Clathrate hydrates, also known as combustible ice, are crystalline inclusion compounds in which guest molecules such as methane, ethane, and carbon dioxide are trapped within water cages formed by hydrogen bonded networks of water molecules. In nature, vast deposits of natural gas hydrates exist and initially attracted enormous attention due to their value as energy resources. Recently, artificially synthesized clathrate hydrates have attracted attention as enabling materials in green processes: they can store gaseous energy (e.g., hydrogen) and facilitate the capture and sequestration of greenhouse gases.