# Decomposition of phosphine solution in water when exposed to sunlight

Quoting from my chemistry textbook:

The solution of phosphine in water decomposes in presence of light giving red phosphorus and hydrogen gas.

I could not find any relevant details on the Internet. I wish to know the reactions behind it, and some similar examples, if any.

• What's to explain? Many things decompose under sunlight or heating, and PH3 molecule is not particularly stable. AsH3 is yet more fragile. Ever heard of Marsh test? That's an example for you. – Ivan Neretin Mar 2 '18 at 14:30
• @IvanNeretin "Many things decompose under sunlight or heating," But $\ce{NH3}$ does not, and neither does water, and probably many more chemical species that we see everyday, do they? So, I think OP's confusion is fair. Please let me know if I misinterpreted your comment. – Gaurang Tandon Apr 3 '18 at 15:43