Reference: Fataawa at-Talaaq – Question 11, Page 25
Question: I divorced my wife whilst I was in a state of extreme anger, so I said to her: “You are divorced, divorced”, twice. So does this constitute a divorce or not? [Kindly] enlighten me [and] may Allaah reward you with good.
Response: If the anger was extreme, and there were clear reasons [for this anger] such as beating each other or verbally abusing each other, then divorce does not occur whilst in a state of extreme anger, according to the most correct of the two opinions of the scholars. This is because the one who is extremely angry does not understand the harmful effect[s] of divorce and does not realise this [at the time], so he is similar to one who is deranged and mad. So [the declaration of] this divorce is incorrect.
However, if the anger was mild, or there were unacceptable reasons [for this anger], then this case would not be heard [by a judge], and therefore [the declaration of] divorce is applicable.