New Raman data for solutions, powders, and oriented single crystals are reported which allow a consistent assignment of the vibrational spectra of the title compounds. The four Raman-active v(C0) modes for Mn2(CO)lo are at 21 16(al), 2024(e,), 1 997(a,), and 1981 (e3) cm-l. Low-frequency spectra of considerably improved quality are also presented. All of the a, bands have been located for Re,(CO),,and all but one for Mn,(CO),,for solutions. LE1 7RHDESPITE the considerable effort expended upon the spectra of Mn2(CO)lo1-14 and, to a lesser extent, Re,-(CO)10,1-3,7J1-16 anomalies remain both in the data and the assignments for these molecules, even in the carbonyl stretching region. We report new experimental evidence which leads to a reassignment for both molecules.

Vibrational spectra of a series of halogeno-complex ions of antimony(III) and bismuth(III) are reported. Results of crystal spectra are discussed in terms of the structural environment and a comparative study of Raman solution and solid state spectra is given. Some force constants for hexahalogeno species on a modified Urey-Bradley force field have been calculated and their significance is discussed.

The v~brational spectra of crystalline halomercurate salts with anionic stoicheiometries HgX3-, HgX42-, Hg2X6-, HgsXs2-(where X = C1, Br, I) have been studied. The cations Me&+, Et4N+, Ph&+, and pyH+ were used as necessary. The effect of crystalline symmetry and packing on the spectra of both anion and cation are discussed and the spectra are used to deduce the most probable crystalline packmg for salts contamng the HgzXs-and Hg3Xs2-specles. The spectra of the cations 3Ie&S+ and Et4S+ are assigned and d~scussed.

The generalized van der Waals theory is here extended by incorporating the hard-sphere diameter as a variational parameter. Moreover, the entropy functional has been chosen so as to accurately reflect the density dependence of the excluded volume revealed by the hard-sphere equation of state. The combined effect of these two improvements yields a theory capable of describing the equation of state of the Lennard-Jones model of classical fluids to an accuracy comparable to that of the pair correlation theories. The results presented here include critical parameters and coexistence and vapour pressure curves.

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