CL
cl adj 1 :
being ten more than one hundred forty [
synonym : {
one hundred fifty }, {
150 }, {
cl }]
n 1 :
a common nonmetallic element belonging to the halogens ;
best known as a heavy yellow irritating toxic gas ;
used to purify water and as a bleaching agent and disinfectant ;
occurs naturally only as a salt (
as in sea water ) [
synonym :
{
chlorine }, {
Cl }, {
atomic number 17 }]
2 :
a metric unit of volume equal to one hundredth of a liter [
synonym : {
centiliter }, {
centilitre }, {
cl }]
Ion \
I "
on \ ([
imac ]"[
o ^]
n ),
n . [
Gr . '
io `
n ,
neut ,
of '
iw `
n ,
p .
pr .
of '
ie `
nai to go .]
1 . (
Elec .
Chem .)
an atom or goup of atoms (
radical )
carrying an electrical charge .
It is contrasted with neutral atoms or molecules ,
and free radicals .
Certain compounds ,
such as sodium chloride ,
are composed of complementary ions in the solid (
crystalline )
as well as in solution .
Others ,
notably acids such as hydrogen chloride ,
may occur as neutral molecules in the pure liquid or gas forms ,
and ionize almost completely in dilute aqueous solutions .
In solutions (
as in water )
ions are frequently bound non -
covalently with the molecules of solvent ,
and in that case are said to be solvated .
According to the electrolytic dissociation theory ,
the molecules of electrolytes are divided into ions by water and other solvents .
An ion consists of one or more atoms and carries one unit charges of electricity ,
3 .
4 x 10 ^{-
10 }
electrostatic units ,
or a multiple of this .
Those which are positively electrified (
hydrogen and the metals )
are called {
cations };
negative ions (
hydroxyl and acidic atoms or groups )
are called {
anions }.
Note :
Thus ,
hydrochloric acid ({
HCl })
dissociates ,
in aqueous solution ,
into the hydrogen ion , {
H },
and the chlorine ion , {
Cl -};
ferric nitrate , {
Fe (
NO3 )
3 },
yields the ferric ion , {
Fe },
and nitrate ions , {
NO3 -}, {
NO3 -},
{
NO3 -}.
When a solution containing ions is made part of an electric circuit ,
the cations move toward the cathode ,
the anions toward the anode .
This movement is called migration ,
and the velocity of it differs for different kinds of ions .
If the electromotive force is sufficient ,
electrolysis ensues :
cations give up their charge at the cathode and separate in metallic form or decompose water ,
forming hydrogen and alkali ;
similarly ,
at the anode the element of the anion separates ,
or the metal of the anode is dissolved ,
or decomposition occurs .
Aluminum and chlorine are elements prepared predominantly by such electrolysis ,
and depends on dissolving compounds in a solvent where the element forms ions .
Electrolysis is also used in refining other metals ,
such as copper and silver .
Cf .
{
Anion }, {
Cation }.
[
Webster 1913 Suppl .]
2 .
One of the small electrified particles into which the molecules of a gas are broken up under the action of the electric current ,
of ultraviolet and certain other rays ,
and of high temperatures .
To the properties and behavior of ions the phenomena of the electric discharge through rarefied gases and many other important effects are ascribed .
At low pressures the negative ions appear to be electrons ;
the positive ions ,
atoms minus an electron .
At ordinary pressures each ion seems to include also a number of attached molecules .
Ions may be formed in a gas in various ways .
[
Webster 1913 Suppl .]
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