Neptunium Elemental Symbol
Neptunium



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Neptunium Neptunium Nettunio Neptúnio Neptunio Neptunium

Neptunium Bohr ModelNeptunium has the atomic symbol Np, atomic number 93, and atomic weight 237. It is a Block F, Group 3, Period 7 element. The number of electrons in each of Neptunium's shells is 2, 8, 18, 32, 22, 9, 2 and its electron configuration is [Rn] 5f4 6d1 7s2. The neptunium atom has a Van der Waals radius of 221.pm. In its elemental form, CAS 7439-99-8, neptunium has a silvery metallic appearance. The element was discovered by Edwin M. McMillan and P. H. Abelson in 1940. It was the first synthetic transuranium element of the actinide series discovered and was named for the planet Neptune.

Neptunium information, including technical data, safety data and its high purity properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on earth, conductivity and thermal properties are included.


  • Properties
  • Research
  • Isotopes
  • Other Elements

Neptunium Properties


GENERAL PROPERTIES   PHYSICAL PROPERTIES  
Symbol: Np Melting Point: 644 oC, 1191.2 oF, 917.15 K
Atomic Number: 93 Boiling Point: 644 oC, 1191.2 oF, 917.15 K
Atomic Weight: 237 Density: 20450 kg m-3
Element Category: Actinide Liquid Density @ Melting Point: N/A
Group, Period, Block: n/a, 7, f Specific Heat: N/A
    Heat of Vaporization 336 kJ·mol−1
CHEMICAL STRUCTURE Heat of Fusion 3.20 kJ·mol−1
Electrons: 93 Thermal Conductivity: 6.3 W·m−1·K−1
Protons: 93 Thermal Expansion: N/A
Neutrons: 144 Electrical Resistivity: (22 °C) 1.220 µΩ·m
Electron Configuration: [Rn] 5f46d17s2 Electronegativity: 1.36 (Pauling scale)
Atomic Radius: 155 pm Tensile Strength: N/A
Covalent Radius: 190±1 pm Molar Heat Capacity: 29.46 J·mol−1·K−1
Van der Waals radius: 221 pm Young's Modulus: N/A
Oxidation States: 6, 5, 4, 3 Shear Modulus: N/A
Phase: Solid  Bulk Modulus: N/A
Crystal Structure: orthorhombic Poisson Ratio: N/A
Magnetic Ordering: paramagnetic Mohs Hardness: N/A
1st Ionization Energy: 604.5 kJ·mol−1 Vickers Hardness: N/A
2nd Ionization Energy: N/A Brinell Hardness: N/A
3rd Ionization Energy: N/A Speed of Sound: N/A
       
IDENTIFIERS   MISCELLANEOUS  
CAS Number: 7439-99-8 Abundance in typical human body, by weight: N/A
ChemSpider ID: 22375 Abundance in typical human body, by atom: N/A
PubChem CID: 23933 Abundance in universe, by weight: N/A
MDL Number: N/A Abundance in universe, by atom: N/A
EC Number: N/A Discovered By: Edwin McMillan and Philip H. Abelson
Beilstein Number: N/A Discovery Date: 1940
SMILES Identifier: [Np]  
InChI Identifier: InChI=1S/Np Other Names: Nettunio
InChI Key: LFNLGNPSGWYGGD-UHFFFAOYSA-N  
       
       
       
       
       


Recent Research & Development for Neptunium

  • Chemical speciation of neptunium(VI) under strongly alkaline conditions. Structure, composition, and oxo ligand exchange. Clark DL, Conradson SD, Donohoe RJ, Gordon PL, Keogh DW, Palmer PD, Scott BL, Tait CD. Inorg Chem. 2013 Apr 1;52(7):3547-55. doi: 10.1021/ic3020139. Epub 2013 Mar 13.
  • High-temperature X-ray diffraction study of uranium-neptunium mixed oxides. Chollet M, Belin RC, Richaud JC, Reynaud M, Adenot F. Inorg Chem. 2013 Mar 4;52(5):2519-25. doi: 10.1021/ic302457m. Epub 2013 Feb 14.
  • Method for determination of neptunium in large-sized urine samples using manganese dioxide coprecipitation and 242Pu as yield tracer. Qiao J, Hou X, Roos P. Anal Chem. 2013 Feb 5;85(3):1889-95. doi: 10.1021/ac303300v. Epub 2013 Jan 16.
  • neptunium(V) sorption to goethite at attomolar to micromolar concentrations. Snow MS, Zhao P, Dai Z, Kersting AB, Zavarin M. J Colloid Interface Sci. 2013 Jan 15;390(1):176-82. doi: 10.1016/j.jcis.2012.08.058. Epub 2012 Sep 18.
  • Sensitive redox speciation of neptunium by CE-ICP-MS. Stöbener N, Amayri S, Gehl A, Kaplan U, Malecha K, Reich T. Anal Bioanal Chem. 2012 Nov;404(8):2143-50. doi: 10.1007/s00216-012-6423-7. Epub 2012 Oct 3.
  • Incorporation of neptunium(VI) into a uranyl selenite. Meredith NA, Polinski MJ, Lin J, Simonetti A, Albrecht-Schmitt TE. Inorg Chem. 2012 Oct 15;51(20):10480-2. doi: 10.1021/ic301682b. Epub 2012 Oct 2.
  • Aqueous complexation of thorium(IV), uranium(IV), neptunium(IV), plutonium(III/IV), and cerium(III/IV) with DTPA. Brown MA, Paulenova A, Gelis AV. Inorg Chem. 2012 Jul 16;51(14):7741-8. doi: 10.1021/ic300757k. Epub 2012 Jun 27.
  • neptunium multipoles and resonant x-ray Bragg diffraction by neptunium dioxide (NpO2). Lovesey SW, Detlefs C, Rodríguez-Fernández A. J Phys Condens Matter. 2012 Jun 27;24(25):256009. doi: 10.1088/0953-8984/24/25/256009.
  • Crystal and electronic structures of neptunium nitrides synthesized using a fluoride route. Silva GW, Weck PF, Kim E, Yeamans CB, Cerefice GS, Sattelberger AP, Czerwinski KR. J Am Chem Soc. 2012 Feb 15;134(6):3111-9. doi: 10.1021/ja209503n. Epub 2012 Feb 6.
  • Formation of soluble hexanuclear neptunium(IV) nanoclusters in aqueous solution: growth termination of actinide(IV) hydrous oxides by carboxylates. Takao K, Takao S, Scheinost AC, Bernhard G, Hennig C. Inorg Chem. 2012 Feb 6;51(3):1336-44. doi: 10.1021/ic201482n. Epub 2012 Jan 5.
  • New neptunium(V) borates that exhibit the alexandrite effect. Wang S, Alekseev EV, Depmeier W, Albrecht-Schmitt TE. Inorg Chem. 2012 Jan 2;51(1):7-9. doi: 10.1021/ic201682s. Epub 2011 Dec 6.
  • neptunium(III) application in extraction chromatography. Guérin N, Nadeau K, Larivière D. Talanta. 2011 Dec 15;87:8-14. doi: 10.1016/j.talanta.2011.08.062. Epub 2011 Sep 10.
  • neptunium thiophosphate chemistry: intermediate behavior between uranium and plutonium. Jin GB, Skanthakumar S, Haire RG, Soderholm L, Ibers JA. Inorg Chem. 2011 Oct 3;50(19):9688-95. doi: 10.1021/ic201493w. Epub 2011 Sep 1.
  • Role of anions and reaction conditions in the preparation of uranium(VI), neptunium(VI), and plutonium(VI) borates. Wang S, Villa EM, Diwu J, Alekseev EV, Depmeier W, Albrecht-Schmitt TE. Inorg Chem. 2011 Mar 21;50(6):2527-33. doi: 10.1021/ic102356d. Epub 2011 Feb 3.
  • High-throughput sequential injection method for simultaneous determination of plutonium and neptunium in environmental solids using macroporous anion-exchange chromatography, followed by inductively coupled plasma mass spectrometric detection. Qiao J, Hou X, Roos P, Miró M. Anal Chem. 2011 Jan 1;83(1):374-81. doi: 10.1021/ac102567b. Epub 2010 Dec 1.
  • Geomicrobiological redox cycling of the transuranic element neptunium. Law GT, Geissler A, Lloyd JR, Livens FR, Boothman C, Begg JD, Denecke MA, Rothe J, Dardenne K, Burke IT, Charnock JM, Morris K. Environ Sci Technol. 2010 Dec 1;44(23):8924-9. doi: 10.1021/es101911v. Epub 2010 Nov 3.
  • Neglected neptunium. Ibers J. Nat Chem. 2010 Nov;2(11):996. doi: 10.1038/nchem.888.
  • Boronic acid flux synthesis and crystal growth of uranium and neptunium boronates and borates: a low-temperature route to the first neptunium(V) borate. Wang S, Alekseev EV, Miller HM, Depmeier W, Albrecht-Schmitt TE. Inorg Chem. 2010 Nov 1;49(21):9755-7. doi: 10.1021/ic101678d.
  • Cerium(IV), neptunium(IV), and plutonium(IV) 1,2-phenylenediphosphonates: correlations and differences between early transuranium elements and their proposed surrogates. Diwu J, Wang S, Liao Z, Burns PC, Albrecht-Schmitt TE. Inorg Chem. 2010 Nov 1;49(21):10074-80. doi: 10.1021/ic1015912.
  • Structure determination of neptunium(VI) mu3-hydroxobenzoate, [(NpO2)2(mu3-OH)2(H5C6COO)2] x 2 H2O. Charushnikova IA, Krot NN, Makarenkov VI. Inorg Chem. 2010 Sep 6;49(17):7611-3. doi: 10.1021/ic100951y.

Neptunium Isotopes


Neptunium is an artificial element. It has no stable isotopes.