ferrochelatase An ENZYMEthat catalyzes the insertion
of iron into PROTOPORPHYRIN IXto form HEME. The
mammalian enzyme contains an IRON-SULFUR CLUSTER.
ferroheme An iron(II) PORPHYRIN COORDINATION
complex.
ferromagnetic If there is coupling between the indi-
vidual magnetic dipole moments of a PARAMAGNETIC
sample, spontaneous ordering of the moments will
occur at low temperatures. If this ordering results in an
electronic GROUND STATEin which the moments are
aligned in the same direction (parallel), the substance is
said to be ferromagnetic. If the ordering results in an
electronic ground state in which the moments are
aligned in opposite directions, the substance is said to
be antiferromagnetic.
ferrous metal A metal composed chiefly of iron.
field effect An experimentally observable effect—
symbolized by F (on reaction rates, etc.) of
INTRAMOLECULARcoulombic interaction between the
center of interest and a remote unipole or dipole—by
direct action through space rather than through bonds.
The magnitude of the field effect (or direct effect)
depends on the unipolar charge/dipole moment, orien-
tation of dipole, shortest distance between the center of
interest and the remote unipole or dipole, and on the
effective dielectric constant.
See alsoELECTRONIC EFFECT; INDUCTIVE EFFECT;
POLAR EFFECT.
filter A device, instrument, or material that removes
something from whatever passes through it.
filtration The passage of a liquid or material through
a FILTER, utilizing gravity, pressure, or vacuum (suction).
first law of thermodynamics Simply put, energy
can neither be created nor destroyed, only transformed
or transferred from one molecule to another; in effect,
the total amount of energy in the universe is constant.
Also known as the law of conservation of energy.
THERMODYNAMICSis the study of the conversion of
energy between heat and other forms, e.g., mechanical.
See alsoSECOND LAW OF THERMODYNAMICS.Fischer, Hermann Emil (1852–1919) German
Chemist Hermann Emil Fischer was born on October
9, 1852, in Euskirchen (the Cologne district). He spent
three years with a private tutor, then attended local
school. He then spent two years in school at Wetzlar
and two more at Bonn, passing in 1869 with great dis-
tinction. Instead of going into his family’s lumber busi-
ness, he went to the University of Bonn in 1871,
originally studying chemistry but later changing to
physics and mineralogy.
The following year he attended the new University
of Strasbourg with his cousin Otto Fischer and became
influenced by Adolf von Baeyer. Studying under von
Baeyer, Fischer received his Ph.D. in 1874 for his work
on fluoresceine and orcin-phthalein. In the same year
he was appointed assistant instructor at Strasbourg
University and discovered the first hydrazine base,
phenylhydrazine, and demonstrated its relationship to
hydrazobenzene and to a sulfonic acid described by
Strecker and Römer.
In 1875 von Baeyer became an assistant in organic
chemistry, succeeding Liebig at the University of
Munich. In 1878 he qualified as a privatdozent at
Munich and was appointed associate professor of ana-
lytical chemistry in 1879 after refusing the chair of
chemistry at Aix-la-Chapelle. In 1881 he was
appointed professor of chemistry at the University of
Erlangen. In 1888 he became professor of chemistry at
the University of Würzburg until 1892, and then suc-
ceeded A. W. Hofmann in the chair of chemistry at the
University of Berlin, where he stayed until his death in
1919.
He and his cousin Otto continued to work on
hydrazines, and both worked out a new theory of the
constitution of the dyes derived from triphenylmethane,
which they proved through experimentation.
While at Erlangen, Fischer studied the active prin-
ciples of tea, coffee, and cocoa (caffeine and theo-
bromine) and eventually synthesized them. Between
1882 and 1906, his work on purines and sugars gainedFischer, Hermann Emil 109