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Properties of substance:
hafnium
Group of substances:
inorganic
Physical appearance:
hexagonal metal
Empirical formula (Hill's system for organic substances):
Hf
Structural formula as text:
Hf
Molar/atomic mass: 178.49
Melting point (°C):
2220
Boiling point (°C):
4600
Solubility (g/100 g of solvent):
mercury
: insoluble [
Ref.
]
water
: insoluble [
Ref.
]
Numerical data:
Year of discovery: 1923
Density:
13.31 (20°C, g/cm
3
)
Half-life:
154
72
Hf = 2 s (β
+
(about 100%))
155
72
Hf = 890 ms (β
+
(about 100%))
156
72
Hf = 23 ms (α (97%))
156m
72
Hf = 480 μs (α (100%))
157
72
Hf = 115 ms (α (86%), β
+
(14%))
158
72
Hf = 2.84 s (α (45%), β
+
(55%))
159
72
Hf = 5.2 s (β
+
(65%), α (35%))
160
72
Hf = 13.6 s (β
+
(99.3%), α (0.7%))
161
72
Hf = 18.2 s (β
+
(about 100%), α)
162
72
Hf = 39.4 s (β
+
(about 100%), α (0.008%))
163
72
Hf = 40 s (β
+
(about 100%), α)
164
72
Hf = 111 s (β
+
(100%))
165
72
Hf = 76 s (β
+
(100%))
166
72
Hf = 6.77 min (β
+
(100%))
167
72
Hf = 2.05 min (β
+
(100%))
168
72
Hf = 25.95 min (electron capture (about 98%), β
+
(about 2%))
169
72
Hf = 3.24 min (β
+
(100%))
170
72
Hf = 16.01 h (electron capture (100%))
171
72
Hf = 12.1 h (β
+
(100%))
171m
72
Hf = 29.5 s (internal transition (about 100%))
172
72
Hf = 1.87 y (electron capture (100%))
172m
72
Hf = 163 ns ()
173
72
Hf = 23.6 h (β
+
(100%))
174
72
Hf = 2 · 10
15
y (α (100%) (isotopic abundance 0,16%))
174m
72
Hf = 2.39 μs (internal transition (100%))
175
72
Hf = 70 d (electron capture (100%))
176
72
Hf = stable ( (isotopic abundance 5,26%))
177
72
Hf = stable ( (isotopic abundance 18,6%))
177m
72
Hf = 1.09 s (internal transition (100%))
177n
72
Hf = 51.4 min (internal transition (100%))
177p
72
Hf = 55.9 μs (internal transition (100%))
178
72
Hf = stable ( (isotopic abundance 27,28%))
178m
72
Hf = 4.0 s (internal transition (100%))
178n
72
Hf = 31 y (internal transition (100%))
178p
72
Hf = 68 μs (internal transition (100%))
179
72
Hf = stable ( (isotopic abundance 13,62%))
179m
72
Hf = 18.67 s (internal transition (100%))
179n
72
Hf = 25.05 d (internal transition (100%))
180
72
Hf = stable ( (isotopic abundance 35,08%))
180m
72
Hf = 5.5 h (internal transition (about 100%))
181
72
Hf = 42.39 d (β
-
(100%))
181m
72
Hf = 80 μs (internal transition (100%))
181n
72
Hf = 100 μs (internal transition (100%))
181p
72
Hf = 1.5 ms (internal transition (100%))
182
72
Hf = 9 000 000 y (β
-
(100%))
182m
72
Hf = 61.5 min (β
-
(58%), internal transition (42%))
183
72
Hf = 1.067 h (β
-
(100%))
184
72
Hf = 4.12 h (β
-
(100%))
184m
72
Hf = 48 s (β
-
(100%))
185
72
Hf = 3.5 min (β
-
(100%))
186
72
Hf = 2.6 min (β
-
(100%))
187
72
Hf = 30 s (about) ()
Vapour pressure (Torr):
0.1 (2870°C)
1 (3205°C)
10 (3700°C)
100 (4440°C)
Electrode potential:
Hf
4+
+ 4e
-
→ Hf, E = -1.7 V (water, 25°C)
Standard molar enthalpy (heat) of formation Δ
f
H
0
(298.15 K, kJ/mol):
0 (s)
Standard molar Gibbs energy of formation Δ
f
G
0
(298.15 K, kJ/mol):
0 (s)
Standard molar entropy S
0
(298.15 K, J/(mol·K)):
43.55 (s)
Molar heat capacity at constant pressure C
p
(298.15 K, J/(mol·K)):
25.7 (s)
Molar enthalpy (heat) of fusion Δ
fus
H (kJ/mol):
21
Enthalpy (heat) of vaporization Δ
vap
H (kJ/mol):
569
References:
Гурвич Я.А. Справочник молодого аппаратчика-химика. - М.: Химия, 1991. - pp. 48, 50 [Russian]
Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 61 [Russian]
Шека И.А., Карлышева К.Ф. Химия гафния. - Киев: Наукова думка, 1973 [Russian]
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© Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru
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