Crystallization of super cooled liquid sodium acetate trihydrate
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WARNING - experimenter should become familiar with the properties and
handling of materials described before proceeding.

A glass cylinder (1-2 liter size) containing about 2/3 capacity of solid
sodium acetate trihydrate is heated to about 90 C. in a water bath.

To this, add carefully with stirring only enough water, if needed, to
produce a clear solution.

To reduce the chance of spontaneous crystallization - while still hot,
using a wash bottle of water, carefully rinse the inside walls of the
cylinder with minimum disturbance of the liquid surface. Use only a few ml
of water. This will provide a dilute layer at the surface, which can
tolerate some disturbance, dust, or seeding. A small disadvantage is that
very small seed particles might float on top, preventing crystallization
at the intended time, but this is seldom a problem and easily remedied.

Cover with a very clean watch glass, seal the edges with lab film, and
allow to cool slowly - overnight.

Handle the cylinder carefully when at room temperature to reduce the
change of spontaneous crystallization. Crystallization can occur without
an apparent cause, but if handled carefully, with some luck,
crystallization will not occur until the liquid is seeded with a crystal
of sodium acetate trihydrate.

The crystallization process is exothermic - expect a final temperature
that is somewhat uncomfortable to the touch.

There is no need to dispose of the material, as it can be used repeatedly.

Duplicate batches are recommended in case of unintended crystallization.

LCM 20040406