Dubnium is a synthetic element with the symbol Db and atomic number 105. It was first discovered in the 1970s by scientists in both the United States and the Soviet Union. Dubnium is classified as a transition metal and is part of the d-block of the periodic table. Due to its instability and short half-life, Dubnium does not occur naturally and must be created in a laboratory. It is primarily produced through nuclear reactions involving heavy elements. The most stable isotope, Db-268, has a half-life of about 29 hours, making it challenging to study its properties extensively.