Ibn Abi Mulaykah (may Allah have mercy on him) says that he asked Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with them both) about a man who divorces his wife irrevocably (battah), then the man dies while the woman is in her iddah. Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with them both) said: Sayyiduna Abdur-Rahman bin Awf (may Allah be pleased with him) divorced Tumadir bint al-Asbagh al-Kalbiyyah (may Allah be pleased with her) irrevocably, then he died while she was in her iddah, and Sayyiduna Uthman (may Allah be pleased with him) made her an heir. Sayyiduna Ibn al-Zubayr (may Allah be pleased with them both) said: In my view, an irrevocably divorced woman does not inherit.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 15124