}$ the same as $\ce{NH3}$, but I'm not sure since $\ce{I}$ and $\ce{Cl}$ have their own pair electrons and I don't know if this affects the structure...

• Central atoms/cations are affecting geometry stronger than atoms they are connected with. Jan 28 '15 at 14:53

$\ce{CaI2}$ is mostly ionic in the solid and aqueous phases. In the gas phases it is a linear molecule. See Ionic or covalent? Can some first hints be derived from the solid state structures of alkaline earth metal halide adducts?
$\ce{AlCl3}$ has an octaheral structure in the solid phase.