Bonds antimony-halogen

Exchange of antimony-carbon bonds with antimony-halogen bonds in triphenylantimony and antimony trichloride upon heating at 250° C for 75 hours has been utilized for the preparation of phenylantimony chlorides (108,109). Also exchange of vinyl groups with chlorine atoms on antimony has been observed (155). Recently, however, a quantitative study of the kinetics of the reaction between trimethylantimony and antimony trichloride has been reported (298), details of which have been discussed in Section IV, A,1. 

Relatively little is known of the chemistry of antimony rings compared to arsenic rings. The reactions of arsenic homocycles have been reviewed several times " . They include cleavage of the As—As bonds with halogens and insertion of chalcogens or unsaturated hydrocarbons and reductive cleavage with potassium metal. Representative examples are given in equations 15-18. 

Bonds to Halogen.—Antimonyim) Compounds. Vapour-pressure data and values of the sublimation enthalpy have been obtained for antimony trifluoride and bismuth trifluoride, using a method based on differential calorimetry combined with the Knudsen effusion technique. The vapour-pressure equations for SbF3 and Bip3 are, respectively ... 

The magnetic criterion is particularly valuable because it provides a basis for differentiating sharply between essentially ionic and essentially electron-pair bonds Experimental data have as yet been obtained for only a few of the interesting compounds, but these indicate that oxides and fluorides of most metals are ionic. Electron-pair bonds are formed by most of the transition elements with sulfur, selenium, tellurium, phosphorus, arsenic and antimony, as in the sulfide minerals (pyrite, molybdenite, skutterudite, etc.). The halogens other than fluorine form electron-pair bonds with metals of the palladium and platinum groups and sometimes, but not always, with iron-group metals. 

The 8-N rule states that the number of bonds (or local coordination, x) equals 8 minus the number of the periodic group. This rule is illustrated in Fig. 1.2 where we see that for N — 7 the halogens take dimeric structure types with x = 1, for N = 6 the chalcogenides selenium and tellurium take helical chain structures with x = 2, for N = 5 the pnictides arsenic, antimony, and bismuth take a puckered layer structure with x = 3, and for N = 4 the semiconductors... 

Replacement of Halogens by Fluorine and Addition of Fluorine to C = C Bonds with Antimony(V) Fluoride and Fluoroantimonates... 

The chemistry of antimony and nitrogen is not as rich as that of arsenic and nitrogen. The N—Sb bond mainly exists in compounds where N is but one of a number of donor atoms. These compounds, where significant, will be dealt with under various other headings (mainly oxo and halogen ligands). Some Sb—N bond data are assembled in Table 12. 

Compounds XXI were characterized as stable tetraphenylboratc salts, which are thought to be a type of stibonium that contains Fe—Sb compounds containing halogen groups bonded to the antimony atom were prepared recently by the reaction of [Cp(CO)2Fe3i or Cp(CO)2FeNa with SbX3 (58, 59). 

Of the solvents, aromatic and olefinic hydrocarbons are r-donors ( r-EPD) alcohols, ethers, amines, carboxamides, nitriles, ketones, sulfoxides and N- and P-oxides are n-donors (n-EPD), and haloalkanes are cr-donors (cr-EPD). Boron and antimony triha-lides are acceptor solvents (r-EPA), as are halogens and mixed halogens (c-EPA), and liquid sulfur dioxide (ti-EPA). In principle, all solvents are amphoteric in this respect, i.e. they may act as a donor (nucleophile) and an acceptor (electrophile) simultaneously. For example, water can act as a donor (by means of the oxygen atom) as well as as an acceptor (by forming hydrogen bonds). This is one of the reasons for the exceptional importance of water as a solvent. 

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