| The total amount of astatine present in the earth's crust, however, is probably less than 1 oz. |
| By one estimate, no more than a millionth of a gram of astatine has ever been produced in the lab. |
| The halogens are a group of chemical elements that includes fluorine, chlorine, bromine, iodine, and astatine. |
| The bismuth target is cooled during irradiation to prevent the volatile astatine disappearing. |
| I've updated the Periodic Table entries for the halogen astatine and for darmstadtium, which you may know better as element 110 or ununnilium. |
| This, together with its short lifetime, leaves no reason for considering the effects of astatine on human health. |
