Title: Clathrates
Literature References: Compounds that are capable of trapping other substances within their own crystal lattices. The cavities of the host molecules are classified as cages, tunnels, or layered types, depending on the way they include guest molecules. The geometry of the cavities limits the guest molecules by size and shape, rather than by chemical similarity with the host molecules. Among common clathrates are molecular sieves, cyclotriphosphazenes, and Dianin's compound, as well as hydroquinone, cyclodextrins, and deoxycholic acid, q.q.v. Cavitands are organic hosts with enforced (rigid) cavities: D. J. Cram, Science 219, 1177 (1983); R. C. Helgeson et al., Chem. Commun. 1983, 101. Comprehensive book: Clathrate Compounds, V. M. Bhatnagar, Ed. (Chemical Pub. Co., New York, 1970) 244 pp. Reviews: D. D. MacNicol et al., Chem. Soc. Rev. 7, 65-87 (1978); E. C. Makin, "Clathration" in Kirk-Othmer Encyclopedia of Chemical Technology Vol. 6 (Wiley-Interscience, New York, 3rd ed., 1979) pp 178-189.
Use: As complexing agent; stabilizing agent. In analytical separations.
Clavulanic Acid Clazosentan Clazuril Clebopride Clemastine

A clathrate is a chemical substance consisting of a lattice that traps or contains molecules. The word clathrate is derived from the Latin clatratus meaning with bars or a lattice.[1] Traditionally, clathrate compounds are polymeric and completely envelop the guest molecule, but in modern usage clathrates also include host-guest complexes and inclusion compounds.[2] According to IUPAC, clathrates are "Inclusion compounds in which the guest molecule is in a cage formed by the host molecule or by a lattice of host molecules."[3]

Structure of the 3:1 inclusion complex of urea and 1,6-dichlorohexane. The framework is composed of molecules of urea that are linked by hydrogen bonds, leaving approximately hexagonal channels into which align the molecules of the chlorocarbon. Color scheme: oxygen is red, nitrogen is blue, chlorine is green.[4]