lattice. It occurs only with polar sol-
vents. Solvation in which the solvent
is water is called hydration.
Solvay process (ammonia–soda
process) An industrial method of
making sodium carbonate from cal-
cium carbonate and sodium chloride.
The calcium carbonate isÜrst heated
to give calcium oxide and carbon
dioxide, which is bubbled into a solu-
tion of sodium chloride in ammonia.
Sodium hydrogencarbonate is precip-
itated:
H 2 O + CO 2 (g) + NaCl(aq) + NH 3 (aq)
→NaHCO 3 (s) + NH 4 Cl(aq)The sodium hydrogencarbonate is
heated to give sodium carbonate and
carbon dioxide. The ammonium chlo-
ride is heated with calcium oxide
(from theÜrst stage) to regenerate
the ammonia. The process was
patented in 1861 by the Belgian
chemist Ernest Solvay (1838–1922).
solventA liquid that dissolves an-
other substance or substances to
form a *solution. Polar solvents are
compounds such as water and liquid
ammonia, which have dipole mo-
ments and consequently high dielec-
tric constants. These solvents are
capable of dissolving ionic com-
pounds or covalent compounds that
ionize (see solvation). Nonpolar sol-
ventsare compounds such as
ethoxyethane and benzene, which do
not have permanent dipole mo-
ments. These do not dissolve ionic
compounds but will dissolve nonpo-
lar covalent compounds. Solvents can
be further categorized according to
their proton-donating and accepting
properties. Amphiprotic solvents self-
ionize and can therefore act both as
proton donators and acceptors. A typ-
ical example is water:
2H 2 O ˆH 3 O++ OH–Aprotic solvents neither accept nor
donate protons; tetrachloromethane
(carbon tetrachloride) is an example.solvent extractionThe process of
separating one constituent from a
mixture by dissolving it in a solvent
in which it is soluble but in which
the other constituents of the mixture
are not. The process is usually carried
out in the liquid phase, in which case
it is also known as liquid–liquid ex-
traction. In liquid–liquid extraction,
the solution containing the desired
constituent must be immiscible with
the rest of the mixture. The process
is widely used in extracting oil from
oil-bearing materials.
solvolysisA reaction between a
compound and its solvent. See hy-
drolysis.somanA highly toxic colourless
volatile liquid, C 7 H 16 FO 2 P; r.d. 1.02;
m.p. –42°C; b.p. 198°C. It is an
organophosphorus compound, O-
pinacolyl methylphosphonoÛuori-
date. Soman was discovered in 1944
and belongs to the G-series of *nerve
agents (GD).SOMOSingly occupied molecular
orbital.sonochemistryThe study of chem-
ical reactions in liquids subjected to
high-intensity sound or ultrasound.
This causes the formation, growth,
and collapse of tiny bubbles within
the liquid, generating localized cen-
tres of very high temperature and
pressure, with extremely rapid cool-
ing rates. Such conditions are suit-
able for studying novel reactions,
decomposing polymers, and produc-
ing amorphous materials.sorbitolA polyhydric alcohol,
CH 2 OH(CHOH) 4 CH 2 OH, derived from
glucose; it is isomeric with *manni-
tol. It is found in rose hips and rowan
berries and is manufactured by the
catalytic reduction of glucose with495 sorbitol
s