Search results
Results from the WOW.Com Content Network
Biphenyl is a solid at room temperature, with a melting point of 69.2 °C (156.6 °F). In the gas phase the molecule exists in two enantiomorphic twisted forms with an angle between the planes of the two rings of 44.4°. In the room-temperature solid, biphenyl is crystalline with space group P2 1 /c, which does not allow for chiral crystals.
Biphenylene was first synthesized by Lothrop in 1941. [12] The biphenylene structure can also be understood as a dimer of the reactive intermediate benzyne, which in fact serves as a major synthetic route, by heating the benzenediazonium-2-carboxylate zwitterion prepared from 2-aminobenzoic acid. [13]
Heteroarenes are aromatic compounds, where at least one methine or vinylene (-C= or -CH=CH-) group is replaced by a heteroatom: oxygen, nitrogen, or sulfur. [3] Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes a single oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one ...
Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as a placeholder for the aryl group in chemical structure diagrams, analogous to “R” used for any organic substituent. “Ar” is not to be confused with the elemental symbol for argon. A simple aryl group is phenyl (C 6 H 5 −), a group derived from benzene ...
Hückel's rule is not valid for many compounds containing more than one ring. For example, pyrene and trans-bicalicene contain 16 conjugated electrons (8 bonds), and coronene contains 24 conjugated electrons (12 bonds). Both of these polycyclic molecules are aromatic, even though they fail the 4n + 2 rule. Indeed, Hückel's rule can only be ...
PCBs share the basic chemical structure of biphenyl and one or more of the hydrogen atoms on the aromatic rings are replaced by chlorine atoms. [1] PCBs is in viscous liquid form at normal temperature and has a poor solubility in water. The aromatic hydrocarbon structure gives PCBs relatively high molecular stability.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Many or even most phenyl compounds are not described with the term "phenyl". For example, the chloro derivative C 6 H 5 Cl is normally called chlorobenzene, although it could be called phenyl chloride. In special (and rare) cases, isolated phenyl groups are detected: the phenyl anion (C 6 H − 5), the phenyl cation (C 6 H + 5), and the phenyl ...