him fame. In 1906 he was awarded the Nobel Prize in
chemistry for his work in this area.
Fischer was awarded the Prussian Order of Merit
and the Maximilian Order for Arts and Sciences.
In 1888 he married Agnes Gerlach, daughter of J.
von Gerlach, professor of anatomy at Erlangen, but she
died seven years into their marriage after bearing three
sons. Fischer died in Berlin on July 15, 1919. The Ger-
man Chemical Society instituted the Emil Fischer
Memorial Medal in 1919.
fission SeeNUCLEAR FISSION.
flammable A liquid having a flash point below
37.8°C (100°F).
flash point The temperature at which liquids yield
enough flammable vapor to ignite. It is the lowest tem-
perature at which a liquid can form an ignitable mix-
ture in air near the surface of the liquid. The lower the
flash point, the easier it is to ignite.
flash vacuum pyrolysis (FVP) Thermal reaction of
a molecule by exposing it to a short thermal shock at
high temperature, usually in the gas phase.
flavin A PROSTHETIC GROUPfound in flavoproteins and
involved in biological oxidation and reduction. Forms
the basis of natural yellow pigments like riboflavin.
flocculation Coagulation of colloidal particles due to
the ions in solution.
flotation A method to separate water-repelling
(HYDROPHOBIC) ore particles from water-attracting
(HYDROPHILIC) particles.fluids All substances that flow freely, such as gases
and liquids.fluorescence When colors absorb radiant power at
one wavelength and immediately reemit it at another
(usually longer) wavelength. The property of giving off
light at a particular wavelength (emission wavelength)
after it is illuminated by light of a different wavelength
(excitation wavelength).fluorination A process in which a thermoplastic con-
tainer or closure is exposed to fluorine gas to improve
barrier properties and reduce solvent absorption and
permeation. Also refers to the introduction of a fluo-
rine atom into a molecule.flux A substance added to react with a material to
lower a melting point. A material used to remove
oxides that form on metal surfaces exposed to oxygen
in the air. In nuclear terms, the amount of some type of
particle (neutrons, alpha radiation, etc.) or energy
(photons, heat, etc.) crossing a unit area per unit time.
The unit of flux is the number of particles, energy, etc.
per square centimeter per second.fluxional In inorganic chemistry, this term is used to
designate positional changes among LIGANDs. A flux-
ional chemical species undergoes rapid (degenerate)
rearrangements, generally detectable by methods that
observe the behavior of individual nuclei in a rear-
ranged chemical species.foam A colloidal suspension of a gas in a liquid.folate coenzymes A group of heterocyclic com-
pounds that are based on the 4-(2-amino-3,4-dihydro-
4-oxopteridin-6-ylmethylamino)benzoic acid (pteroic110 fission