Give the structure of `BeCl_2` in the solid state above 1200 K.

Explanation

(i) In solid state, Be atom is `sp^(3)` hybridised. Be atom is tetrahedrally surrounded by four Cl atoms.
Two chlorine atoms are bonded by covalent bonds and rest of two by co-ordinate bonds.
`BeCl_(2)` has polymeric chain structure and it is due to its electron deficient nature.

(ii) In vapour phase, `BeCl_(2)` exists as a dimer. here Be is `sp^(2)` hybridised. on dissociation of `BeCl_(2)` at 1000 K temperautre, it gives monomer in which Be atom is sp hybridised and has linear shape.