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  2. Double bond - Wikipedia

    en.wikipedia.org/wiki/Double_bond

    In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist between two different elements: for example, in a carbonyl group between a carbon atom and an oxygen atom.

  3. Carbon–carbon bond - Wikipedia

    en.wikipedia.org/wiki/Carboncarbon_bond

    A carboncarbon bond is a covalent bond between two carbon atoms. [1] The most common form is the single bond: a bond composed of two electrons, one from each of the two atoms. The carboncarbon single bond is a sigma bond and is formed between one hybridized orbital from each of the carbon atoms. In ethane, the orbitals are sp 3 ...

  4. Double bond rule - Wikipedia

    en.wikipedia.org/wiki/Double_bond_rule

    Double bond rule. In chemistry, the double bond rule states that elements with a principal quantum number (n) greater than 2 for their valence electrons (period 3 elements and higher) tend not to form multiple bonds (e.g. double bonds and triple bonds). Double bonds for these heavier elements, when they exist, are often weak due to poor orbital ...

  5. Linnett double-quartet theory - Wikipedia

    en.wikipedia.org/wiki/Linnett_Double-Quartet_Theory

    Right: Simplified diagram of the LDQ structure of O 3, showing electrons in non-coincident pairs using thin lines and a coincident electron pair using a thick line. Linnett double-quartet theory (LDQ) is a method of describing the bonding in molecules which involves separating the electrons depending on their spin, placing them into separate ...

  6. Bond order - Wikipedia

    en.wikipedia.org/wiki/Bond_order

    The bond order between carbon and oxygen in carbon dioxide O=C=O is also 2. In phosgene O=CCl 2, the bond order between carbon and oxygen is 2, and between carbon and chlorine is 1. In some molecules, bond orders can be 4 (quadruple bond), 5 (quintuple bond) or even 6 (sextuple bond). For example, potassium octachlorodimolybdate salt (K 4 [Mo 2 ...

  7. Alkene - Wikipedia

    en.wikipedia.org/wiki/Alkene

    Alkene. In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carboncarbon double bond. [1] The double bond may be internal or in the terminal position. Terminal alkenes are also known as α-olefins. The International Union of Pure and Applied Chemistry (IUPAC) recommends using the name "alkene" only for acyclic ...

  8. Cahn–Ingold–Prelog priority rules - Wikipedia

    en.wikipedia.org/wiki/Cahn–Ingold–Prelog...

    For double bonded molecules, Cahn–Ingold–Prelog priority rules (CIP rules) are followed to determine the priority of substituents of the double bond. If both of the high priority groups are on the same side of the double bond (cis configuration), then the stereoisomer is assigned the configuration Z (zusammen, German word meaning "together").

  9. Bredt's rule - Wikipedia

    en.wikipedia.org/wiki/Bredt's_rule

    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 enough ring systems. For example, two of the following norbornene isomers violate Bredt's rule, and are too unstable to prepare: The rule is named ...