Does divorce occur if one of the questioner's children dies due to his wife's negligence, based on his statement to her in a fit of anger: "If one day any of my children dies because of your negligence, you are not lawful to me"?

Your statement to your wife: "If one day any of my children dies due to your negligence, you are not lawful for me," is an allusive divorce (kinayah) suspended on a condition. It does not take effect except with the intention of divorce, according to the majority of scholars. If you intended divorce with your words, then it takes effect if the condition is met. One should be cautious about being lenient with divorce pronouncements and using them in anger.