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2. Baird's rule - Wikipedia

   en.wikipedia.org/wiki/Baird's_rule

   In organic chemistry, Baird's rule estimates whether the lowest triplet state of planar, cyclic structures will have aromatic properties or not. The quantum mechanical basis for its formulation was first worked out by physical chemist N. Colin Baird at the University of Western Ontario in 1972.

3. Antiaromaticity - Wikipedia

   en.wikipedia.org/wiki/Antiaromaticity

   Nucleus Independent Chemical Shift (NICS) analysis is a method of computing the ring shielding (or deshielding) at the center of a ring system to predict aromaticity or antiaromaticity. A negative NICS value is indicative of aromaticity and a positive value is indicative of antiaromaticity. [9]

4. Aromatic ring current - Wikipedia

   en.wikipedia.org/wiki/Aromatic_ring_current

   In this method, negative NICS values indicate aromaticity, and positive values indicate antiaromaticity. [6] [7] There are a variety of methods to calculate NICS values, however, the most robust method for calculating NICS values involves scanning the molecule in a NICSzz scan. In this process, the NICS value is calculated above the rings, and ...

5. Clar's rule - Wikipedia

   en.wikipedia.org/wiki/Clar's_rule

   Clar's rule has also been supported by experimental results about the distribution of π-electrons in polycyclic aromatic hydrocarbons, [7] valence bond calculations, [8] and nucleus-independent chemical shift studies. [9] Clar's rule is widely applied in the fields of chemistry and materials science.

6. Thermodynamic activity - Wikipedia

   en.wikipedia.org/wiki/Thermodynamic_activity

   The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.

7. Möbius aromaticity - Wikipedia

   en.wikipedia.org/wiki/Möbius_aromaticity

   In organic chemistry, Möbius aromaticity is a special type of aromaticity believed to exist in a number of organic molecules. [ 1 ] [ 2 ] In terms of molecular orbital theory these compounds have in common a monocyclic array of molecular orbitals in which there is an odd number of out-of-phase overlaps, the opposite pattern compared to the ...

8. Bredt's rule - Wikipedia

   en.wikipedia.org/wiki/Bredt's_rule

   In organic chemistry, an anti-Bredt molecule is a bridged molecule with a double bond at the bridgehead. Bredt's rule is the empirical observation that such molecules only form in large ring systems. For example, two of the following norbornene isomers violate Bredt's rule, and are too unstable to prepare: Bridgehead atoms violating Bredt's ...

9. Wikipedia : Manual of Style/Chemistry/Structure drawing

   en.wikipedia.org/.../Chemistry/Structure_drawing

   Chemical structures and reaction schemes should conform to the following: Images should be drawn with a molecule editor, never freehand; ACS settings should be used for both structures and reaction schemes. These settings are normally available as templates in chemical drawing programs. Use sans-serif fonts like Arial.