Ta

Ta - Tantalum

Tantalum, the third member of the acid earth family, is a hard metal with reactivity lower even than platinium. The 'element' columbium was discovered in columbite minerals from Connecticut by Charles Hatchett in 1801. Columbium however was shown to be two metals one of which was was tantalum. (The other was niobium.) Tantalum oxide was isolated by Anders G. Ekeberg in 1802 who then named the element because it tantalized his efforts to purify the metal. The pure metal was finally obtained, electrochemically, by Bolton in 1905.

A tantalum ball from an India ink pen is illustrated.


Atomic number - 73 Density g/mL 16 .6
Atomic weight u 180 .9479 Melting point K 3287
Bonding radius A 1 .34 Boiling point K 5731
Atomic radius A 2 .09 Heat of vaporization kJ/mol 743
Ionization Potential V 7 .89 Heat of fusion kJ/mol 31 .6
Electronegativity - 1 .5 Specific heat J/gK 0 .14
The oxide is mildly acidic.
Crystal are body centered cubic.

Electron config. : [Xe] 4f14 5d3 6s2

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac** Rf Db Sg Bh Hs Mt 110 111 112
 
Lanthanides* Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Actinides ** Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Isotopes of Ta: Click mass number for decay process, product for element page.
156
0.11 sec
EC/p,1.029
Hf-156/Hf-155
155.97165 		157
5.3 msec
a,6.380 MeV
Lu-153
156.96811 		158
36.8 msec
a/EC,6.210
Lu-154/Hf-158
157.96639 		159
0.57 sec
a/EC,5.750
Lu-155/Hf-159
158.96296 		160
1.55 sec
a/EC,9.900
Lu-156/Hf-160
159.96135 		161
3.00 sec
a/EC,7.490
Lu-157/Hf-161
160.95837 		162
3.60 sec
a/EC,9.260
Lu-158/Hf-162
161.95714
163
11.0 sec
a/EC,6.800
Lu-159/Hf-163
162.95432 		164
14.2 sec
EC,8.500 MeV
Hf-164
163.95362 		165
31.0 sec
EC,5.800 MeV
Hf-165
164.95082 		166
31.5 sec
EC,7.700 MeV
Hf-166
165.95050 		167
1.33 min
EC,5.000 MeV
Hf-167
166.94793 		168
2.0 min
EC,6.700 MeV
Hf-168
167.94782 		169
4.9 min
EC,4.440 MeV
Hf-169
168.94591
170
6.76 min
EC,6.000 MeV
Hf-170
169.94608 		171
23.3 min
EC,3.700 MeV
Hf-171
170.94445 		172
36.8 min
EC,4.920 MeV
Hf-172
171.94474 		173
3.14 hr
EC,2.790 MeV
Hf-173
172.94364 		174
1.05 hr
EC,3.850 MeV
Hf-174
173.94416 		175
10.5 hr
EC,2.000 MeV
Hf-175
174.94364 		176
8.09 hr
EC,3.110 MeV
Hf-176
175.94474
177
56.56 hr
EC,1.166 MeV
Hf-177
176.94447 		178
9.31 min
EC,1.910 MeV
Hf-178
177.94575 		179
1.82 yr
EC,1.106 MeV
Hf-179
178.94593 		180
8.152 hr
B-/EC,1.141
W-180/Hf-180
179.94746 		181 99.988%

Stable

180.94799 		182
114.43 da
B-,1.814 MeV
W-182
181.95015 		183
5.1 da
B-,1.070 MeV
W-183
182.95137
184
8.7 hr
B-,2.870 MeV
W-184
183.95400 		185
49.4 min
B-,1.992 MeV
W-185
184.95555 		186
10.5 min
B-,3.900 MeV
W-186
185.95855 		MASS abund.
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass

Updated by clh on 4/28/97.