# Why doesn't CO_2 melt if you leave it out in the open?

$C {O}_{2}$ is a non polar molecule and therefore, the only possible intermolecular interactions are London Dispersion Force (LDF) or also called Van der Waals forces which are considered weak forces, especially that $C {O}_{2}$ is a small molecule.
When $C {O}_{2}$ solid (dry ice) is heated (or left in the open air at ${25}^{\circ} C$), most of the intermolecular forces will break and $C {O}_{2}$ molecules will be free and will become gaseous molecules.