Compounds of Phosphorous- Phosphorous pentachloride
Compounds of Phosphorous can be vital for life and can also be extremely dangerous.
One such lethal compound of phosphorous is Phosphorous pentachloride.
Phosphorous pentachloride is a yellowish-white powder.
Its chemical formula is
P
C
l
5
.
In gaseous and liquid form it has a trigonal bipyramidal structure.
Out of the 5 P-Cl bonds, 3 of the bonds are equatorial bonds, which are directed towards the three corners of the triangle.
The other 2 bonds above and below the plane of the triangle are axial bonds.
The axial bonds experience more repulsion than the equatorial bond pairs, hence they are longer.
In the solid state, it exists as an ionic solid ,
[
P
C
l
4
]
+
[
P
C
l
6
]
–
.
In this form, the cation
[
P
C
l
4
]
+
is tetrahedral and the anion,
[
P
C
l
6
]
–
is octahedral.
Moving on, let us look at its preparation.
P
C
l
5
is produced by the reaction of white phosphorus with an excess of dry chlorine.
It can also be produced by the action of
S
O
2
C
l
2
on phosphorus.The reaction can be represented like this:
Next up let’s look at the chemical reactions that this pentachloride undergoes.
In the presence of moist air, it hydrolyses to form
P
O
C
l
3
.
P
O
C
l
3
is further converted to phosphoric acid.
Also, Phosphorous pentachloride undergoes reactions with organic compounds to give haloalkanes and acyl halides.
In this,
P
C
l
5
reacts with organic compounds containing –OH group in reactions like this:
Finally, let us look at the reaction of phosphorous pentachloride with metals.
In this, finely divided metals on heating with
P
C
l
5
give corresponding chlorides.
Revision
P
C
l
5
is a yellowish-white powder.
In gaseous and liquid form it has a trigonal bipyramidal structure.
In the solid-state, it exists as an ionic solid,
[
P
C
l
4
]
+
[
P
C
l
6
]
–
.
P
C
l
5
can be produced by the reaction of white phosphorus with an excess of dry chlorine.
It can also be produced by the action of
S
O
2
C
l
2
on phosphorus.
The End !