మూస:నెప్ట్యునియం మూలకము

Neptunium, 00Np
Neptunium
Pronunciation/nɛpˈtjniəm/ (nep-TEW-nee-əm)
Appearancesilvery metallic
Mass number[237]
Neptunium 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 Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
Pm

Np

(Uqp)
uraniumneptuniumplutonium
Groupమూస:Infobox element/symbol-to-group/format
Periodperiod 7
Block  f-block
Electron configuration[Rn] 5f4 6d1 7s2
Electrons per shell2, 8, 18, 32, 22, 9, 2
Physical properties
Phase at STPsolid
Melting point912±3 K ​(639±3 °C, ​1182±5 °F)
Boiling point4447 K ​(4174 °C, ​7545 °F) (extrapolated)
Density (near r.t.)alpha: 20.45 g/cm3[1]
accepted standard value: 19.38 g/cm3
Heat of fusion5.19 kJ/mol
Heat of vaporization336 kJ/mol
Molar heat capacity29.46 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2194 2437
Atomic properties
Oxidation states+2, +3, +4,[2] +5, +6, +7 (an amphoteric oxide)
ElectronegativityPauling scale: 1.36
Ionization energies
  • 1st: 604.5 kJ/mol
Atomic radiusempirical: 155 pm
Covalent radius190±1 pm
Color lines in a spectral range
Spectral lines of neptunium
Other properties
Natural occurrencefrom decay
Crystal structureorthorhombic
Orthorhombic crystal structure for neptunium
Thermal conductivity6.3 W/(m⋅K)
Electrical resistivity1.220 µΩ⋅m (22 °C)
Magnetic orderingparamagnetic[3]
CAS Number7439-99-8
History
Namingafter planet Neptune, itself named after Roman god of the sea Neptune
DiscoveryEdwin McMillan and Philip H. Abelson (1940)
Isotopes of neptunium
Template:infobox neptunium isotopes does not exist
 Category: Neptunium
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References

  1. Sanchez, Rene G.; Loaiza, David J.; Kimpland, Robert H.; Hayes, David K.; Cappiello, Charlene C.; Myers, William L.; Jaegers, Peter J.; Clement, Steven D.; Butterfield, Kenneth B. "Criticality of a 237Np Sphere" (PDF). Japanese Atomic Energy Agency. Retrieved 2014-08-06. {{cite web}}: Invalid |display-authors=9 (help)
  2. Np(II), (III) and (IV) have been observed, see Dutkiewicz, Michał S.; Apostolidis, Christos; Walter, Olaf; Arnold, Polly L (2017). "Reduction chemistry of neptunium cyclopentadienide complexes: from structure to understanding". Chem. Sci. 8 (4): 2553–2561. doi:10.1039/C7SC00034K. PMC 5431675. PMID 28553487.
  3. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.