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  • Baeyer strain theory
  • Incorrect nineteenth-century theory that considered the rings of cycloalkanes to be planar and assessed their stabilities according to how much the angles of a corresponding regular polygon deviated from the tetrahedral value of 109.5
  • Baeyer-Villiger oxidation
  • Oxidation of an aldehyde or, more commonly, a ketone with a peroxy acid. The product of Baeyer-Villiger oxidation of a ketone is an ester.  FIG
  • Ball-and-stick Model
  • Type of molecular model in which balls representing atoms are connected by sticks representing bonds. Also called ball-and-spoke models.
  • Base
  • According to the Arrhenius definition, a substance that ionizes in water to produce hydroxide ions. According to the BrĂ˜nsted-Lowry definition, a substance that accepts a proton from some suitable donor. According to the Lewis definition, an election-pair donor.
  • Base Pair
  • term given to the purine of a nucleotide and its complementary pyrimidine. Adenine (A) is complementary to thymine (T), and guanine (G) is complementary to cytosine (C).
  • Base Peak
  • The most intense peak in a mass spectrum. The base peak is assigned a relative intensity of 100, and the intensities of all other peaks are cited as a percentage of the base peak.
  • Basicity Constant Kb
  • A measure of base strength, especially of ammines.  EQAUTION
  • Bending Vibration
  • The regular, repetitive motion of an atom or a group along an arc the radius of which is the bond connecting the atom or group to the rest of the molecule. Bending vibrations are one type of molecular motion that gives rise to a peak in the infrared spectrum.
  • Benzyl group
  • the group C6H5CH2-
  • Benzylic carbon
  • A carbon directly attached to a benzene ring. A hydrogen attached to a benzylic carbon is a benzylic hydrogen. A carbocation in which the benzylic carbon is positively charged is a benzylic carbocation. A free radical in which the benzylic carbon bears the unpaired electron is a benzylic radical.

  • Benzyne
  • Benzene that lacks two hydrogens.  FIG
  • Bile acids
  • Steroid derivatives biosynthesized in the liver that aid digestion by emulsifying fats
  • Bimolecular
  • A process in which two particles react in the same elementary step.
  • Bioenergetics
  • The study of energy transfer in biological processes
  • Biological isoprene unit
  • Isopentenyl diphosphate, the biological precursor to terpenes and steroids.  FIG
  • Birch reduction
  • Reduction of an aromatic ring to a 1,4-cyclohexadiene on treatment with a group 1 metal (Li, Na, K) and an alcohol in liquid ammonia.
  • Block copolymer
  • A copolymer of monomers A and B in which sections of poly-A and poly-B of variable length alternate.
  • Boat conformation
  • An unstable conformation of cyclohexane.  FIG
  • Bond dipole moment
  • The dipole moment of a bond between two atoms
  • Bond dissociation enthalpy
  • For a substance A:B, the energy required to break the bond between A and B so that each retains one of the electrons in the bond
  • Bond-Length distortion
  • The deviation of the length of a bond between two atoms from its normal value.
  • Bond-Line formula
  • Formula in which connections between carbons are shown but individual carbons and hydrogens are not. FIG ex 2-methylbutane
  • Bonding orbital
  • An orbital in a molecule in which an electron is more stable than when localized on an isolated atom. All the bonding orbitals are normally double occupied in stable neutral molecules
  • Boundary surface
  • The surface that encloses the region where the probability of finding an electron is high (90-95%).
  • Branched polymer
  • A polymer with branches having the same repeating units as the main chain
  • Branched-Chain carbohydrate
  • Carbohydrate in which the main carbon chain bears a carbon substituent in place of a hydrogen or hydroxyl group
  • Brønsted acid
  • See Acid link
  • Brønsted base
  • See Base LINK
  • Bridged compound
  • A compound in which two nonadjacent atoms are common to two or more rings
  • Broadband decoupling
  • A technique in 13C NMR spectroscopy that removes the splitting of 13C signals caused by coupling of 13C and 1H nuclei. Thus, all of the 13C signals appear as singlets
Department of Chemistry & Chemical Biology