Neptunium, 93Np
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 Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Pm

Np

uraniumneptuniumplutonium
Atomic number (Z)93
Groupf-block groups (no number)
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 (at 20° C)20.48 g/cm3 (237Np)[1]
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 statescommon: +5
+2,? +3,[2] +4,[3] +6,[2] +7[2]
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 (oP8)
Lattice constants
Orthorhombic crystal structure for neptunium
a = 472.3 pm
b = 488.7 pm
c = 666.3 pm (at 20 °C)[1]
Thermal conductivity6.3 W/(m⋅K)
Electrical resistivity1.220 µΩ⋅m (at 22 °C)
Magnetic orderingparamagnetic[4]
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
Main isotopes[5] Decay
abun­dance half-life (t1/2) mode pro­duct
235Np synth 396.1 d α 231Pa
ε 235U
236Np synth 1.54×105 y ε 236U
β 236Pu
α 232Pa
237Np trace 2.144×106 y α 233Pa
239Np trace 2.356 d β 239Pu
 Category: Neptunium
| references
Np · Neptunium
U ←

ibox U

iso
93
Np  [e]
IB-Np [e]
IBisos [e]
→ Pu

ibox Pu

indexes by PT (page)
child table, as reused in {IB-Np}
Main isotopes of neptunium
Main isotopes[5] Decay
abun­dance half-life (t1/2) mode pro­duct
235Np synth 396.1 d α 231Pa
ε 235U
236Np synth 1.54×105 y ε 236U
β 236Pu
α 232Pa
237Np trace 2.144×106 y α 233Pa
239Np trace 2.356 d β 239Pu
Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
  most stable isotope
Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01)
See also {{Index of data sets}} · Cat:data sets (46) · (this table: )

References

  1. ^ a b Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  2. ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
  3. ^ 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.
  4. ^ Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.
  5. ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.