Tetraphosphorus decoxide is a pyro-technic composition with the chemical formula P4O10.
It is used for industrial purposes like providing heat or as an oxidizing agent. The flakes are colorless and highly toxic when inhaled.
Its dangerous nature can make it be mistaken for sugar, which further leads to its toxicity.
Pentaphosphorous acid oxidation produces P2O5, not tetraphosphorus decoxide!
Examples include ammonium nitrate (NH4NO3) and potassium permanganate (KMnO4). The latter was famously misused in the case of Karen Wetterhahn who has died of manganese poisoning after contact with this substance.
The reaction of P4O10 and water:
P4O10 + 6H2O → 4HPO3OH + 5H3PO4
Only on contact with moisture, tetraphosphorus decoxide will give off poisonous phosphorous oxides. The compound melts at 77°C/170°F into a colorless liquid corrosive to the eyes, respiratory system and skin.
Tetraphosphorus decoxide can be mistaken for sugar by workers at a warehouse who have subsequently fallen ill, according to an article in The Hutchinson News .
Though it may seem hard to believe that anyone could mistake this for sugar, there are many reports about people mistaking antifreeze for a soft drink, or laundry detergent for candy.