Protactinium

Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states. The average concentrations of protactinium in the Earth's crust is typically on the order of a few parts per trillion, but may reach up to a few parts per million in some uraninite ore deposits. Because of its scarcity, high radioactivity and high toxicity, there are currently no uses for protactinium outside of scientific research, and for this purpose, protactinium is mostly extracted from spent nuclear fuel.

Protactinium was first identified in 1913 by Kasimir Fajans and Oswald Helmuth Göhring and named brevium because of the short half-life of the specific isotope studied, namely protactinium-234. A more stable isotope (²³¹Pa) of protactinium was discovered in 1917/18 by Otto Hahn and Lise Meitner, and they chose the name proto-actinium, but then the IUPAC named it finally protactinium in 1949 and confirmed Hahn and Meitner as discoverers. The new name meant "parent of actinium" and reflected the fact that actinium is a product of radioactive decay of protactinium. It is noted that John Arnold Cranston (working with Frederick Soddy) is also credited with discovering the stable isotope in 1915 but delayed his announcement due to being called up for service in the First World War.

Uranium

Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-white metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all its isotopes are unstable (with half-lives of the six naturally known isotopes, uranium-233 to uranium-238, varying between 69 years and 4.5 billion years). The most common isotopes of uranium are uranium-238 (which has 146 neutrons and accounts for almost 99.3% of the uranium found in nature) and uranium-235 (which has 143 neutrons, accounting for 0.7% of the element found naturally). Uranium has the second highest atomic weight of the primordially occurring elements, lighter only than plutonium. Its density is about 70% higher than that of lead, but slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.

Bikstok Røgsystem

Bikstok Røgsystem is a Danish dancehall band consisting of Eaggerman (Dwayne McFarlane), Pharfar (Søren Schou) and Blæs Bukki (Lasse Bavngaard). The band is one of the first to perform reggae and dancehall in Danish.

Their debut and only album Over stok og sten was very successful, received very favourable reviews, and entered the Danish album chart as number one in February and made Gold by June 2005.

From 2006 until 2012, the group have been more or less disbanded, but it still occasionally reunited for one-off performances.

From 2013 they got together in a reunion to prepare a new album. The result was the 2015 album Uranium with the album being credited to Bikstok rather than the full name Bikstok Røgsystem.

Discography

Albums

Singles

References

External links

Uranium (disambiguation)

Uranium may refer to:

Chemistry

Places

Arts

See also