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In chemistry, the Fischer projection, devised by Emil Fischer in 1891, is a two-dimensional representation of a three-dimensional organic molecule by projection. Fischer projections were originally proposed for the depiction of carbohydrates and used by chemists, particularly in organic chemistry and biochemistry. The use of Fischer projections ...
A space-filling model of n-octane, the straight chain (normal) hydrocarbon composed of 8 carbons and 18 hydrogens, formulae: CH 3 CH 2 (CH 2) 4 CH 2 CH 3 or C 8 H 18.Note, the representative shown is of a single conformational "pose" of a population of molecules, which, because of low Gibbs energy barriers to rotation about its carbon-carbon bonds (giving the carbon "chain" great flexibility ...
This type of representation clearly illustrates the specific dihedral angle between the proximal and distal atoms. [ 2 ] This projection is named after American chemist Melvin Spencer Newman , who introduced it in 1952 as a partial replacement for Fischer projections , which are unable to represent conformations and thus conformers properly.
Organic chemistry and especially biochemistry are the areas of chemistry that use the Haworth projection the most. The Haworth projection was named after the British chemist Sir Norman Haworth. [2] A Haworth projection has the following characteristics: [3] Carbon is the implicit type of atom. In the example on the right, the atoms numbered ...
Spacefilling models or CPK models (also an atomic coloring scheme in representations) – the molecule is represented by overlapping spheres representing the atoms. Cartoon – a representation used for proteins where loops, beta sheets, and alpha helices are represented diagrammatically and no atoms or bonds are explicitly represented (e.g ...
"Molecular Models - Tangible Representations of the Abstract". PDB Newsletter. 41: 4– 5. history of molecular models Paper presented at the EuroScience Open Forum (ESOF), Stockholm on August 25, 2004, W. Gerhard Pohl, Austrian Chemical Society. Photo of van't Hoff's tetrahedral models, and Loschmidt's organic formulae (only 2-dimensional).
In chemistry, the ball-and-stick model is a molecular model of a chemical substance which displays both the three-dimensional position of the atoms and the bonds between them. [1] The atoms are typically represented by spheres , connected by rods which represent the bonds.
Saccharide and other chemical conformations can be reasonably shown using two-dimensional structure representations that follow set conventions; these capture for a trained viewer an understanding of the three-dimensional structure via structure drawings (see organic chemistry article, and "3D Representations" section in molecular geometry ...