Structural Chemistry of Organomercury Compounds. Role of Secondary Interactions

The structures of the organomercury compounds have been reviewed from the point of view of the secondary bonds which mercury atom forms with the surrounding atoms. These bonds, though rather labile, exhibit a definite influence on the crystal structure which is manifested in a peculiar coordination around the mercury atom. This influence has to be studied systematically since the mercury coordination polyhedra in the crystal structure of organomercury compounds are far from being regular. The review has been restricted to the structures in which the secondary bonds of mercury are shorter than the sum of the van der Waals radii. The upper limit of the distances within the coordination polyhedron cannot be well substantiated while the distances larger than the sum of the van der Waals radii may be also influencial in the structure. The influence of the long-range contacts, both on the molecular structure as a whole as well as on the stability of the secondary bonds, may be quite essential. The long-range contacts actually reproduce the solvation effect in chemical reactions in solutions. From this point of view the X-ray diffraction data are useful for the study of the chemical reaction mechanism in the organic chemistry of mercury

Fluctuations of Xmax and Primary Particle Mass Composition in the Range of Energy 5 10^{17} - 3 10^{19} ev by Yakutsk Data

The experimental distributions of \Xmax obtained with the Yakutsk EAS array at fixed energies of $5 \times10^{17}$, $1\times10^{18}$ and $5\times10^{18}$ eV are analysed. A recent version of the QGSJET model is used as a tool of our analysis. In the framework of this model, the most adequate mass composition of primary particles satisfying the experimental data on \Xmax is selected.Comment: 19th European Cosmic Ray Symposium, Aug 30 - Sep 3 2004, Florence, Italy. 3 pages, 1 figure. Submitted for publication in International Journal of Modern Physics

\u3cem\u3eβ\u3c/em\u3e-Homopipitzolone

The structure of β-homopipitzolone (one of the two isomers of an intermediate product in the homocedrole synthesis) has been unequivocally established as 1 O-hydroxy-2,6,9-trimetbyltricyclo[6.3.1.01,6] dodeca-9-ene-5, II, 12-trione with relative IR,2R,6R,8S configuration

Structural Chemistry of Organomercury Compounds. Role of Secondary Interactions

The structures of the organomercury compounds have been reviewed from the point of view of the secondary bonds which mercury atom forms with the surrounding atoms. These bonds, though rather labile, exhibit a definite influence on the crystal structure which is manifested in a peculiar coordination around the mercury atom. This influence has to be studied systematically since the mercury coordination polyhedra in the crystal structure of organomercury compounds are far from being regular. The review has been restricted to the structures in which the secondary bonds of mercury are shorter than the sum of the van der Waals radii. The upper limit of the distances within the coordination polyhedron cannot be well substantiated while the distances larger than the sum of the van der Waals radii may be also influencial in the structure. The influence of the long-range contacts, both on the molecular structure as a whole as well as on the stability of the secondary bonds, may be quite essential. The long-range contacts actually reproduce the solvation effect in chemical reactions in solutions. From this point of view the X-ray diffraction data are useful for the study of the chemical reaction mechanism in the organic chemistry of mercury