What is the structure of $BeCl_2$ molecule in gaseous and solid state?

(N/A) In the solid state,$BeCl_2$ has a polymeric chain-like structure. Each $Be$ atom is surrounded by four $Cl$ atoms,where two $Cl$ atoms are bonded through covalent bonds and the other two are bonded through coordinate bonds. This is shown in structure $A$.
In the gaseous state,beryllium chloride exists as a dimer $(Be_2Cl_4)$ at lower temperatures,which has a bridged structure. At high temperatures (about $1200 \ K$),it dissociates into a monomer $(BeCl_2)$,which is linear in structure. This is shown in structure $B$.