THE OCCURRENCE OF GAS HYDRATES IN THE SOLAR SYSTEM

Abstract

The gas hydrates, which are clathrate compounds of gases in a (cubic) ice matrix, are not known to occur naturally on the earth because of the unfavorable com-bination of temperatures, pressures, and gases that are poor hydrate formers in the earth's atmosphere. Mixed hydrates of methane, ethane, and propane do occur in natural gas pipelines,1 and the solid hydrate can block the pipe if the water is not removed from the natural gas before pumping through the pipe. The factors which prevent the natural occurrence of the gas hydrates on the earth do not apply to other parts of the solar system, and it will be shown here that these hydrates may play a significant role in the chemistry of the solar system. Properties of the Gas Hydrates.-The gas hydrates are known to occur in two forms (for reviews see refs. 2, 3). Structure I hydrates have a cubic unit cell 12.0 A on edge containing 46 water molecules and 8 cavities. There are two smaller cavities of 3.95 A radius which can encage molecules with diameters of .1 A or less, and six larger cavities of 4.30 Ai radius which can encage molecules