Chemistry Dictionary
Terminology "O"
- Octahedral
- A term used to describe molecules and polyatomic ions that have one atom in
the center and six atoms at the corners of a octahedron.
- Octane Number
- A number that indicates how smoothly a gasoline burns.
- Octet Rule
- Many representative elements attain at least a share of eight electrons in
their valence shells when they form molecular or ionic compounds; there are
some limitations.
- Oil
- Liquid triester of glycerol and unsaturated fatty acids.
- Open Sextet
- Refers to species that have only six electrons in the highest energy level
of the central element (many Lewis acids).
- Optical Activity
- The rotation of plane polarized light by one of a pair of optical isomers.
- Optical Isomers
- Stereoisomers that differ only by being nonsuperimposable mirror images of
each other, like right and left hands, also called enantiomers.
- Ore
- A natural deposit containing a mineral of an element to be extracted.
- Organic Chemistry
- The chemistry of substances that contain carbon-hydrogen bonds.
- Osmosis
- The process by which solvent molecules pass through a semipermable membrane
from a dilute solution into a more concentrated solution.
- Osmotic Pressure
- The hydrostatic pressure produced on the surface of a semipermable membrane
by osmosis.
- Ostwald Process
- A process for the industrial production of nitrogen oxide and nitric acid
from ammonia and oxygen.
- Outer Orbital Complex
- Valence bond designation for a complex in which the metal ion utilizes d
orbitals in the outermost (occupied) shell in hybridization.
- Overlap
- The interaction of orbitals on different atoms in the same region of space.
- Oxidation
- An algebraic increase in the oxidation number; may correspond to a loss
of electrons.
- Oxidation Numbers
- Arbitrary numbers that can be used as mechanical aids in writing formulas
and balancing equations; for single- atom ions they correspond to the charge on
the ion; more electronegative atoms are assigned negative oxidation numbers
(also called Oxidation states).
- Oxidation-reduction Reactions
- Reactions in which oxidation and reduction occur; also called redox
reactions.
- Oxide
- A binary compound of oxygen.
- Oxidizing Agent
- The substance that oxidizes another substance and is reduced.