3,5,4 Boiling point 550 Stable isotopes 1 Heat of vapor. In this solid form it maintains its P4 molecules. White phosphorus is metastable and slowly changes to a stable form, red phosporus, in the presence of light or upon heating.
Red phosphorus is far more stable than the white form.
Red phosphorus cannot be converted into white phosphorus except by vaporizing it. White phosphorus is very poisonous, a lethal dose being about 0.15 grams. It causes necrosis of the bones, especially those of the jaw. Red phosphorus is not poisonous. Hydroxyapatite is the main constituent of teeth and bones.