What is the waiting period (iddah) for a woman divorced before consummating the marriage, and what is the ruling concerning a woman whose husband died before consummating the marriage?

A woman divorced before consummation has no waiting period ('iddah) according to the consensus of scholars, based on the Almighty's saying: "O you who have believed, when you marry believing women and then divorce them before you have touched them, then there is not for you any waiting period to count concerning them." As for a widow, she must observe the waiting period, even if her husband died before consummation, due to the generality of the Almighty's saying: "And those of you who die and leave wives behind them, they (the wives) shall wait (as regards their marriage) for four months and ten days." This is also based on the ruling of the Messenger of Allah, peace be upon him, regarding Burda' bint Washik.