a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar. 一种极具毒性的金属元素，有三种同素异性体，砷和砷的化合物用作除草剂、杀虫剂和各种合金，见于毒砂、雌黄、雄黄中。
