bonate, and sodium perborate. When
sprayed with the reagent, traces of
blood (even old blood) emit a faint
chemoluminescence.
LUMOSee lowest unoccupied mo-
lecular orbital.lutetiumSymbol Lu. A silvery
metallic element belonging to the
*lanthanoids; a.n. 71; r.a.m. 174.97;
r.d. 9.8404 (20°C); m.p. 1663°C; b.p.
3402 °C. Lutetium is the least abun-
dant of the elements and the little
quantities that are available have
been obtained by processing other
metals. There are two natural iso-
topes, lutetium–175 (stable) and
lutetium–176 (half-life 2.2 × 1010
years). The element is used as a cata-
lyst. It wasÜrst identiÜed by Gerges
Urbain (1872–1938) in 1907.
A- Information from the WebElements site
luxSymbol lx. The SI unit of illumi-
nance equal to the illumination pro-
duced by a luminousÛux of 1 lumen
distributed uniformly over an area of
1 square metre.
lyate ionThe ion formed by re-
moving a hydron from a molecule of
a solvent. In water, for example, the
hydroxide ion (OH–) is the lyate ion.lyeSee potassium hydroxide.Lyman series See hydrogen spec-
trum.lyonium ionThe ion formed by
adding a hydron (H+) to a solvent
molecule. For example, in ethanol,
C 2 H 5 OH 2 +is the lyonium ion.lyophilicHaving an afÜnity for a
solvent (‘solvent-loving’; if the sol-
vent is water the term hydrophilic is
used). See colloids.
lyophobicLacking any afÜnity for
a solvent (‘solvent-hating’; if the sol-
vent is water the term hydrophobic is
used). See colloids.lyotropic mesomorph An
arrangement taken by micelles
formed from surfactant molecules in
concentrated solutions. A lyotropic
mesomorph consists of long cylin-
ders in a fairly close-packed hexago-
nal arrangement. Lyotropic
mesomorphs are sometimes called
liquid crystalline phases for micelles.lysergic acid diethylamide (LSD)
A chemical derivative of lysergic acid
that has potent hallucinogenic prop-
erties (see hallucinogen). It occurs in
the cereal-fungus ergot and is
classiÜed as an ergot *alkaloid. LSD
wasÜrst synthesized in 1943.lysineSee amino acid.LUMO 334l