Organic chemistry

1890 Journal of the Chemical Society Abstracts  
O r g a n i c C h e m i s t r y . Results and Aims of Stereochemical Research. By V. MEYER (Ber., 23, 567--619).-The author first gives an historical review of the development of stereocheniical or space formulae. Although i t w a ,~ long tacitly understood that the four hydrogen-atoms in methane must be arranged symmetrically in space around the carbonatom, Van't Huff and Le Be1 were the first to point out the important advantages that are derivcd by the adoption of the tetrahedral symbol for
more » ... ahedral symbol for the carbon-atom to which the above view nntumlly leads. By this method they were able to explain the isomerism of a number of compounds, such as the lactic acids, the formulae of which contain asymmetrical carbon-at,oms, and therefore in space are ca.pable of two enantiornorphic methods of representation. Geometrical isomerism ie then possible amongst substances containing an asymmetrical carbonatom, and i t was likewise shown t,hat such geometrical isomerides frequently show optical activity. A distinct connection was tracecl View Article Online that t h e valcncies of carbon are directed towards the solid angles of a regular tetrahedron, and calling the six planes of symmetry which characterise the compouiid CR, the planes of c u~b o n symnzetry, i t is evident that so long as the carbon remains synimetrical the centre of gravity of the molecule will be found in one, a t least, of these planes. On tile other hand, if the carbon becomes asymmetrical, the centre of gravity will be outside these planes. I n the first case, the product of asymmetry, t h a t is, the product of the distances of the centre of gravity of the molecule from eacli o€ the planes of symmetry, will be zero ; in the second case, it will have a definite value. If the signs + andare given to these distances, measured from one side or the other of each plano of
doi:10.1039/ca8905800719 fatcat:d4v6i6yikrer7esszkxybr34pa