Chemistry Glossary Terms Starting with the Letter B

Chemistry Glossary and Dictionary

Boiling involves the transition from the liquid to the gas phase.
Boiling involves the transition from the liquid to the gas phase. Markus Schweiss

This chemistry glossary offers definitions for terms which are commonly used in chemistry and chemical engineering. These chemistry words begin with the letter B.


β-branching - Beta branching is when a substituent is attached at a beta carbon. Beta branching is denoted as β-branching.

β-carbon - The beta carbon is the carbon atom one bond removed from the α-carbon in a molecule away from the moiety of interest.

 β-carbon is the most common notation of the beta carbon.

β-hydrogen - A beta hydrogen is a hydrogen atom bonded to the β-carbon of a molecule. β-hydrogen is the most common notation for beta hydrogen.

β-hydroxy acid - A beta-hydroxy acid is an acid containing a hydroxyl group attached to a β-carbon after the carboxyl group. Beta-hydroxy acid is also written as β-hydroxy acid or BHA.

background noise - Background noise is the sum of all noise or interference in a measurement which is independent of the data signal.
Also Known As: noise, interference

background radiation

back titration

bactericide - A bactericide is a substance that kills bacteria.
Also Known As: bacteriocide

Baeyer reagent - Baeyer reagent is dilute cold potassium permanganate solution, used to oxidize alkenes and alkynes.

bainite - Bainite is a Fe-C composition which consists of a fine dispersion of cementite in alpha-ferrite. Bainite is an austenitic transformation product that forms at temperatures between those at which the pearlite and martensite transformations occur.

balanced equation

Balmer series

band gap energy - The band gap energy is the span of energies that lie between the valence and conduction bands for insulators and semiconductors.

bar - A bar is a unit of pressure that is defined to be equal to 105 pascals. 1 bar = 105 Pascals = 1.01325 atmospheres = 14.5038 psi (pounds per square inch) = 29.53 in Hg (inches of mercury).



barrel - A barrel is a unit of volume. The volume of a barrel varies according to the industry.
For the petroleum industry: 1 barrel = 42 US gallons = 159 liters
Beer industry: 1 barrel = 31 US gallons = 117 liters
Dry goods: 1 barrel = 7,056 cubic inches = 115.6 liters.


base anhydride

base catalysis - Base catalysis is a chemical reaction that requires the presence of a base to act as a catalyst to proceed.

base dissociation constant (Kb) - The base dissociation constant is the equilibrium constant that measures the extent of dissociation for a base.
Example: The Base Dissociation Constant (Kb) for a base BOH is denoted by:
Kb = [B+]·[OH-] / [BOH]

base promoted - Base promoted refers to a chemical reaction that needs a base to proceed, but does not act as a catalyst for the reaction. Reactions needing a base and act as catalysts are called base catalysis reactions.

base metal


basic anhydride

basic solution

batch reactor - A batch reactor is a reactor which is characterized by its operation. In the case of a batch reactor, this means the reactor reaches steady state.

battery - A battery is a series of electrochemical cells using redox reactions to provide a source of electric current.

battery acid - Battery acid is any acid that can be used in a chemical cell or battery. The common use of the term battery acid refers to the acids used in lead-acid batteries for motor vehicles. Automotive battery acid is 30-50% sulfuric acid (H2SO4) with water. The acid typically has a mole fraction of 29-32%, concentration of 4.2-5.0 mol/L, density of 1.25-1.28 kg/L and a pH of approximately 0.8.

BCC - Body centered cubic or BCC refers to a crystal structure in which atoms are located at the corners of a cubic cell with one atom at the cell center position.

becquerel - The becquerel is a SI unit of radioactive activity. 1 becquerel = 1 radioactive decay/second (occasionally called 1 disintegration/second).

Beer-Lambert law

Beer's law

benzenoid ring - A benzenoid ring is an aromatic ring that possesses a benzene-like structure.

benzyl group - The benzyl group is the C6H5CH2 group, a type of organic chemical group.

benzyne - In organic chemistry: an unstable intermediate species consisting of a benzene ring with an adjacent chemical bond created by the side-to-side overlap of the sp2 orbitals on the adjacent carbon atoms of the ring.



beta branching - Beta branching is when a substituent is attached at a beta carbon. Beta branching is also denoted as β-branching.

beta carbon - The beta carbon is the carbon atom one bond removed from the α-carbon in a molecule away from the moiety of interest. β-carbon is the most common notation of the beta carbon.

beta decay

beta hydrogen - A beta hydrogen is a hydrogen atom bonded to the β-carbon of a molecule. β-hydrogen is the most common notation for beta hydrogen.

beta-hydroxy acid - A beta-hydroxy acid is an acid containing a hydroxyl group attached to a β-carbon after the carboxyl group.

beta particle

beta radiation

bidentate - Bidentate refers to a coordination complex where two ligands can attach itself to a central atom.
Also Known As: didentate
Example: Ethylenediamine is a bidentate ligand. The ligand can attach to a central atom at either of the unpaired electrons on the nitrogen atoms.

bidentate ligand - A bidentate ligand is an atom, ion, or molecule that can attach twice to a metal ion.

bifunctional monomer - A bifunctional monomer is a monomer unit with two active bonding positions.

bimolecular - Bimolecular refers to an elementary chemical reaction that occurs when two reactant molecules collide with each other.

binary acid

binary compound

binding energy

biochemistry - Biochemistry is the chemistry of living things. It is concerned with the structure and chemical processes of proteins, carbohydrates, lipids, nucleic acids and other molecules found in or produced by organisms.

biocide - A biocide is a substance or microorganism that kills or controls growth of living organisms.
Examples: Antibiotics, pesticides and antibacterials are all types of biocides.

biology - Biology is the scientific study of life. Biology involves the study of living organisms and how they relate to their environment. Fields of biology include botany, zoology, microbiology, biochemistry, genetics, molecular biology, cellular biology, physiology, and ecology.

bioorganic chemistry - Bioorganic chemistry is a chemistry discipline which integrates biochemistry and organic chemistry. Bioorganic chemistry involves the study of biological processes using chemical methods. Organic chemistry methods are used to synthesize biological molecules and to examine their structure and the kinetics of biochemical reactions.

bismuth - Bismuth is the name for the element with atomic number 83 and is represented by the symbol Bi. It is a member of the metal group.


black body - A black body is an idealized material that absorbs all incident electromagnetic radiation. Black bodies emit electromagnetic radiation determined by the temperature of the material regardless of shape or size according to Planck's law. Antonym: white body
Alternate Spelling: blackbody

black body radiation - Black body radiation refers to the electromagnetic radiation given off by a black body at thermal equilibrium. As the temperature increases, the peak intensity increases and the peak wavelength decreases.

black lead - Black lead is an alternate name for the graphite allotrope of carbon.
Also Known As: graphite, blacklead
Example: Black lead is the substance found in most pencils.

black light

block - In chemistry, block refers to the regions of the periodic table that correspond to the outermost subshell of electron orbitals. Blocks are marked by the same letters as electron orbitals: s, p, d and f. Blocks can be further defined by the energy levels of the outermost orbital.
Examples: The transition metals are all d block elements. Gold is a 5d block element. Carbon is a 2p block element.

block copolymer

blue vitriol - Blue vitriol is an outdated name for copper sulfate (CuSO4).
Also Known As: copper sulfate

body centered cubic - Body centered cubic or BCC refers to a crystal structure in which atoms are located at the corners of a cubic cell with one atom at the cell center position.


Bohr radius - The Bohr radius is the most probable distance between the proton and electron in a hydrogen atom in its ground state. This physical constant is denoted by the symbol a0 and is equal to 5.2917721092(17) x 10-11 m. In most cases, a0 is rounded to 0.529 Å.


boiling point

boiling point elevation

Boltzmann's constant - Boltzmann′s constant is the proportionality constant between the kinetic energy and temperature of molecules of an ideal gas.
Boltzmann′s constant (k or kB) is equal to the ideal gas constant (R) divided by Avogadro's number (NA).
k = R/NA = 1.3806504(24)x10-23 JK-1


bond angle

bond-dissociation energy

bond energy

bond enthalpy

bond length

bonding molecular orbital - The orbital which is formed by the overlap of adjacent atomic orbitals.

bond order

boron - Boron is the name for the element with atomic number 5 and is represented by the symbol B. It is a member of the semimetal group.

Boyle's law

branched chain alkane

branched polymer - A branched polymer is a polymer containing secondary polymer chains branching off the main chain.

brass - Brass is defined as an alloy of copper and zinc.

bremsstrahlung - Bremsstrahlung is a type of electromagnetic radiation produced when a high energy charged particle is decelerated or deflected by another charged particle.

brimstone - Brimstone is an old name for the element sulfur.

British thermal unit - British thermal unit is a unit of energy equal to the amount of heat required to raise one pound of water 1 degree Fahrenheit at a pressure of 1 atmosphere.
1 BTU ≈ 1.054 Joules ≈ 252 calories

bromination - Bromination is a chemical reaction where a bromine atom is integrated into a molecule.

bromine - Bromine is the name for the element with atomic number 35 and is represented by the symbol Br. It is a member of the halogen group.

Bronsted-Lowry acid

Bronsted-Lowry base

bronze - Bronze is an alloy of copper, usually containing tin as its main addition.

BTU - BTU is the abbreviation for the British Thermal Unit (see above)

buckminsterfullerene - A buckminsterfullerene is carbon allotrope made up of sixty atoms arranged in a sphere. The chemical formula of a buckminsterfullerene is C60. Buckminsterfullerenes are also known as 'buckyballs'.


butter - Butter is a deprecated chemical term for inorganic chlorides.
Examples: Butter of tin is SnCl4. Butter of zinc is ZnCl2.

butter of antimony - Butter of antimony is a deprecated chemistry term for the compound antimony trichloride or SbCl3.

butter of arsenic - Butter of arsenic is a deprecated chemistry term for the compound arsenic trichloride or AsCl3.

butter of bismuth - Old name for bismuth trichloride or BiCl3.

butter of tin - Old chemistry term for the compound tin(IV) chloride or SnCl4.
Also Known As: tin tetrachloride

butter of zinc - Old chemistry term for the compound zinc chloride or ZnCl.