Sodium mercury amalgams containing less than 3% Na are not too sensitive to
air; however they must be stored in an air-free atmosphere. Complete liquefaction occurs at the following (liquidus) temperatures:
0.5% Na, O°Cj 1.0% Na, 50°C; 1.5% Na, 100°C; 2.0% Na, 130°C;
2.5% Na, 156°C; 3% Na, 250°C; 4.0% Na, 320°C.
Clean sodium metal (11.5 g.) is cut into 5-mm. cubes. The cubes
a r e speared with a pointed glass rod and rapidly introduced below
the surface of warm (30-40°C) pure mercury (1150 g. = 85 ml.)
contained in a 500-ml. wide-neck Erlenmeyer flask. The flask is
covered with cardboard to prevent spattering during the rather
vigorous amalgam formation reaction.
