Titanium is a strong yet lightweight metal that is corrosion-resistant. It is commonly used to strengthen structural materials like aircraft and missiles. Titanium dioxide is also widely used as a white pigment in paints due to its hiding power and permanence. Zirconium is used in applications where corrosion resistance is important, like chemical industries and vacuum tubes. It is also used in alloys and refractory materials. Hafnium is primarily employed in nuclear reactor control rods due to its high neutron absorption. Rutherfordium is an artificial element with no natural occurrence or applications.

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Group IVB of the Periodical Table of Elements

2. Discovered independently by William
Gregor and Martin Klaproth in 1795,
titanium (named for the mythological
Greek Titans) was first isolated in 1910.
It is a highly corrosion-resistant metal
with great tensile strength. It is ninth in
abundance for elements in the earth's
crust.
Titanium is used for strengthening
structural materials but is also useful in
strengthening bones in the human body
where it is used to make durable repairs
since it does not react with tissue.
Most titanium metal is refined from a
mineral known as rutile, TiO2. This is an
intensely white powder that is also used
as a high-hide paint pigment.

3. Some Uses
Titanium is important as an alloying agent
with aluminum, molybdenum, manganese,
iron, and other metals. Alloys of titanium
are principally used for aircraft and
missiles where lightweight strength and
ability to withstand extremes of
temperature are important.
Titanium is as strong as steel, but 45%
lighter. It is 60% heavier than aluminum,
but twice as strong.
Titanium dioxide is extensively used for
both house paint and artist's paint, because
it is permanent and has good covering
power. Titanium oxide pigment accounts
for the largest use of the element. Titanium
paint is an excellent reflector of infrared,
and is extensively used in solar
observatories where heat causes poor
viewing conditions.

4. Zirconium is a greyish-white lustrous
metal. The finely divided metal can ignite
spontaneously in air, especially at
elevated temperatures. The solid metal is
much more difficult to ignite. The
inherent toxicity of zirconium
compounds is low. Hafnium is invariably
found in zirconium ores, and the
separation is difficult. Commercial grade
zirconium contains from 1 to 3%
hafnium. The hafnium is removed from
the zirconium used in the nuclear power
industry.
Zirconium is found in S-type stars, and
has been identified in the sun and
meteorites. Analyses of lunar rock
samples show a surprisingly high
zirconium oxide content as compared
with terrestrial rocks. Some forms of
zircon (ZrSiO4) have excellent gemstone
qualities.

5. Uses
It is used extensively by the chemical
industry where corrosive agents are
employed. Zirconium is used as a getter in
vacuum tubes, as an alloying agent in steel,
in surgical appliances, photoflash bulbs,
explosive primers, rayon spinnerets, lamp
filaments, etc. It is used in poison ivy lotions
in the form of the carbonate as it combines
with urushiol. With niobium, zirconium is
superconductive at low temperatures and is
used to make superconductive magnets,
which offer hope of direct large-scale
generation of electric power. Zirconium
oxide (zircon) has a high index of refraction
and is used as a gem material. The impure
oxide, zirconia, is used for laboratory
crucibles that will withstand heat shock, for
linings of metallurgical furnaces, and by the
glass and ceramic industries as a refractory
material. Its use as a refractory material
accounts for a large share of all zirconium
consumed.

6. Most zirconium minerals contain 1 to
3% hafnium. Hafnium is a ductile metal
with a brilliant silver lustre. Its properties
are influenced considerably by the
impurities of zirconium present. Of all the
elements, zirconium and hafnium are two
of the most difficult to separate. Hafnium is
a Group 4 transition element.
Because hafnium has a good absorption
cross section for thermal neutrons (almost
600 times that of zirconium), has excellent
mechanical properties, and is extremely
corrosion resistant, it is used for nuclear
reactor control rods.
Hafnium carbide is the most refractory
binary composition known, and the nitride
is the most refractory metal nitride (m.p.
3310°C).

7. Uses
Because the element not only has a good
absorption cross section for thermal
neutrons (almost 600 times that of
zirconium), but also excellent mechanical
properties and is extremely corrosion-
resistant, hafnium is used for reactor
control rods. Such rods are used in nuclear
submarines.
Hafnium is used in gas-filled and
incandescent lamps, and is an efficient
getter for scavenging oxygen and nitrogen.

8. In 1964 researchers in the Soviet
Union at Dubna announced their
discovery of element 104. A similar
claim was made by researchers at the
University of California at Berkeley.
The Soviet scientists claimed to have
bombarded a target of Pu-242 with
Ne-22, resulting in a nucleus with
104 protons and a mass number of
260. The Berkeley team used a Cf-249
target and isotopes of carbon for
projectiles, resulting in isotopes of 104
with mass numbers of 257 and 259.
Several other isotopes were also
prepared by the American team.
The naming and priority of discovery
controversy has raged ever since and
Rutherfordium is the approved name
selected by the IUPAC in August 1997.

9. Rutherfordium is a
synthetic element that is
not present in the
environment at all. It has
no uses.