Helium Elemental Symbol
Helium



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Héliu Helium Elio Hélio Helio Helium

Helium Bohr ModelHelium is a Block S, Group 18, Period 1 element. The number of electrons in each of Helium's shells is 2 and its electronic configuration is 1s2. In its elemental form helium's CAS number is 7440-59-7. The helium atom has a covalent radius of 28.pm and it's Van der Waals radius is 140.pm. Commercial helium is extracted from natural gas. Helium was discovered by Pierre Janssen and Norman Lockyer in 1868. It was first isolated by William Ramsay, Per Teodor Cleve and Abraham Langlet in 1895.

Helium is not toxic. Helium information, including technical data, safety data and its high purity properties, research, applications and other useful facts are specified below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included.


  • Properties
  • Safety Data
  • Research
  • Isotopes
  • Other Elements

Helium Properties


GENERAL PROPERTIES   PHYSICAL PROPERTIES  
Symbol: He Melting Point: -272.2 oC, -457.96 oF, 0.950 K
Atomic Number: 2 Boiling Point: -268.93 oC, -452.074 oF, 4.220 K
Atomic Weight: 4.003 Density: 120 (4.22 K) kg m-3
Element Category: noble gases Liquid Density @ Melting Point: 0.145 g·cm−3
Group, Period, Block: 18, 1, s Specific Heat: N/A
    Heat of Vaporization 0.0829 kJ·mol−1
CHEMICAL STRUCTURE Heat of Fusion 0.0138 kJ·mol−1
Electrons: 2 Thermal Conductivity: 0.1513 W·m−1·K−1
Protons: 2 Thermal Expansion: N/A
Neutrons: 2 Electrical Resistivity: N/A
Electron Configuration: 1s2 Electronegativity: N/A
Atomic Radius: N/A Tensile Strength: N/A
Covalent Radius: 28 pm Molar Heat Capacity: 5R/2 = 20.786 J·mol−1·K−1
Van der Waals radius: 140 pm Young's Modulus: N/A
Oxidation States: 0 Shear Modulus: N/A
Phase: Gas Bulk Modulus: N/A
Crystal Structure: hexagonal close-packed Poisson Ratio: N/A
Magnetic Ordering: diamagnetic Mohs Hardness: N/A
1st Ionization Energy: 2372.3 kJ·mol−1 Vickers Hardness: N/A
2nd Ionization Energy: 5250.5 kJ·mol−1 Brinell Hardness: N/A
3rd Ionization Energy: N/A Speed of Sound: 972 m·s−1
       
IDENTIFIERS   MISCELLANEOUS  
CAS Number: 7440-59-7 Abundance in typical human body, by weight: N/A
ChemSpider ID: 22423 Abundance in typical human body, by atom: N/A
PubChem CID: 23987 Abundance in universe, by weight: 230000000 ppb
MDL Number: MFCD00011031 Abundance in universe, by atom: 72000000 ppb
EC Number: 231-168-5 Discovered By: Pierre Janssen, Norman Lockyer
Beilstein Number: N/A Discovery Date: 1868
SMILES Identifier: [He]  
InChI Identifier: InChI=1S/He Other Names: Elio, Hélio
InChI Key: SWQJXJOGLNCZEY-UHFFFAOYSA-N  
       
       
       
       
       


Recent Research & Development for Helium

  • Xiao Xiao, Xueming Hua, Yixiong Wu, Comparison of temperature and composition measurement by spectroscopic methods for argon–helium arc plasma, Optics & Laser Technology, Volume 66, March 2015
  • L. Yang, F. Gao, R.J. Kurtz, X.T. Zu, Atomistic simulations of helium clustering and grain boundary reconstruction in alpha-iron, Acta Materialia, Volume 82, 1 January 2015
  • Vasilisa Veligura, Gregor Hlawacek, Raoul van Gastel, Harold J.W. Zandvliet, Bene Poelsema, Investigation of ionoluminescence of semiconductor materials using helium ion microscopy, Journal of Luminescence, Volume 157, January 2015
  • Ho Jung Lee, Injin Sah, Donghoon Kim, Hyunmyung Kim, Changheui Jang, Oxidation characteristics of the electron beam surface-treated Alloy 617 in high temperature helium environments, Journal of Nuclear Materials, Volume 456, January 2015
  • Ludwik Dabrowski, Marcin Szuta, Diffusion of helium in the perfect and non perfect uranium dioxide crystals and their local structures, Journal of Alloys and Compounds, Volume 615, 5 December 2014
  • Yu-Hao Li, Hong-Bo Zhou, Shuo Jin, Ying Zhang, Guang-Hong Lu, Strain-induced variation of electronic structure of helium in tungsten and its effects on dissolution and diffusion, Computational Materials Science, Volume 95, December 2014
  • X. Xiang, C.A. Chen, K.Z. Liu, X.L. Wang, X.C. Lai, Effect of combined doping of Fe and C on the helium behavior in Al before and after aging, Journal of Nuclear Materials, Volume 455, Issues 1–3, December 2014
  • Xuebang Wu, Xiang-Shan Kong, Yu-Wei You, C.S. Liu, Q.F. Fang, Jun-Ling Chen, G.-N. Luo, Zhiguang Wang, First principles study of helium trapping by solute elements in tungsten, Journal of Nuclear Materials, Volume 455, Issues 1–3, December 2014
  • Kotaro Ono, Mitsutaka Miyamoto, Kazuto Arakawa, Shin-ichi Matsumoto, Fumiaki Kudo, Effects of precipitated helium, deuterium or alloy elements on glissile motion of dislocation loops in Fe–9Cr–2W ferritic alloy, Journal of Nuclear Materials, Volume 455, Issues 1–3, December 2014
  • R.E. Stoller, Yu.N. Osetsky, An atomistic assessment of helium behavior in iron, Journal of Nuclear Materials, Volume 455, Issues 1–3, December 2014

Helium Isotopes


Helium has two stable isotopes: 3He and 4He.

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
3He 3.0160293191 Stable 1/2+
4He 4.0026032542 Stable 0+