Helium information, including Technical Data, Safety Data and its 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.
Helium is a Block S, Group 18, Period 1 element. The electronic configuration is 1s2. In its elemental form helium's CAS number is 7440-59-7. The helium atom has a radius of 140.pm and it's Van der Waals radius is 120.pm. Helium was discovered by Pierre Jules César Janssen and Sir William Ramsay in 1868.
Helium Abundance. The following table shows the abundance of helium and each of its naturally occurring isotopes on Earth along with the atomic mass for each isotope. |
Hélium 
Helium
Elio 
Hélio 
Helio 
HeliumIsotope |
Atomic Mass |
% Abundance on Earth |
He-3 |
3.016029310 |
0.01 |
He-4 |
4.002603250 |
99.99 |
Helium Safety Data. The safety data for helium metal, nanoparticles and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the left margin.
Ionization Energy. The ionization energy for helium (the least required energy to release a single electron from the atom in it's ground state in the gas phase) is stated in the following table: |
1st Ionization Energy |
708.58 kJ mol-1 |
2nd Ionization Energy |
1411.81 kJ mol-1 |
3rd Ionization Energy |
2943.07 kJ mol-1 |
Conductivity. As to helium's electrical and thermal conductivity, the electrical conductivity measured in terms of electrical resistivity @ 20 ºC is - µOcm and its electronegativities (or its ability to draw electrons relative to other elements) is -. The thermal conductivity of helium is 0.155 W m-1 K-1.
Thermal Properties of Helium. The melting point and boiling point for helium are stated below. The following chart sets forth the heat of fusion, heat of vaporization and heat of atomization. |
Heat of Fusion |
0.021 kJ mol-1 |
Heat of Vaporization |
0.082 kJ mol-1 |
Heat of Atomization |
0 kJ mol-1 |
| Formula | Atomic Number | Molecular Weight | Electronegativity (Pauling) | Density | Melting Point | Boiling Point |
Vanderwaals radius |
Ionic radius | Energy of first ionization |
| He | 2 | 4.002602 g.mol -1 | - | 0.08988 g.cm-3 | -272.2 °C | -268.93 °C | .120 nm | 128pm | 708.58 kJ.mol-1 |
| PRODUCT CATALOG | UK Operations | Submicron & Nanopowder | Tolling | Ultra High Purity | Sputtering Target | Crystal Growth | Rod, Plate, Powder, etc. | Foil |
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