Radium bromide Institute had four grams of radium total, which at the time was more than half the world supply. Countries all over the world set out to make as much radium as possible, a time consuming and expensive task. It was reported in "Science" magazine in 1919 that the United States had produced approximately 55 grams of radium since 1913, which was also more than half the radium produced in the world at the time. A principal source for radium is pitchblende, which holds a total of 257 mg of radium per ton of UO. Obviously with so little product recovered
Radium this scheme, Ra was named actinium X (AcX), Ra thorium X (ThX), Ra radium (Ra), and Ra mesothorium 1 (MsTh). When it was realized that all of these are isotopes of the same element, many of these names fell out of use, and "radium" came to refer to all isotopes, not just Ra. Some of radium-226's decay products received historical names including "radium", ranging from radium A to radium G, with the letter indicating approximately how far they were down the chain from their parent Ra. Ra is the most stable isotope of radium and is the last isotope in