Chemistry Reference
In-Depth Information
Ångstrom unit (Å)
A unit of length, one ten-millionth of a millimeter or one ten-
thousandth of a
micrometer
long.
anhydrous
Without water.
animal fibers
See fibers, animal
.
anion
An
ion
having a negative electric charge.
anisotropic
Matter
that exhibits different property values when tested along dif-
ferent directions; see
isotropic.
annealing
A
thermal process
for the removal of internal stresses and/or the hard-
ness from objects made of
glass
,
metals
, or
alloys
; it entails heating the object,
holding it for some time at a relatively high temperature, and finally cooling to
ambient temperature at a relatively slow rate.
annual growth ring
A growth layer of
wood
produced by a tree in a single year, as
seen on a transverse section of a trunk or branch; see
dendrochronology
.
anode
The positive terminal on an electric source or circuit; see
cathode
.
anthropogenic
Produced by or related to human activity.
anthroposoil
See
archaeological soil
.
antibody
A
protein
produced by the body of animals and circulated in the blood-
stream in response to foreign substances to help the body fight disease.
antimoniate
A complex
anion
composed of
atoms
of antimony and oxygen and
assigned the
formula
SbO
3
−
or SbO
4
3+
.
antimony oxide
A
glass opacifier
.
antimony red
A
mineral
composed of antimony pentasulfide, used as a red
pigment
and
stain
.
antiparallel
Two objects that lie along a common line but in opposite directions to
each other.
aplastic material
See
temper
.
aqueous
Watery.
aragonite
A
mineral
composed of calcium carbonate, of which it is a
polymorph
; see
calcite.
Ar-Ar dating
Abbreviation for
argon-argon dating
.
archaeology
The study of the human past based on its material remains.
archaeomagnetic dating
See
dating
,
archaeomagnetic
.
archaeometallurgy
Study of the
metals
and
alloys
used in antiquity and the ancient
metallurgical
processes.
argentarium
An
alloy
of lead and tin containing 50% tin; it was used by the Romans
for
tinning
.
argon-40
An
isotope
of the
inert
, gaseous
element
argon produced by the
radioactive
decay
of the isotope
potassium-40
, used for
dating minerals
and
rocks
.
argon-argon dating (Ar-Ar dating)
See
dating
,
argon-argon
(
Ar-Ar dating
).
arsenical bronze
See
arsenical copper
.
