Microwave Spectra and Structures of Methyl Mercury Chloride and Bromide

Abstract

From the pure rotational spectra of several different isotopic species of CH₃HgCl it is shown that d_CHg=2.061±0.02A, d_HgCl=2.282±0.005A, and ∠CHgCl=180°. Similarly, for CH₃HgBr it is shown that d_CHg=2.074±0.015A, d_HgBr=2.406±0.005A, and ∠CHgBr=180°. Nuclear quadrupole couplings evaluated are Cl³⁵=—42 Mc, Cl³⁷=—33 Mc in CH₃HgCl, and Br⁷⁹=350 Mc, Br⁸¹=290 Mc in CH₃HgBr. These indicate ionic character of 62 percent for the HgCl and 55 percent for the HgBr bond in these molecules, and lead to a value of 1.7 to 1.8 for the electronegativity of divalent mercury.