Ta at. wt. 180.948
at. no. 73
m.p. 2996°C
b.p. 5425±°C
sp.gr. 16.654
valence 2? 3? 4? or 5.
Electronic configuration
K
L
M
N
O
P
Q
1
2
3
4
5
6
7
s
s p
s p d
s p d f
s p d f
s p d f
s p d f
1
TANTALUM (Or. Tantalos, mythological character
father of Niobe), Ta; at. wt. 180.948; at. no.73; m.p.
29960C; b.p. 5425+ 1000C; sp. gr. 16.654; valence 2~ 3 49
or 5. Discovered in 1802 by Iikeberg, but many chemists
thought niobium and tantalu~m were identical elements until
Rose, in 1844, and Marignac, in 1866, indicated and
showed that. niobic and tantalic acids were two different
acids. The early investigators only isolated the impure metal.
The first relatively pure ductile tantalitm was produced by
von Bolton in 1903. Tantalum occurs principally in the
mineral columbhe-tantalite (Fe, Mn) (Nb, Ta)206. Tan-
talum ores are found in the Republic of Congo, Brazil,
Mozambique, Thailand, Portugal, Nigeria, and Canada.
The..new mine at Bernic Lake, Manitoba, has reserves of
more than a million tons of ore averaging about A % tan-
talum oxide. Separation of tantalum from niobium requires
several complicated steps. Several methods are commer-
cially used to produce the element including: electrolysis of
molten potassium fluotaptalate, reduction of potassium
fluotantalate with sodium, or reacting tantalum carbide
with tantalum oxide. Sixteen isotopes of tantalum are
known to exist. Natural tantalum contains two isotopes;
one of 'these, Ta170, .is present in very small quantity
(0.0123%) and is unstable with a very long half-life of
> l0'~ yrs. Tantalum is a gray, heavy, and very hard metal.
When pure, it is ductile and can be drawn into fine wire,
which is used as a filament for evaporating metals', such as
aluminum. Tantalum is almost completely immune 'to.
chemical attack at temperatures below 1 500C, and is
attacked only by hydrofluoric acid, acidic solutions con-
taining the fluoride ion, and free sulfur trioxide. Alkalis
attack it only slowly.' At higher temperatures, tantalum
becomes much more reactive. The element has a melting
point exceeded only by tungsten and rhenium. Tantalum is
used to make a variety of alloys with 4esirable properties,
such as high-melting point, high strength, good ductility,
etc. The metal has good "gettering" ability at high tem-
peratures, and tantalum oxide films are stable, and have
good rectifying and dielectric proterties. Tantalum is used
to make electrolytic capacitors and vacuum furnace parts,
which account for about 70'% of its use. The metal is alSo
widely used to fabricate chemical process, equipment,
nuclear reactors, and airctaft and missile parts. Tantalum
is completely immune to body liquids and is a nonirritatjng
metal. It has, therefore, found wide use in making surgical
appliances. Tantalum oxide is used to make special glass
with a high index of refractiOn for camera lenses. The
metal has many other uses. The metal in powdered form
costs about 535/lb. Sheet tantalum and fabricated forms are
more expensive.
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