Bohrium is a synthetic chemical element with the symbol Bh and atomic number 107. It is a member of the group 7 elements and is classified as a transition metal. It was first synthesized in 1981 by a team of scientists in Germany by bombarding bismuth-209 with chromium-54 ions using a heavy ion accelerator. It is a highly unstable element, with all of its isotopes being radioactive and decaying quickly. Its most stable isotope, Bohrium-270, has a half-life of only 61 seconds. Bohrium has no known uses outside of scientific research, mainly due to its high radioactivity and difficulty in producing large enough quantities for practical applications.