Carbon dioxide
At usual pressure it will not melt from a solid to a liquid but instead changes directly from a solid to a gas. This is called sublimation. It will change directly from a solid to a gas at any temperature higher than extremely cold temperatures. Dry ice sublimates at normal air temperature. Dry ice exposed to normal air gives off carbon dioxide gas that has no color. Carbon dioxide can be liquified at pressure above 5.1 atmospheres.