Helium Elemental Symbol

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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

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
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

Recent Research & Development for Helium

  • Does helium act on vascular endothelial function in humans? Kinoshita H, Hatakeyama N, Fujiwara Y. Anesthesiology. 2013 Aug;119(2):488. doi: 10.1097/ALN.0b013e3182987cd2. No abstract available.
  • The interaction of a nanoscale coherent helium-ion probe with a crystal. D'Alfonso AJ, Forbes BD, Allen LJ. Ultramicroscopy. 2013 Jul 3. doi:pii: S0304-3991(13)00162-9. 10.1016/j.ultramic.2013.06.019. [Epub ahead of print]
  • Diagnostic potential of the pulsed discharged helium ionization detector (PDHID) for pathogenic Mycobacterial volatile biomarkers. Manginell RP, Pimentel AS, Mowry CD, Mangan MA, Moorman MW, Allen A, Schares ES, Achyuthan KE. J Breath Res. 2013 Jul 18;7(3):037107. [Epub ahead of print]
  • Ejection of quasi-free-electron pairs from the helium-atom ground state by single-photon absorption. Schöffler MS, Stuck C, Waitz M, Trinter F, Jahnke T, Lenz U, Jones M, Belkacem A, Landers AL, Pindzola MS, Cocke CL, Colgan J, Kheifets A, Bray I, Schmidt-Böcking H, Dörner R, Weber T. Phys Rev Lett. 2013 Jul 5;111(1):013003. Epub 2013 Jul 2.
  • Precision frequency metrology of helium 2^{1}s_{0}?2^{1}p_{1} transition. Luo PL, Peng JL, Shy JT, Wang LB. Phys Rev Lett. 2013 Jul 5;111(1):013002. Epub 2013 Jul 1.
  • Ultrastructural analysis of wild type and mutant Drosophila melanogaster using helium ion microscopy. Boseman A, Nowlin K, Ashraf S, Yang J, Lajeunesse D. Micron. 2013 Jun 24. doi:pii: S0968-4328(13)00088-7. 10.1016/j.micron.2013.06.005. [Epub ahead of print]
  • Effects of pneumoperitoneum with carbon dioxide and helium on renal function and morphology in rats. Freitas PF, Durães LC, Carvalho FA, Duarte SA, Carneiro FP, Sousa JB. Acta Cir Bras. 2013 Jul;28(7):494-8.
  • An apparatus for pulsed ESR and DNP experiments using optically excited triplet states down to liquid helium temperatures. Eichhorn TR, Haag M, van den Brandt B, Hautle P, Wenckebach WT, Jannin S, van der Klink JJ, Comment A. J Magn Reson. 2013 Jun 22;234C:58-66. doi: 10.1016/j.jmr.2013.06.009. [Epub ahead of print]
  • Microsolvation in superfluid helium droplets studied by the electronic spectra of six porphyrin derivatives and one chlorine compound. Riechers R, Pentlehner D, Slenczka A. J Chem Phys. 2013 Jun 28;138(24):244303. doi: 10.1063/1.4811199.
  • High resolution electron microscopy of Ag-clusters in crystalline and non-crystalline morphologies grown inside superfluid helium nanodroplets. Volk A, Thaler P, Koch M, Fisslthaler E, Grogger W, Ernst WE. J Chem Phys. 2013 Jun 7;138(21):214312. doi: 10.1063/1.4807843.
  • Dynamics of vortex assisted metal condensation in superfluid helium. Popov E, Mammetkuliyev M, Eloranta J. J Chem Phys. 2013 May 28;138(20):204307. doi: 10.1063/1.4807382.
  • Solubility of Helium in Ice Ih at Pressures up to 2000 bar: Experiment and Calculations. Ildyakov AV, Manakov AY, Aladko EY, Kosyakov VI, Shestakov VA. J Phys Chem B. 2013 Jun 27;117(25):7756-62. doi: 10.1021/jp400985w. Epub 2013 Jun 14.
  • High-resolution, high-throughput, positive-tone patterning of poly(ethylene glycol) by helium beam exposure through stencil masks. Cacao EE, Nasrullah A, Sherlock T, Kemper S, Kourentzi K, Ruchhoeft P, Stein GE, Willson RC. PLoS One. 2013 May 24;8(5):e56835. doi: 10.1371/journal.pone.0056835. Print 2013.
  • The ethyl radical in superfluid helium nanodroplets: rovibrational spectroscopy and ab initio computations. Raston PL, Agarwal J, Turney JM, Schaefer HF 3rd, Douberly GE. J Chem Phys. 2013 May 21;138(19):194303. doi: 10.1063/1.4804435.
  • Spin-orbit suppression of cold inelastic collisions of aluminum and helium. Connolly CB, Au YS, Chae E, Tscherbul TV, Buchachenko AA, Lu HI, Ketterle W, Doyle JM. Phys Rev Lett. 2013 Apr 26;110(17):173202. Epub 2013 Apr 23.
  • A miniaturised electron ionisation time-of-flight mass spectrometer that uses a unique helium ion removal pulsing technique specifically for gas analysis. Qing J, Huang Z, Zhang Y, Zhu H, Tan G, Gao W, Yang PY. Analyst. 2013 Jun 21;138(12):3394-401. doi: 10.1039/c3an00217a. Epub 2013 May 13.
  • Comparison of Lung Clearance Index Measured During Helium Washin and Washout in Children With Cystic Fibrosis. Vermeulen F, Ophoff J, Proesmans M, De Boeck K. Pediatr Pulmonol. 2013 May 9. doi: 10.1002/ppul.22719. [Epub ahead of print]
  • US bill would keep helium store afloat. Peplow M. Nature. 2013 May 9;497(7448):168-9. doi: 10.1038/497168a. No abstract available.
  • High-precision alignment of electron tomography tilt series using markers formed in helium-ion microscope. Hayashida M, Iijima T, Tsukahara M, Ogawa S. Micron. 2013 Jul;50:29-34. doi: 10.1016/j.micron.2013.04.002. Epub 2013 Apr 11.
  • Assessing cellular DNA damage from a helium plasma needle. Morales-Ramírez P, Cruz-Vallejo V, Peña-Eguiluz R, López-Callejas R, Rodríguez-Méndez BG, Valencia-Alvarado R, Mercado-Cabrera A, Muñoz-Castro AE. Radiat Res. 2013 Jun;179(6):669-73. doi: 10.1667/RR3223.1. Epub 2013 May 3.

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+