What is the ruling on divorce if it occurs while the wife is in a state of purity during which her husband had intercourse with her? And does "intercourse during a period of purity in which he had intercourse with her" mean intercourse on the same day as the divorce, or after the completion of her menstrual cycle?

Divorce, pronounced in anger, is valid as long as the one uttering it is aware of what he is saying. The phrase "You are divorced" is an explicit statement that unequivocally effects divorce. Repeating "You are divorced" with the intention of emphasis counts as a single divorce. Divorcing one's wife during a period of purity in which he had intercourse with her is an innovated divorce ( Talaq Bid'i ), but it is valid according to the majority of scholars, and this is the most preponderant and adopted opinion for fatwa. Divorcing her during a period of purity in which he had intercourse means that the divorce occurs after the husband has had intercourse with his wife during that period of purity; it is not a condition that the divorce occur on the same day as the intercourse.