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Americium is a synthetic radioactive chemical element with the symbol Am and atomic number 95. It is a transuranic member of the actinide series, in the periodic table located under the lanthanide element europium, and thus by analogy was named after the Americas.
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.
Curium is a transuranic, radioactive chemical element with the symbol Cm and atomic number 96. This actinide element was named after eminent scientists Marie and Pierre Curie, both known for their research on radioactivity. Curium was first intentionally made by the team of Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso in 1944, using the cyclotron at Berkeley. They bombarded the newly discovered element plutonium with alpha particles. This was then sent to the Metallurgical Laboratory at University of Chicago where a tiny sample of curium was eventually separated and identified. The discovery was kept secret until after the end of World War II. The news was released to the public in November 1947. Most curium is produced by bombarding uranium or plutonium with neutrons in nuclear reactors – one tonne of spent nuclear fuel contains ~20 grams of curium.
Neptunium is a chemical element with the symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons. Neptunium metal is silvery and tarnishes when exposed to air. The element occurs in three allotropic forms and it normally exhibits five oxidation states, ranging from +3 to +7. It is radioactive, poisonous, pyrophoric, and capable of accumulating in bones, which makes the handling of neptunium dangerous.
In crystallography, the cubiccrystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals.
Calcium disilicide (CaSi2) is an inorganic compound, a silicide of calcium. It is a whitish or dark grey to black solid matter with melting point 1033 °C. It is insoluble in water, but may decompose when subjected to moisture, evolving hydrogen and producing calcium hydroxide. It decomposes in hot water, and is flammable and may ignite spontaneously in air.
Plutonium hexafluoride is the highest fluoride of plutonium, and is of interest for laser enrichment of plutonium, in particular for the production of pure plutonium-239 from irradiated uranium. This pure plutonium is needed to avoid premature ignition of low-mass nuclear weapon designs by neutrons produced by spontaneous fission of plutonium-240.
Chromium(III) boride, also known as chromium monoboride (CrB), is an inorganic compound with the chemical formula CrB. It is one of the six stable binary borides of chromium, which also include Cr2B, Cr5B3, Cr3B4, CrB2, and CrB4. Like many other transition metal borides, it is extremely hard (21-23 GPa), has high strength (690 MPa bending strength), conducts heat and electricity as well as many metallic alloys, and has a high melting point (~2100 °C). Unlike pure chromium, CrB is known to be a paramagnetic, with a magnetic susceptibility that is only weakly dependent on temperature. Due to these properties, among others, CrB has been considered as a candidate material for wear resistant coatings and high-temperature diffusion barriers.
Werner Urland is a German chemist whose name is imprinted in the pioneering implementation of the Angular Overlap Model for the interpretation of optical and magnetic properties of rare-earth coordination compounds. This approach receives a renewed value in the context of the vogue around the lanthanide-based new materials, such as achieving magnets at molecular scale, or designing new phosphor materials.
Plutonocene, Pu(C8H8)2, is an organoplutonium compound composed of a plutonium atom sandwiched between two cyclooctatetraenide (COT2-) rings. It is a dark red, very air-sensitive solid that is sparingly soluble in toluene and chlorocarbons. Plutonocene is a member of the actinocene family of metallocenes incorporating actinide elements in the +4 oxidation state.
The telluride iodides are chemical compounds that contain both telluride ions (Te2−) and iodide ions (I−). They are in the class of mixed anion compounds or chalcogenide halides.
Plutonium selenide is a binary inorganic compound of plutonium and selenium with the chemical formula PuSe. The compound forms black crystals and does not dissolve in water.
Plutonium silicide is a binary inorganic compound of plutonium and silicon with the chemical formula PuSi. The compound forms gray crystals.
Plutonium (IV) nitrate is an inorganic compound, a salt of plutonium and nitric acid with the chemical formula Pu(NO3)4. The compound dissolves in water and forms crystalline hydrates as dark green crystals.
Curium compounds are compounds containing the element curium (Cm). Curium usually forms compounds in the +3 oxidation state, although compounds with curium in the +4, +5 and +6 oxidation states are also known.
Plutonium phosphide is a binary inorganic compound of plutonium and phosphorus with the formula PuP.
Phosphide bromides or bromide phosphides are compounds containing anions composed of bromide (Br−) and phosphide (P3−) anions. Usually phosphorus is covalently connected into more complex structures. They can be considered as mixed anion compounds. They are in the category of pnictidehalides. Related compounds include the phosphide chlorides, phosphide iodides, nitride bromides, arsenide bromides, and antimonide bromides.
Samarium compounds are compounds formed by the lanthanide metal samarium (Sm). In these compounds, samarium generally exhibits the +3 oxidation state, such as SmCl3, Sm(NO3)3 and Sm(C2O4)3. Compounds with samarium in the +2 oxidation state are also known, for example SmI2.
Neptunium compounds are compounds containg the element neptunium (Np). Neptunium has five ionic oxidation states ranging from +3 to +7 when forming chemical compounds, which can be simultaneously observed in solutions. It is the heaviest actinide that can lose all its valence electrons in a stable compound. The most stable state in solution is +5, but the valence +4 is preferred in solid neptunium compounds. Neptunium metal is very reactive. Ions of neptunium are prone to hydrolysis and formation of coordination compounds.
Americium compounds are compounds containing the element americium (Am). These compounds can form in the +2, +3 and +4, although the +3 oxidation state is the most common. The +5, +6 and +7 oxidation states have also been reported.
References
- ↑ Morss, L. R.; Edelstein, Norman M.; Fuger, Jean (31 December 2007). The Chemistry of the Actinide and Transactinide Elements (3rd ed., Volumes 1-5). Springer Science & Business Media. p. 1022. ISBN 978-1-4020-3598-2 . Retrieved 11 January 2022.
- ↑ NBS Monograph. National Bureau of Standards. 1959. p. 65. Retrieved 11 January 2022.
- ↑ Gorum, A. E. (10 February 1957). "The crystal structures of PuAs, PuTe, PuP and PuOSe". Acta Crystallographica . 10 (2): 144. doi:10.1107/S0365110X5700047X . Retrieved 11 January 2022.
- ↑ Dabos-Seignon, S.; Benedict, U.; Spirlet, J. C.; Pages, M. (15 July 1989). "Compression studies on PuAs up to 45 GPa". Journal of the Less Common Metals . 153 (1): 133–141. doi:10.1016/0022-5088(89)90539-0. ISSN 0022-5088 . Retrieved 11 January 2022.
- ↑ Blaise, A.; Fournier, J. M.; Salmon, P. (1 September 1973). "Magnetic properties of plutonium monoarsenide". Solid State Communications . 13 (5): 555–557. Bibcode:1973SSCom..13..555B. doi:10.1016/S0038-1098(73)80012-2. ISSN 0038-1098 . Retrieved 11 January 2022.