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Equilibrium vaporization behaviour of twelve IIB/VIA‐compounds of the type MeX was studied by means of high‐temperature mass spectrometry. In all cases except HgTe the existence of stable MeX(g)‐molecules was established. Bond energies D0(MeXgas) were determined by the thermodynamic third‐law method and range as follows: ZnO(g) (280.1 kJ/mol)/ZnS(g) (224.8)/ZnSe(g) (170.8)/ZnTe(g) (117.7)/CdO(g) (230.3)/CdS(g) (208.5)/CdSe(g) (127.7)/CdTe(g) (100.1)/HgO(g) (221.1)/HgS(g) (217.3)/HgSe(g) (144.5). ‐ Comparison of the third‐law bond energies with existing experimental data, upper limits of D0 given by other authors, and semi‐empirical estimates shows basic agreement. Data for the heat of dissociative vaporization ΔH0R, the heat of atomization ΔH0at, the parameter , and the chemical stabilities of the IIB/VIA‐systems are also presented.

Ionization efficiency curves of the gaseous sulfur species Si (i = 2–8) in equilibrium with solid red HgS were obtained by electron impact ionization. Analysis of fine structure of the curves yields energy levels of ground and excited ion states. — For S2 and S8 the experimental values are in good agreement with independent photoionization and photoelectron spectroscopic data from the literature. In the case of S3 to S7 numerous appearance potentials were determined which reflect processes such as direct ionization, autoionization, fragmentation, and predissociation. Extended Hückel calculations were performed for verification of the experimental energies and for spectroscopic assignment of states. — By the second and third law methods the heats of the gas phase reactions Si(g) = i/2 S2(g) (i = 3–8) and average bond energies of the sulfur species were determined.

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We h~ve measured the ionization potentials of gaseous ferrocene and the symmetrically ~ub~tlt~ted chlor~fe?"ocenes, F~( CsHs _ NCI N h (O..;;N";;5) by electron impact techniques. The lOntzatlOn potentIal IS found to mcrease in direct proportion to the number of chlorine substit~tions. !hese results indicate that chlorine ring substitutions result in greater overlap of the 11"-nng orbItals and the metal d orbitals. The binding energies of the unoccupied orbitals of ferrocene and 1,I'-dichloroferrocene have been inferred from photoabsorption studies. The effect of symmetric dichlorination on the splitting of the unoccupied 5e l ferrocene molecular orbital is described. g