Calcium gluconate is a calcium salt of gluconic acid. Among chemists, it is best known as an antidote for hydrofluoric acid exposure.
White powder, moderately soluble in cold water, readily soluble in hot water.
Heating causes calcium gluconate to decompose, liberating a large amount of carbon. This makes it a good candidate for a "Pharaoh's Serpent" experiment.
Availability and Uses
In some countries, such as the former Soviet bloc, calcium gluconate is available very cheaply in any drugstore in form of tablets or solutions. Tableted calcium gluconate, if it happens to be adulterated with chalk or something, can easily be purified by recrystallization through hot water. In other countries, a Russian pharmacy is a good place to start looking for it.
Its main medical use is as a calcium supplement. Chemists use it as an antidote for hydrofluoric acid poisoning, in forms of topical creamy gel or injections.
A calcium gluconate solution can be purchased from some farm and veterinary supplies, where it is intended for the treatment of milk fever. 
- Pharaoh's Snake
- Protect yourself while experimenting with hydrofluoric acid
Calcium gluconate is harmless. The medical grade salt is even safely edible as a dietary supplement.
Dry calcium gluconate or a solution thereof can be stored in any container under normal conditions.
Calcium gluconate can be disposed of into the ground or drain safely.