Hydrogen fluoride molecule

However, many substances, notably alcohols, have a greater proton affinity than the hydrogen fluoride molecule, and so behave as bases, for example ethanol ... 

The experimental bond length for the hydrogen fluoride molecule is 0.917A. Determine the basis set required to predict this structure accurately. Perform your optimizations at the MP4 level of theory (electron correlation is known to be important for this system). 

Difluorine is an extremely active reagent and reacts with organic molecules at low (200 and lower) temperatures. Such a high activity of difluorine is due to the very high BDE of the formed hydrogen fluoride molecule (-DF H = 570 kJ mol ) and the relatively low BDE in the difluorine molecule (DF F = 158.7 kJ mol-1). Due to this great difference in the BDE of the reactants and the products, bimolecular reactions of hydrogen atom abstraction... 

The fluorination of 2,5-dihydroxybenzo-l,4-quinone and 2-hydroxynaphtho-l,4-quinone results, as well as replacement of the carbonyl oxygen atoms by fluorines, in replacement of the hydroxy groups and addition of a hydrogen fluoride molecule across a C = C bond to give,... 

Fig. 4.4 shows a representation of the hydrogen fluoride molecule as a dipole. The dipole moment is represented as an arrow, marking the positive end. Since the dipole moment... 

Heteronuclear diatomic molecules (1) The hydrogen fluoride molecule... 

The effect of an electric field on hydrogen fluoride molecules, (a) When no electric field is present, the molecules are randomly oriented. (b) When the field is turned on, the molecules tend to line up with their negative ends toward the positive pole and their positive ends toward the negative pole. (This illustration exaggerates the effect. Actually, only a small fraction of the molecules are lined up with the field at a given instant.)... 

Show how a hydrogen Is atomic orbital and a fluorine 2p atomic orbital overlap to form bonding and antibonding MOs in the hydrogen fluoride molecule. Are they cr or 77 MOs ... 

In this molecule, the hydrogen fluoride molecule, there is a single covalent bond (shared-electron-pair bond), which holds the hydrogen atom and the fluorine atom firmly together. The distance between the nuclei of these two atoms is 0.92A, according to experimental determination made by the study of the spectrum of the gas. 

Consider, as a first example, the hydrogen fluoride molecule (Fig. 39). 

In discussing bonds involving hybrid AO s it is necessary to introduce atomic valence states. If the above description (p. 96) is accepted, the energy of the hydrogen fluoride molecule can be discussed. The bond is... 

Figure 29.3. The hydrogen fluoride molecule dependence of overlap on orbital symmetry, a) Overlap of lobes of same phase leads to bonding. b) Positive overlap and negative overlap cancel each other.

Note that the fluoride ion acts as a Brpnsted-Lowry base and accepts a hydrogen ion from H2O. Hydrogen fluoride molecules and OH ions are produced. Although the resulting equilibrium lies far to the left, the potassium fluoride solution is basic because some OH ions were produced... 

The hydrogen fluoride molecule may be used as a simple example of this approach. Using the 6-31G basis the PA charge on F is -0.395 e. This monopole value yields, when combined with the bond distance of 1.733 au, a dipole moment of 0.685. However, the exact operator dipole obtained from the wavefunction is 0.776. In the cumulative procedure, the difference between these two values is made up with atomic dipoles. From [13] one obtains (w)f = + 0.330 and [w] = +0.446, which of course sum to the exact molecular dipole. Application of Eq. [14] yields cumulative atomic dipoles Mj. = -0.012 and Mh = 0.103. The sum of the PA charge dipole plus the atomic dipoles equals the exact molecular dipole. Analogous procedures are used for higher moments. 

Fig. 3. Relative gain of vibrational-rotational transitions in the hydrogen fluoride molecule for Trot = 300° K and various population ratios -We-z/lV -1. It is seen that the gain is always lower in the R-branch than in the corresponding P-branch transitions... 

P. Politzer and R. S. Mulliken, J. Chem. Phys., 55,5135 (1971). Comparison of Two Atomic Charge Definitions, as Applied to the Hydrogen Fluoride Molecule. 

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