Can you turn a solid into a gas?

Under certain circumstances, gas can transform directly into a solid. This process is called deposition. Water vapor to ice - Water vapor transforms directly into ice without becoming a liquid, a process that often occurs on windows during the winter months. read more

A solid can turn directly into a gas through a process called sublimation. In this instance, the solid vaporizes without going through the intermediary liquid stage. For example, in the water cycle, this would involve snow or ice turning directly into water vapor without going through the melting process. read more

Now for your question. That evaporation of a solid into a gas can be reversed and the gas turned directly back into a solid without first becoming liquid. As long as the gas itself is at a low enough pressure it can be turned directly into a solid by cooling it to a low enough temperature. read more