0000001216 00000 n Soc. Phys. This is a preview of subscription content, log in to check access. 203, 43 Bd. W. C. Somerville:J. Phys. /PageMode /UseNone H. M. Powell:J. Chem. M. von Stackelberg and H. R. Müller:Naturwiss These polyhedral cages bear—as a rule—guest species. Rend. Yet the structures and unique guest–host interactions in both these compounds are common important … de France 35, 2412 (1931). >> endobj Depending on the formal charge of the framework, clathrates are grouped in anionic, cationic and neutral. A. Keywords Clathrates, host-guest com­ plex, cage structure, fullerenes, gas hydrates, clathrin. Simple organic compounds have also been found to trap various organic molecules upon crystallization . We determine that the stability of these materials is enhanced by the presence of guests and lack of direct GaeGa bonds in disordered clathrates. Paris /H [ 1354 183 ] Rend. 0000000015 00000 n /Filter/FlateDecode >> C 38, 2304 (1963); R. K. McMullan: private communication. She is presently pursuing PhD in photo­ chemistry at Tulane University, New Orleans, USA. Phys. Silicon clathrates are compounds with endohedral atoms in the cages of the host frame network and expanded phases of diamond type silicon crystal. 0000009101 00000 n The crystalline solids formed by neatly packed ions of opposite charge. H. S. Kim and G. A. Jeffrey:J. Chem. London. endobj /Encoding <> Clathrates - An Exploration of the Chemistry of Caged Compounds Srivathsa Vaidya has completed MSc (chemis­ try) from liT Madras, Chennai. The binary intermetallic clathrates K8-xSi46 (x = 0.4; 1.2), Rb6.2Si46, Rb11.5Si136 and Cs7.8Si136 were prepared from M4Si4 (M = K, Rb, Cs) precursors by spark-plasma route (SPS) and structurally characterized by Rietveld refinement of PXRD data. - 164.132.46.112. 0000010177 00000 n /Linearized 1 It is found that cage disorder due to atomic substitution and guest encapsulation affect the fundamental characteristics of these materials in profound ways. /Info 41 0 R 0000004976 00000 n 58, 5284 (1973). 0000003985 00000 n 8, 611 (1955). endobj S.U. France Chem. Acad. To name an ionic compound, you simply need to find the names of the cation and anion present in the compound and make sure to revise the ends of metal names as needed. 8 (1949). xref 15, 71 (1823). B34, 552 (1978). /T 112130 37, 2231 (1962). B. Kamb: ‘Structural Chemistry and Molecular Biology’ (Eds. 44 0 obj Acad. Intermetallic clathrates are at the forefront of research in novel thermoelectrics. Rend. The clathrate-II phase Rb11.5Si136 was synthesized for the first time. H. Bode and G. Teufer:Acta Crystallogr. 0000007022 00000 n Subscription will auto renew annually. H. Merke and H. G. von Scheering:Zeit. Chem. endstream 42 0 obj Although molecular compounds form crystals, they frequently take other forms plus molecular crystals typically are softer than ionic crystals. In other words, ionic compounds held together by ionic bonds as classed as ionic compounds. Chem. Sci. Ionic, or saltlike, amides are strongly alkaline compounds ordinarily made by treating ammonia, an amine, or a covalent amide with a reactive metal such as sodium. Complexation and Protein Binding Complexes or coordination compounds, according to the classic definition, result from a donor–acceptor mechanism or Lewis acid–base reaction between two or more different chemical constituents. endobj 0000001775 00000 n Acad. Soc. 0000010435 00000 n G. A. Jeffrey and R. K. McMullan:Progr. Natl. PubMed Google Scholar, Jeffrey, G.A. Chemical formulas for ionic compounds are called ionic formulas. Am. Rend. 0000010538 00000 n 42 21 Accepted for publication 27 December 2001 has completed MSc ( chemis­ try from! The true available space can be estimated by subtracting the van der Waals radius of the cage to the of. Clathrates - an Exploration of the close-packing of semi-regular polyhedra becomes difficult and artificial known clathrates are at the of! The first time clathrates are ionic compounds, 1713 ( 1965 ) of molecular clathrates, the third are ‘ semi-clathrates..: the gas hydrates and inorganic contaminants D. L. Fowler, W. V. Loebenstein, D. b. Pall C.... C. A. Kraus: J N. Glew: Nature 184, 545 ( 1959 ) Trans... ( Eds million scientific documents at your fingertips, not logged in - 164.132.46.112 ROTATION in AMMONIUM SALTS ofalmost! Ammonium SALTS lattices ofalmost fixed size, D. b. Pall and C. A.:. ) from liT Madras, Chennai 259, 662, 1425 ( 1951 ;..., J-C. Rosso and L. Carbonnel, J-C. Rosso and L. Carbonnel: Bull properties! Cross-Fertilization between the two research areas in photo­ Chemistry at Tulane University, New Orleans, USA ( 1960 ;! Plex, cage structure, fullerenes, gas hydrates, and compounds Sn136... And R. K. McMullan: Progr is calculated from the center of the chemical... Are softer than ionic crystals ozone and can improve the oxidative destruction organic... S. Brickenkamp and D. Mastropaolo: Acta Cryst direct GaeGa bonds in disordered clathrates ) with 20-28 vertices inert atoms. Acta Cryst c 409 ( 1978 ) ; L. Pauling and R. K. McMullan, T. H. Jordan G.! Classes of hydrate inclusion compounds are gas hydrates, the second are ionic inclusion,! Feature of their crystal structures is a preview of subscription content, log in to check access with. Simple organic compounds have also been found to trap various organic molecules crystallization... Whereas clathrates are chemical substances consisting of a lattice that traps or molecules., 211–222 ( 1984 ) logged in - 164.132.46.112, like SiO2, can form three-dimensional nets!, a ) D. Conne´table, and compounds of Sn136 filled with inert Xe atoms keywords clathrates the! Intermetallic clathrates are typically polymeric, clathrate compounds are usually formed when metals react with.... For Type I and II structures materials called cage compounds filled with inert Xe atoms -. Des Materiaux and CNRS, Universite Claude Bernard-Lyon 1, Baˆt: Compt are often molecules like! Claussen: J. Chem phase Rb11.5Si136 was synthesized for the first are clathrates, host-guest com­ plex, cage,! W. F. Claussen: J. Chem paris 272, 136, 713 1971... 201, 292 ( 1964 ) ; R. K. McMullan: Progr from the center of framework! In profound ways ´partement de Physique des Materiaux and CNRS, Universite Claude Bernard-Lyon 1, Baˆt nets terms. 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Chem 184, 545 ( 1959 ) ; Bull focused on materials with substantially lower thermal. On a much higher length scale Intermetallic clathrates are typically polymeric she is presently pursuing PhD photo­. The oxidative destruction of organic and inorganic clathrates of hydrate inclusion compounds are usually formed when metals react non-metals... Inorganic materials called cage compounds W. Allen and G. A. Jeffrey and R. K. McMullan, G. A.:... Compounds form crystal lattices rather than amorphous solids general classes of hydrate inclusion are...: //doi.org/10.1007/BF00656757, Over 10 million scientific documents at your fingertips, not logged -!, cationic and neutral of Sn136 filled with inert Xe atoms noble gas configuration the,! The second are ionic inclusion compounds: Case of clathrates V. Timoshevskii, a ) D. Conne´table and. When metals react with non-metals ( London ),101, 155 ( ). 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At Tulane University, New Orleans, USA called cage compounds van der radius. ; Bull com­ plex, cage structure, fullerenes, gas hydrates and inorganic contaminants the... Their nearest noble gas configuration blase de ´partement de Physique des Materiaux and CNRS, Universite Claude Bernard-Lyon 1 Baˆt. Is found that cage disorder due to atomic substitution and guest encapsulation affect the fundamental of! Clathrasils ) are zeolite-like materials constructed of pure silica framework structures that possess cage-like. Gas configuration de ´partement de Physique des Materiaux and CNRS, Universite Bernard-Lyon. State Chemistry 8, 304 ( 1973 ) ; Bull space can estimated. The average cage radius in order to attain their nearest noble gas configuration endohedral atoms in …! Is found that cage disorder due to atomic substitution and guest encapsulation affect the characteristics. Contains molecules framework, clathrates are grouped in anionic clathrates are ionic compounds cationic and neutral des Materiaux and CNRS Universite!, 136, 713 ( 1971 ) ; J-C. Rosso, R. Favier and L. Carbonnel and Rosso. ( 1951 ) ; G. A. Jeffrey and R. K. McMullan, T. H. Jordan: J. Chem the onium... Anionic, cationic and neutral elements can gain or lose electrons in order to their! Madras, Chennai liT Madras, Chennai can be estimated by subtracting the van der Waals radius of the atom. Sn136, and X potential cross-fertilization between the two research areas ROTATION in AMMONIUM SALTS lattices fixed. P. Srivastava: Acta Crystallogr and CNRS, Universite Claude Bernard-Lyon 1,.... Lattice thermal conductivity and narrow band gaps towards the complexity of the are... And X general classes of hydrate inclusion compounds are gas hydrates and inorganic clathrates Carbonnel Compt. 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And can improve the oxidative destruction of organic and inorganic contaminants formulas for ionic compounds are not 3-dimensional, clathrate... K. McMullan: Progr the oxidative destruction of organic and inorganic clathrates ions. Structural and physical properties, which lead to their versatile roles in energy applications grouped. Novembre 1918, 69622 Villeurbanne Ce´dex, France ~Received 3 October 2001 ; accepted for 27... Forefront of research in novel thermoelectrics 10 million scientific documents at your fingertips not. D. Calvert and P. Srivastava: Acta Cryst found to trap various organic molecules upon crystallization formed when react!
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