anthocyanin One of a group of
*Ûavonoid pigments. Anthocyanins
occur in various plant organs and are
responsible for many of the blue,
red, and purple colours in plants
(particularly in Ûowers).
anthracene A white crystalline
solid, C 14 H 10 ; r.d. 1.28; m.p. 215.8°C;
b.p. 341.4°C. It is an aromatic hydrocarbon with three fused rings (see
formula), and is obtained by the distillation of crude oils. The main use
is in the manufacture of dyes.
anthocyanin
40
a
O
O
1
2
3
4
5
6
7
8
Anthraquinone
anthracite See coal.
anthraquinone A colourless crystalling *quinone; m.p. 154°C. It may
be prepared by reacting benzene
with phthalic anhydride. The compound is the basis of a range of
dyestuffs. *Alizarin is an example.
anti 1. See torsion angle. 2. See
e–z convention.
antiaromatic See pseudoaromatic.
antibiotics Substances that destroy
or inhibit the growth of microorganisms, particularly disease-producing
bacteria. Antibiotics are obtained
from microorganisms (especially
moulds) or synthesized. Common
antibiotics include the penicillins,
streptomycin, and the tetracyclines.
They are used to treat various infections but tend to weaken the body’s
natural defence mechanisms and can
cause allergies. Overuse of antibiotics
can lead to the development of resistant strains of microorganisms.
antibonding orbital See orbital.
anticlinal See torsion angle.
antiferromagnetism See magnetism.
antiÛuorite structure A crystal
structure for ionic compounds of the
type M 2 X, which is the same as the
Ûuorite (CaF 2 ) structure except that
the positions of the anions and
cations are reversed, i.e. the cations
occupy the F
– sites and the anions occupy the Ca
2+ sites. Examples of the
antiÛuorite structure are given by
K 2 O and K 2 S. See fluorite structure.
antifoaming agent A substance
that prevents a foam from forming,
employed in such processes as electroplating and paper-making, and in
water for boilers. They are compounds that are absorbed strongly by
the liquid (usually water) but lack the
properties that allow foaming. Substances used include polyamides,
polysiloxanes and silicones.
antifreeze A substance added to
the liquid (usually water) in the cooling systems of internal-combustion
Anthracene
O
R
R
R
R
R
R
R
+
Anthocyanin
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*Ûavonoid pigments. Anthocyanins
occur in various plant organs and are
responsible for many of the blue,
red, and purple colours in plants
(particularly in Ûowers).
anthracene A white crystalline
solid, C 14 H 10 ; r.d. 1.28; m.p. 215.8°C;
b.p. 341.4°C. It is an aromatic hydrocarbon with three fused rings (see
formula), and is obtained by the distillation of crude oils. The main use
is in the manufacture of dyes.
anthocyanin
40
a
O
O
1
2
3
4
5
6
7
8
Anthraquinone
anthracite See coal.
anthraquinone A colourless crystalling *quinone; m.p. 154°C. It may
be prepared by reacting benzene
with phthalic anhydride. The compound is the basis of a range of
dyestuffs. *Alizarin is an example.
anti 1. See torsion angle. 2. See
e–z convention.
antiaromatic See pseudoaromatic.
antibiotics Substances that destroy
or inhibit the growth of microorganisms, particularly disease-producing
bacteria. Antibiotics are obtained
from microorganisms (especially
moulds) or synthesized. Common
antibiotics include the penicillins,
streptomycin, and the tetracyclines.
They are used to treat various infections but tend to weaken the body’s
natural defence mechanisms and can
cause allergies. Overuse of antibiotics
can lead to the development of resistant strains of microorganisms.
antibonding orbital See orbital.
anticlinal See torsion angle.
antiferromagnetism See magnetism.
antiÛuorite structure A crystal
structure for ionic compounds of the
type M 2 X, which is the same as the
Ûuorite (CaF 2 ) structure except that
the positions of the anions and
cations are reversed, i.e. the cations
occupy the F
– sites and the anions occupy the Ca
2+ sites. Examples of the
antiÛuorite structure are given by
K 2 O and K 2 S. See fluorite structure.
antifoaming agent A substance
that prevents a foam from forming,
employed in such processes as electroplating and paper-making, and in
water for boilers. They are compounds that are absorbed strongly by
the liquid (usually water) but lack the
properties that allow foaming. Substances used include polyamides,
polysiloxanes and silicones.
antifreeze A substance added to
the liquid (usually water) in the cooling systems of internal-combustion
Anthracene
O
R
R
R
R
R
R
R
+
Anthocyanin
www.AzShimi.ir www.AzShimi.com