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.

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


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