Sodium–potassium alloy

Sodium–potassium alloy
Sodium–potassium alloy
	Sodium–potassium alloy under mineral oil.
Material type	metal alloy
Physical properties
Density (ρ)	0.866 g/cm3, 20 °C (68 °F); 0.855 g/cm3, 100 °C (212 °F); 0.749 g/cm3, 550 °C (1,022 °F);
Thermal properties
Melting temperature (Tm)	−12.6 °C (9.3 °F)
Thermal conductivity (k) at 100 °C (212 °F)	22.4 W/(m⋅K)
Specific heat capacity (c)	982 J/(kg⋅K)
Electrical properties
Surface resistivity	33.5–72.0 μΩ⋅cm
	Source

Sodium–potassium alloy, colloquially called NaK (commonly pronounced /næk/), is an alloy of two alkali metals: sodium (Na, atomic number 11) and potassium (K, atomic number 19). NaK is normally liquid at room temperature. Various commercial grades are available. NaK is highly reactive with water (like its constituent elements) and may catch fire when exposed to air, so it must be handled with special precautions.