Protactinium trihydride

Protactinium trihydride is an inorganic compound with the chemical formula PaH$3$. It is isostructural with uranium trihydride and can be prepared by reacting protactinium and hydrogen at 250°C and 600 mmHg. Theoretical calculations show that it can form further compounds PaH$n$ (n = 4, 5, 8, 9) under high pressure. Protactinium trihydride is sensitive to moist air and oxygen.