Berkelium is a transuranic radioactive chemical element with the symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the Lawrence Berkeley National Laboratory where it was discovered in December 1949. Berkelium was the fifth transuranium element discovered after neptunium, plutonium, curium and americium.
Californium is a radioactive chemical element with the symbol Cf and atomic number 98. The element was first synthesized in 1950 at Lawrence Berkeley National Laboratory, by bombarding curium with alpha particles. It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all elements that have been produced in amounts large enough to see with the naked eye. The element was named after the university and the U.S. state of California.
Selenoyl fluoride, selenoyl difluoride, selenium oxyfluoride, or selenium dioxydifluoride is a chemical compound with the formula SeO2F2.
Few compounds of californium have been made and studied. The only californium ion that is stable in aqueous solutions is the californium(III) cation. The other two oxidation states are IV (strong oxidizing agents) and II (strong reducing agents). The element forms a water-soluble chloride, nitrate, perchlorate, and sulfate and is precipitated as a fluoride, oxalate or hydroxide. If problems of availability of the element could be overcome, then CfBr2 and CfI2 would likely be stable.
Berkelium forms a number of chemical compounds, where it normally exists in an oxidation state of +3 or +4, and behaves similarly to its lanthanide analogue, terbium. Like all actinides, berkelium easily dissolves in various aqueous inorganic acids, liberating gaseous hydrogen and converting into the trivalent oxidation state. This trivalent state is the most stable, especially in aqueous solutions, but tetravalent berkelium compounds are also known. The existence of divalent berkelium salts is uncertain and has only been reported in mixed lanthanum chloride-strontium chloride melts. Aqueous solutions of Bk3+ ions are green in most acids. The color of the Bk4+ ions is yellow in hydrochloric acid and orange-yellow in sulfuric acid. Berkelium does not react rapidly with oxygen at room temperature, possibly due to the formation of a protective oxide surface layer; however, it reacts with molten metals, hydrogen, halogens, chalcogens and pnictogens to form various binary compounds. Berkelium can also form several organometallic compounds.
Californium oxychloride (CfOCl) is a radioactive salt first discovered in measurable quantities in 1960. It is composed of a single californium cation and oxychloride consisting of one chloride and one oxide anion. It was the first californium compound ever isolated.
Californium polyborate is a covalent compound with formula Cf[B6O8(OH)5]. In this compound the californium is in a +3 oxidation state.
Actinium(III) fluoride (AcF3) is an inorganic compound, a salt of actinium and fluorine.
Mixed-anion compounds, heteroanionic materials or mixed-anion materials are chemical compounds containing cations and more than one kind of anion. The compounds contain a single phase, rather than just a mixture.
Californium(III) chloride is an inorganic compound with a chemical formula CfCl3. Like in californium oxide (Cf2O3) and other californium halides, including californium fluoride (CfF3) and iodide (CfI3), the californium atom has an oxidation state of +3.
Californium(III) bromide is an inorganic compound, a salt with a chemical formula CfBr3. Like in californium oxide (Cf2O3) and other californium halides, including californium(III) fluoride (CfF3), californium(III) chloride, and californium(III) iodide (CfI3), the californium atom has an oxidation state of +3.
Berkelium(IV) oxide, also known as berkelium dioxide, is a chemical compound with the formula BkO2. This compound slowly decays to californium(IV) oxide. It can be converted to berkelium(III) oxide by hydrogen reduction at 600 °C.
Einsteinium compounds are compounds that contain the element einsteinium (Es). These compounds largely have einsteinium in the +3 oxidation state, or in some cases in the +2 and +4 oxidation states. Although einsteinium is relatively stable, with half-lives ranging from 20 days upwards, these compounds have not been studied in great detail.
Berkelium(III) chloride also known as berkelium trichloride, is a chemical compound with the formula BkCl3. It is a water-soluble green salt with a melting point of 603 °C. This compound forms the hexahydrate, BkCl3·6H2O.
Californium(III) fluoride is a binary inorganic compound of californium and fluorine with the formula CfF
3
Californium(III) oxide is a binary inorganic compound of californium and oxygen with the formula Cf
2O
3. It is one of the first obtained solid compounds of californium, synthesized in 1958.
Californium(IV) oxide is a binary inorganic compound of californium and oxygen with the formula CfO
2.
Californium(II) iodide is a binary inorganic compound of californium and iodine with the formula CfI
2.
Californium(III) iodide is a binary inorganic compound of californium and iodine with the formula CfI
3.
Californium(III) oxyiodide is a inorganic compound of californium, iodine, and oxygen with the formula CfOI.
