2.
Atomic Number – 5
Melting point – 2365 K
Atomic Weight – 10.811
Boiling point – 4275 K
Electronic Configuration –
1s2 2s2 2p1
Electronegativity – 2.04
Ionization Potential – 8.298 eV
Series – Metalloid
2 Isotopes –
State – Solid
Atomic Radius – 0.98 Å
Density – 2.34 gm.cm-3
Covalent Radius – 0.82 Å
11B(80.1)
,10B (19.9%)
3.
Most of the chemistry of boron
compounds is based on the lack
of an octet of electrons about
the central boron atom.
These compounds are electrondeficient; the deficiency causes
them to exhibit some unusual
bonding features.
Some useful
compounds of Boron Borax
(Na2Ba4O7.10H2O)
Borax, a hydrated borate,
is the primary source of
boron.
Orthoboric Acid
(H3BO3)
Diborane
(B2H6)
4. Chemistry Of Boron
Elemental boron is rare and poorly studied because the
material is extremely difficult to prepare.
Most studies on boron involve samples that contain small
amounts of carbon.
Crystalline boron is chemically inert and resistant to attack by
boiling hydrofluoric or hydrochloric acid.
The rate of oxidation of boron depends upon the crystallinity,
particle size, purity and temperature. Boron does not react
with air at room temperature, but at higher temperatures it
burns to form boron trioxide.
5. Na2B4O7
.10H2O
Borax is an important boron
compound, a mineral, and a salt
of boric acid.
Powdered borax is white,
consisting of soft colorless
crystals that dissolve easily in
water.
6. USES
Ingredient in enamel glazes
Component of glass, pottery, and ceramics
Borax can be used as an additive in ceramic slips and
glazes to improve fit on wet, greenware, and bisque.
For stopping car radiator and engine block leaks
8. USES OF BORIC ACID
Boric acid can be used as an antiseptic for minor
burns or cuts.
Boric acid was first registered in the US as an
insecticide in 1948 for control of many insects.
Boric acid is used in the production of the glass in
LCD flat panel displays.
Boron is used in pyrotechnics to prevent the
amide-forming reaction between aluminum and
nitrates.
10.
USES OF DIBORANE
Diborane is a powerfull reducing
agent in organic synthesis.
Diborane is largely used in
semiconductor manufacturing.
Diborane is also used for the
production of
borophosphosilicate glasses.
It is also used to coat the walls
of tokamaks to reduce the
amount of heavy metal
impurities in the plasma.
11. USES OF BORON AND ALUMINIUM AND THEIR
COMPOUNDS
Aluminium
BORON
making bullet-proof vests.
Transportation industry
It is used in nuclear
industry, as protective
shields and control rods.
Packaging
Construction
In electronics and
CDs(highly pure aluminium
is used)
Heat sinks for electronic
appliances.
Manufacturing heat
resistant glasses,
fibreglass, glass wool etc.
Used as a mild antiseptic.
12. Questions
Why is boric acid considered a weak acid?
Why does boron trifluoride behave as a Lewis
acid?
Is boric acid a protic acid ? Why ?
On heating boric acid, what new compound will
be formed? Which compound of boron will be
formed on further heating?