Mendeleev's Periodic Table > Hf - Hafnium

Hf - Hafnium

The transition element hafnium was discovered by Coster and Hevesey in 1923 in Denmark. 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).

Atomic number - 72 Density g/mL 13 .1
Atomic weight u 178 .49 Melting point K 2500
Bonding radius A 1 .44 Boiling point K 4876
Atomic radius A 2 .16 Heat of vaporization kJ/mol 575
Ionization Potential V 6 .65 Heat of fusion kJ/mol 24 .06
Electronegativity - 1 .3 Specific heat J/gK 0 .14
The oxide is amphoteric. Crystal are hexagonal.
Electron config. : [Xe] 4f14 5d2 6s2

Isotopes of Hf (Hafnium) :

MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 154
2 sec
a/EC,6.700
Yb-150/Lu-154
153.96425 		155
0.89 sec
a/EC,8.000
Yb-151/Lu-155
154.96274 		156
25 msec
a,6.033 MeV
Yb-152
155.95920 		157
110 msec
a/EC,5.880
Yb-153/Lu-157
156.95813
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 158
2.86 sec
a/EC,5.100
Yb-154/Lu-158
157.95464 		159
5.6 sec
a/EC,6.700
Yb-155/Lu-159
158.95383 		160
13.6 sec
a/EC,4.370
Yb-156/Lu-160
159.95071 		161
16.8 sec
a/EC,6.300
Yb-157/Lu-161
160.95032
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 162
37.6 sec
a/EC,3.450
Yb-158/Lu-162
161.94720 		163
40.0 sec
EC,5.500 MeV
Lu-163
162.94707 		164
111 sec
EC,2.970 MeV
Lu-164
163.94442 		165
76 sec
EC,4.600 MeV
Lu-165
164.94449
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 166
6.77 min
EC,2.300 MeV
Lu-166
165.94224 		167
2.05 min
EC,4.000 MeV
Lu-167
166.94259 		168
25.95 min
EC,1.800 MeV
Lu-168
167.94063 		169
3.24 min
EC,3.270 MeV
Lu-169
168.94115
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 170
16.01 hr
EC,1.100 MeV
Lu-170
169.93964 		171
12.1 hr
EC,2.400 MeV
Lu-171
170.94049 		172
1.87 yr
EC,8.600 MeV
Lu-172
171.93946 		173
23.6 hr
EC,1.610 MeV
Lu-173
172.94065
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 174 0.162%
2.0E15 yr
a,2.495 MeV
Yb-170
173.94004 		175
70 da
EC,6.782 MeV
Lu-175
174.94150 		176 5.206%

Stable

175.94140 		177 18.606%

Stable

176.94322
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 178 27.297%

Stable

177.94369 		179 13.629%

Stable

178.94581 		180 35.100%

B-Stable
Ta-180
179.94654 		181
42.39 da
B-,1.027 MeV
Ta-181
180.94909
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 182
9E+6 yr
B-,9.300 MeV
Ta-182
181.95055 		183
1.067 hr
B-,2.010 MeV
Ta-183
182.95352 		184
4.12 hr
B-,1.340 MeV
Ta-184
183.95544 		184a
48 sec
B-,1.340 MeV
Ta-184
183.95544
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 185
3.5 min
B-,6.000 MeV
Ta-185
184.95902