Curium

Curium is a synthetic chemical element in the periodic table that has the atomic number 96. It has the chemical symbol Cm and it is a radioactive metal. In chemistry it is placed in a group of metal elements named the actinides. Curium is a transuranic element. It is a radioactive element that does not exist in nature. Curium has a silver color and it is made by bombarding a plutonium target with alpha particles (helium ions). Curium was named after Marie Curie and her husband Pierre.

Curium,  ₉₆Cm

General properties
Pronunciation	/ˈkjʊəriəm/ ​(KEWR-ee-əm)
Appearance	silvery metallic, glows purple in the dark
Mass number	247 (most stable isotope)
Curium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Gd ↑ Cm ↓ (Upn) americium ← curium → berkelium
Atomic number (Z)	96
Group	group n/a
Period	period 7
Block	f-block
Element category	actinide
Electron configuration	[Rn] 5f7 6d1 7s2
Electrons per shell	2, 8, 18, 32, 25, 9, 2
Physical properties
Phase at STP	Cm: Solid
Melting point	1613 K ​(1340 °C, ​2444 °F)
Boiling point	3383 K ​(3110 °C, ​5630 °F)
Density (near r.t.)	13.51 g/cm3
Heat of fusion	13.85 kJ/mol
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1788 1982
Atomic properties
Oxidation states	+2, +3, +4, +5, +6, (an amphoteric oxide)
Electronegativity	Pauling scale: 1.3
Ionization energies	1st: 581 kJ/mol
Atomic radius	empirical: 174 pm
Covalent radius	169±3 pm
Spectral lines of curium
Other properties
Natural occurrence	Cm: Synthetic
Crystal structure	​double hexagonal close-packed (dhcp)
Electrical resistivity	1.25 µΩ·m
Magnetic ordering	antiferromagnetic-paramagnetic transition at 52 K
CAS Number	7440-51-9
History
Naming	named after Marie Skłodowska-Curie and Pierre Curie
Discovery	Glenn T. Seaborg, Ralph A. James, Albert Ghiorso (1944)
Main isotopes of curium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 242Cm syn 160 d SF – α 238Pu 243Cm syn 29.1 y α 6.169 239Pu ε 0.009 243Am SF – – 244Cm syn 18.1 y SF – α 240Pu 245Cm syn 8500 y SF – α 241Pu 246Cm syn 4730 y α 242Pu SF – 247Cm syn 1.56×107 y α 243Pu 248Cm syn 3.40×105 y α 244Pu SF – 250Cm syn 9000 y SF – – α 5.169 246Pu β− 0.037 250Bk

Uses

Curium is used currently in rovers and space machinery.

Pierre and Marie Curie.

Curium Media

• 

  Physicist Glenn T. Seaborg, atomic pioneer and Commissioner of the Atomic Energy Commission., ca. 1964

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  The 60-inch (150 cm) cyclotron at the Lawrence Radiation Laboratory, University of California, Berkeley, in August 1939.

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  Double-hexagonal close packing with the layer sequence ABAC in the crystal structure of α-curium (A: green, B: blue, C: red)

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  Photoluminescence of the Cm(HDPA)3·H2O crystal upon irradiation with 420 nm light

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  A solution of Curium-248

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  Transmutation flow between 238Pu and 244Cm in LWR.Fission percentage is 100 minus shown percentages.Total rate of transmutation varies greatly by nuclide.245Cm–248Cm are long-lived with negligible decay.

• 

  Several isotopes of curium were detected in the fallout from the Ivy Mike nuclear test.

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  Chromatographic elution curves revealing the similarity between Tb, Gd, Eu lanthanides and corresponding Bk, Cm, Am actinides.

• 

  Predicted curocene structure