Thulium is element 69 on the periodic table with 100 neutrons, 69 protons, and 69 electrons. The Swedish chemist Per Teodor Cleve discovered Thulium by extracting it from Erbium in 1879 at the University of Uppsala, Sweden. Since thulium is expensive, it is not practical for any use. On the other hand, if we ignore the price, thulium is good as an energy source, in microwaves, a radiation source in x-rays, and for doping Something interesting about fiber lasers. The only threat of thulium is to humans. Thulium is highly toxic to humans and the metal dust is flammable and can cause poisoning.An intresting fact is you can cut through thulium with a knife. In conclusion, Per Teodor Cleve discovered thulium in Sweden, too expensive for practical
