Physical Properties of Potassium

Atomic number 19
Atomic weight (based on C=12) 39.102
Natural isotopes (mass number) 39, 40, 41
Istotopic abundance 93.10%, 0.012%, 6.88%
Absorption cross-section to 0.025-ev (thermal) neutrons 2.1 barns
Total cross-section to 0.025-ev (thermal) neutrons 4.3 barns
Ionization potential 4.318 volts
Melting point 63.2°C (146°F)
Boiling point 756.5°C (1394°F)
Volume increase on melting 2.4%
Latent heat of fusion 14.2 cal/g
Latent heat of vaporization at the boiling point 474 cal/g
Critical temperature 2287°K (estimate)
Critical pressure 167 atm (estimate)
Critical volume 0.216 cm3/gram-mole (estimate)
Density (solid) 20°C
m.p.
0.855 g/cm3
0.848 g/cm3
Density (liquid) m.p.
100°C

400°C
550°C
b.p.
0.828 g/cm3
0.819 g/cm3
0.750 g/cm3
0.715 g/cm3
0.664 g/cm3
Specific volume (saturated vapor) 400°C
550°C
b.p.
1.7 x 105 g/cm3
2.2 x 104 g/cm3
1.8 x 103 g/cm3
Viscosity (liquid) 100°C
400°C
550°C
b.p.
0.472 centipoise
0.216 centipoise
0.167 centipoise
0.130 centipoise
Surface tension m.p.
100C

400°C
550°C
b.p.
111 dynes/cm
109 dynes/cm
90 dynes/cm
80 dynes/cm
67 dynes/cm
Electrical resistivity (solid) 20°C
m.p.
4.7 µΩcm
6.5 µΩcm (estimate)
Electrical resistivity (liquid) m.p.
100°C
400°C
550°C
b.p.
12.0 µΩcm
14.3 µΩcm
34.5 µΩcm
47.3 µΩcm
70.5 µΩcm
Thermal conductivity (solid) 20°C
m.p.
1.08 W/cm-°C (estimate)
1.05 W/cm-°C (estimate)
Thermal conductivity (liquid) m.p.
100°C
400°C
550°C
b.p.
0.540 W/cm-°C
0.522 W/cm-°C
0.408 W/cm-°C
0.364 W/cm-°C
0.307 W/cm-°C
Specific heat (solid) 20°C
m.p.
0.184 cal/g-°C
0.193 cal/g-°C
Specific heat (liquid) m.p.
100°C

400°C
550°C
b.p.
0.197 cal/g-°C
0.194 cal/g-°C
0.182 cal/g-°C
0.182 cal/g-°C
0.187 cal/g-°C

Source: Sodium-NaK Engineering Handbook, Volume 1
Note: Creative Engineers takes no responsibility for the accuracy of this information.