# What are the conditions for nuclear decay?

I read something about that the Q-Value hast to be greater then $$0$$.
But there must be certainly more conditions otherwise there would be nuclei that could't decay.

• And you have not been able to think of a nucleus that does not decay? – Pieter Jul 13 at 10:13
• A positive Q-value is mandatory if you want energy to be conserved, so no matter if other conditions (such as angular momentum, parity, barionic number and charge conservation) are met, nuclei are stable under decays with negative Q. – Francesco Arnaudo Jul 13 at 10:50