Does divorce occur if a man tells his wife, "If you open your mouth, you are divorced," and then she speaks about the same subject hours later?

If your intention by preventing your wife from arguing with you was to prevent her absolutely, then a divorce has occurred. This is the saying of the majority of scholars. However, according to Ibn Taymiyyah, no divorce occurs, but you are obliged to offer an expiation for breaking an oath (kaffarat yameen). As for if your intention was to prevent her temporarily, and she remained silent at that time, then you have not broken your oath, no divorce occurs, and you are not obliged to offer an expiation for breaking an oath.