Clathrate Hydrates

Abstract

The clathrate hydrates represent a distinctive, unusual, scientifically significant, and practically important class of solid state materials. Since their discovery in the early nineteenth century, their widespread distribution in oceans and permafrost regions and their ability to trap atoms and small molecules-particularly methane and other small hydrocarbons-has led to the realization that they are simultaneously a tremendous energy source and, in the face of global warming, a potential greenhouse gas release disaster of unprecedented magnitude just waiting to happen. In the twentieth century, it was realized that solid methane clathrate hydrate could plug natural gas pipelines and disrupt oil drilling processes. On the environmental positive side, clathrate hydrates can store hydrogen and sequester carbon dioxide. A brief historical review of the formation, structure, and uses of clathrate hydrates forms the backdrop for a discussion of modern scientific investigations of these solids employing spectroscopy, structure determination methods, isotopic studies, computational-theoretical modeling, and interrogations of guest-host interactions via special guests. For example, the use of colored halogens in clathrate hydrate hosts enables UV-visible spectroscopic methods to be employed to study clathrate hydrate structure.

Investigating states of gas in water encapsulated between graphene layers

“…The clathrate state detected here in GLCs differs from typical gas clathrates (gas hydrates), 33–35 which have been studied for many decades. The latter exist at temperatures well below room temperature and at pressures considerably higher than 1 atm; the former exist under ambient conditions.…”

Colored Wastewater Treatment by Clathrate Hydrate Technique

“…However, it was in the 20th century that researchers discovered that solid methane clathrate hydrate might clog natural gas pipes and interfere with oil drilling operations. Clathrate hydrates have certain environmentally beneficial properties, such as the ability to store hydrogen and sequester carbon dioxide [23].…”

Delving into guest-free and He-filled sI and sII clathrate hydrates: a first-principles computational study

“…8 The stability of these complexes arises from the hydrogen bonds established between water molecules and the van der Waals (vdW) dispersion forces between host and guest species. 9,10…”

“…8 The stability of these complexes arises from the hydrogen bonds established between water molecules and the van der Waals (vdW) dispersion forces between host and guest species. 9,10 The three most common clathrate hydrates structures adopted naturally are the cubic sI and sII lattices and the hexagonal sH. What distinguishes them is the size, shape and number of water cages present in each of the structures, as well as the periodic crystal structure.…”