Halogen triatomic

N2, etc., at low temperatures. That of the halogens is greater, and Boltzmann supposed the connexion between the atoms was loosened with rise of temperature. Triatomic gases have the 6R... 

The triatomic cations are usually prepared from the corresponding interhalogen, by reaction with a halogen acceptor molecule. This is impossible for some of the more exotic species which have no interhalogen precursor. For example, the [Br3]+ cation has been characterized20 in [Br3]+[AsF6], formed from the interaction of arsenic pentafluoride and a bromine/bromine pentafluoride mixture and the [Cl FJ cation results from the interaction of antimony pentafluoride with chlorine monofluoride.21... 

Vibrational Frequencies and Force Constants for the Triatomic Halogen Cations... 

The reactions44-45 of alkali dimers with halogen molecules offer an opportunity to study the dynamics of four-centre reactions. Three-centre reactions of an atom plus diatomic molecule have been extensively studied and also four-centre reactions46 of an atom plus triatomic molecule. However, there are few examples known47 of reactive four-centre diatomic plus diatomic systems. 

Fig. 22. Schematic diagram of molecular orbitals in the linear configuration for triatomic reaction complexes H + XY, CH3 + XY and Y + XY, where X, Y denote halogen atoms (from C. F. Carter et al.102 by permission of the Chemical...

This section briefly considers the proton H , the hydride ion H , the hydrogen molecule ion H2", the triatomic 2-electron species H3+ and the recently established cluster species The hydrogen atom has a high ionization energy (1312kJmol ) and in this it resembles the halogens rather than the alkali metals. Removal of the Is electron leaves a bare proton which, having a radius of only about 1.5 x 10 pm, is not a stable chemical entity in the condensed phase. However, when bonded to other species it is well known in solution and in... 

Table 2.2c lists the vibrational frequencies of triatomic halogeno compounds. The resonance Raman spectrum of the I3 ion gives a series of overtones of the Vi vibration [408,409]. The resonance Raman spectra of the l2Br and IBr2 ions and their complexes with amylose have been studied [410]. The same table also lists the vibrational frequencies of XHY-type (X,Y halogens) compounds. All these species are linear except the ClHCl ion, which was found to be bent by an inelastic neutron scattering (INS) and Raman spectral study [402]. 

The DMC method is compared with a variational method within a vibrational diabatic approximation (VDA) applied to the halogen vibrational motion for both the triatomic and the tetraatomic complex. Hereafter we shall call this procedure diabatic DMC (DDMC). 

These reactions are certairily, like the triatomic alkali-halogen systems (e.g, K + Br2), initiated by an electron jump ( harpooning ) ... 

The strong coupling shown above takes place because the individual vibrators are identical. The less similar they are in terms of frequency, the lower will be the degree of coupling. This is revealed by consideration of the frequencies of simple triatomic linear cyanide molecules shown in Table 2. For HCN and the halogenides, the natural (isolated) C-H or C-halogen frequencies are very different from v(C=N) and there is little interaction, as demonstrated by the roughly constant values of the latter. But this is not so for DCN and TCN (T = tritium), where by extrapolation from v(C-H) the C-D and C-T oscillators would have natural frequencies of about 2430 and 2050 cm" respectively. 

The potential energy surfaces of triatomic hydrides XH2, where X is a halogen atom, are of considerable interest in theoretical investigations of the abstraction and exchange reactions... 

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