A Syngas, or synthesis gas, is a gas mixture that is mainly used for synthesis. In the broad sense of the term, this can be any synthesis, such as the synthesis of Nitrogen, Hydrogen, or Ammonia. In the narrow sense of the word, only gas mixtures are covered, where the main component are carbon monoxide, and hydrogen.

Common uses of such gases are:

• production of Methanol
• using the Haber process to produce Ammonia
• Hydroformylation, also called the oxo process.
• The Fischer–Tropsch process