ⓘ Hydrogen clathrate

                                     

ⓘ Hydrogen clathrate

A hydrogen clathrate is a clathrate containing hydrogen in a water lattice. This substance is interesting due to its possible use to store hydrogen in a hydrogen economy. A recent review that accounts the state-of-the-art and future prospects and challenges of hydrogen storage as clathrate hydrates is reported by Veluswamy et al. Another unusual characteristic is that multiple hydrogen molecules can occur at each cage site in the ice, one of only a very few guest molecule that forms clathrates with this property. The maximum ratio of hydrogen to water is 6 H 2 to 17 H 2 O. It can be formed at 250K in a diamond anvil at a pressure of 300MPa. It takes about 30 minutes to form, so this method is impractical for rapid manufacture. The percent of weight of hydrogen is 3.77%. The cage compartments are hexakaidecahedral and hold from two to four molecules of hydrogen. At temperatures above 160K the molecules rotate around inside the cage. Below 120K the molecules stop racing around the cage, and below 50K are locked into a fixed position. This was determined with deuterium in a neutron scattering experiment.

Under higher pressures a 1:1 ratio clathrate can form. It crystallises in a cubic structure, where H 2 and H 2 O are both arranged in a diamond lattice. It is stable above 2.3 GPa.

Under even higher pressures over 38 GPa there is a prediction of the existence of a clathrate with a cubic structure and a 1:2 ratio: 2H 2 H 2 O.

More complex clathrates can occur with hydrogen, water and other molecules such as methane, and tetrahydrofuran.

Since hydrogen and water ice are common constituents of the universe, it is very likely that under the right circumstances natural hydrogen clathrates will be formed. This could occur in icy moons for example. Hydrogen clathrate was likely to be formed in the high pressure nebulae that formed the gas giants, but not to have formed in comets.

                                     
  • self - associate by multiple hydrogen - bonding interactions. The most famous clathrates are methane clathrates where the hydrogen - bonded framework is contributed
  • pressure hydrogen clathrate for hydrogen storage. Forming hydrogen clathrate hydrate requires very high pressures, but by starting with nitrogen clathrate multiple
  • are trapped inside cages of hydrogen bonded, frozen water molecules. In other words, clathrate hydrates are clathrate compounds in which the host molecule
  • The clathrate gun hypothesis refers to a proposed explanation for the periods of rapid warming during the Quaternary. The idea is that changes in fluxes
  • the extracellular matrix. Clathrate hydrates are a class of solids in which gas molecules occupy cages made up of hydrogen - bonded water molecules. These
  • SF Marsh, KN Sloan, ED 2004 Stable Low - Pressure Hydrogen Clusters Stored in a Binary Clathrate Hydrate Science. 306 5695 469 71. Bibcode: 2004Sci
  • carbons including CNTs MOFs, and hydrogen clathrate hydrate. Underground hydrogen storage is the practice of hydrogen storage in caverns, salt domes and
  • there is no hydrogen bonding between water and guest molecules when methane is the guest molecule of the clathrate guest host hydrogen bonding often
  • methane is the guest molecule of the clathrate guest - host hydrogen bonding often forms with guest molecules in clathrates of many larger organic molecules
  • Salke, Nilesh P. May 2018 Synthesis of clathrate cerium superhydride CeH9 below 100 GPa with atomic hydrogen sublattice Nature Communications. 10 1
  • derivatives. Hydrogen Cycle Industrial gas Lake Kivu more general: limnic eruption List of straight - chain alkanes Methanation Methane clathrate ice that