The Arrangement of atoms in spaceLongmans, Green and Company, 1898 - 211 páginas |
Términos y frases comunes
according alcohol ammonia ammonium amyl arabinose Arabonic asymmetric carbon atom benzene borneol cent change of rotation Chem Chim chloride Cinchonine cinnamic acid CO,H CO₂H CO₂H CO₂H H Compt configuration corresponding derivatives dilution division double enantiomorphous fact Fischer formula fumaric acid fumaric and maleïc Gluconic acid glucose groups attached Guye H CO₂H H H H H,COH H₂COH Hantzsch HCOH HCOH HCOH HCOH HOCH HOCH HCOH HOCH HOCH HOCH Hoff hypothesis ibid identical isomerism isomers isomers of opposite lactic acid lactone Ladenburg left-handed lyxose malic acid mannite mannose methyl mixture molecular molecule mucic acid nitrogen observed obtained opposite activity Pasteur physik platosammine R₁ C R₂ racemic acid radical Rend Ribonic acid right-handed ring formation Saccharic acid salts Solubility solution Sorbite stereochemical stereochemistry substances symmetry tartaric acid tartrates temperature tetrahedron tion Trans transformation Walden Wislicenus xylose Zeitschr нсон он осн
Pasajes populares
Página ix - ... with the exception that the asymmetry is shown in opposite senses. Are the atoms of the dextro acid arranged in the form of a right-handed spiral, or are they situated at the corners of an irregular tetrahedron, or do they have some other asymmetric grouping? This we do not know. But without doubt the atoms possess an asymmetric arrangement like that of an object and its reflected image.
Página 142 - B + c - c + c + c and since the sum of No. 2, No. 3, and No. 4 is equal to A + B •{• C, the rotation of arabinose (probably the highest) should be equal to the rotations of xylose, ribose, and the expected fourth type - taken together.
Página vi - ... double refraction, all these things are not merely alike, similar, nearly allied, but identical in the strictest sense of the word." The only difference is due to the lack of symmetry, and this is m anifested : (i) Physically. Opposite optical activity, the so-called rightand left-handed rotation, is shown by the isomers in the dissolved state — in the state, that is, when the rotation must arise from molecular, not from crystalline structure. (ii) Crystallographically. Isomers due to asymmetric...
Página i - I choose this fundamental conception as the starting point for this reason, that there is alre.idy evident in the rough outlines of this future system of atom mechanics a very considerable simplification, which I will here discuss. One might suppose that the arrangement of the atoms in the molecule would be something like that in a system of planets, equilibrium being maintained by attraction and motion, by equality between centripetal and centrifugal force.
Página 177 - MA6 ; the most simple hypothesis that can be formulated is an octahedral arrangement ; the metallic atom occupying the centre of the octahedron, the six groups A will have their places at the corners. It is evident that this arrangement should give rise to certain cases of stereomerism, of which we shall consider at present only one, which experiment confirms.
Página iii - ... round the carbon atom, only a tetrahedral grouping brings us to the same conclusion [as is shown by the figures below], The four groups combined with the carbon atom are placed at the corners of a tetrahedron. Hence no isomers unless all four groups are different. which become identical when R3 and R4 become the same, while this leaves the isomerism unaffected if we represent the formulae in one plane [thus] :