Bonds to Halogens

Bonds to Halogen.—Microwave studies of four isotopic species of NC13 have been used to calculate the structural parameters [r(N—Cl)= 1.7535 0.0020 A, and angle C1NC1 = 107°47 20 ], the dipole moment (fx =0.39 0.01 D), and the N—Cl bond-axis quadrupole coupling constant (-108 3 MHz).179 

From a conductance study of the effect of NOC1 on S03 in S02 at —20 °C, the compounds N0(S03) C1 (n = 1, 2, or 3) have been isolated. It would appear from conductivity data that N0S03C1 behaves as a weak electrolyte in SO2.1S0 The kinetics of atom-exchange reactions among C1NO, NO, and N02 have been studied by using a time-of-flight mass spectrometer, and 14N and 15N isotopically labelled species.181 

When C1207 reacted with NC13, primary and secondary amine compounds belonging to the class of perchloric acid amides were produced  

The remaining hydrogen atoms on N could be replaced by metal cations  

It was found that the nature of the N—Cl bond depended on the other substituents on the nitrogen.182 

Liquid-vapour equilibria in the systems formed by arsenic trichloride and its most probable impurities, i.e. SOaCl, SOCI2, PSCI3, and POCI3, have been studied, showing that the latter two are the most difficult to remove by simple distillation. Substituted halogenoarsines react in the presence of triethylamine with aldoximes to give the esters R As(ON CHR 2 and 

and Raman studies have shown the formation of complexes between tributyl phosphate and both arsenic and antimony tribromides. Cryoscopy in fused arsenic tribromide is reported for a num r of inorganic and organic solutes, showing dTj X values lower than the ideal value, and with dioxan the compound 2AsBr3,3dioxan, melting at 64 °C, is formed. Arsenic and antimony trihalides give a-bonded transition-metal derivatives, such as X2E[Fe(CO)2(Cp)]J, where E = As or Sb and X = Cl or Br, on reaction with metal carbonyl anions or metal carbonyls with metal-metal bonds.  

The Hammett acidity function has been evaluated for a number of superacid systems, including HSOgF-AsFs and HSOgF-SbEg. The structure of the AsgFjoO- ion in the dicaesium salt has been determined by X-ray 

Nisel son, K. V. Tret yakova, and V. Ya. Akhmadeev, Russ, J. Inorg. Chem., 

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A. G. MacDiarmid, Organometallic Compounds of the Group IV Elements, Vol. 2, The Bond to Halogens and Halogenoids, Marcel Dekker, Inc., New York, 1972. 

Because of the reactive covalent bonds to halogen atoms, all of the trihalides of the group VA elements hydrolyze in water. It is found that the rates decrease in the order P > As > Sb > Bi, which agrees with the decrease in covalent bond character that results from the increase in metallic character of the central atoms. Not all of the trihalides react in the same way. The phosphorus trihalides react according to the equation... 

In this section, you reviewed how to name and draw alkanes, alkenes, and alkynes. You also learned how to name aromatic hydrocarbons. The names of all the other organic compounds you will encounter in this unit are based on the names of hydrocarbons. In the next section, you will learn about organic compounds that have single bonds to halogen atoms, oxygen atoms, and nitrogen atoms. 

For a review of hydrogen bonding to halogens, see Smith, in Patai The Chemistry of the Carbon-Halogen Bond, pt. 1 Wilev New York. 1973. pp. 265-300. See also Bastiansen Femholt Hedberg Scip J Am. Chem. Soc. 1985, 107. 7836. ... 

Table 2 Some Representative Values for Average Bond Energies for Bonds to Halogens (kJmol-1, 298 K)...

Few bond energy data are available for lead (Table 1), and are rather subjective. They do, however, follow expected trends, for example, bonds to halogen are strongest with fluorine and decrease with increasing size of the halogen bonds to carbon, hydrogen, and lead are quite weak. 

Vol. 2 The Bond to Halogens and Halogenoids, Part 1 (1972). C. H. Van Dyke, Synthesis and properties of the silicon-halogen and silicon-halogenoid bond. 296 pp. (1248). 

The alternative interpretation is simple. In alkyl halides the carbon holding halogen is 5/ -hybridized. In aryl and vinyl halides, carbon is j/ 2-hybridized the bond to halogen is shorter and stronger, and the molecule is more stable (see Sec. 5.4). 

Bonds to Halogens.—Reactions between AsF3 and the negative ions formed mass spectrometrically lead to AsF ( as the predominant secondary ion, whereas in AsF5, both AsFj and AsF<( are formed.629 A series of new fluoroarsinic acid esters F As(OR)3 n, with n = l or 2 and R = methyl to hexyl, result from either alcoholysis of the trifluoride or redistribution reactions between mixtures of the trifluoride and trialkoxide.630 The product identities were confirmed by 19F and H n.m.r. spectroscopy. 

In the two structures just described the odd structural water molecule is linked to other water molecules and to an oxygen atom of the S04 groups. It is interesting to note, however, that halides rarely crystallize with an odd number of water molecules because hydrogen bonds to halogen atoms (except fluorine) are not, in general, formed and structural water cannot therefore be held in the crystal. 

Bonds to Halogens.—From new data on the heat of hydrolysis, the standard heat of formation of AsFj has been revised to -205.1 kcal moP (858.14 kJ moP ), giving... 

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