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Holmium

Holmium , 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. 

Holmium has the highest magnetic moment (10.6?B) of any naturally occurring element. Because of this it has been used to create the highest known magnetic fields by placing it within high strength magnets as a pole piece or magnetic flux concentrator. This magnetic property also has value in yttrium-iron-garnet (YIG) lasers for microwave equipment. Holmium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity); metals in the form offoil, sputtering target, and rod, and compounds as submicron and nanopowder. Holmium lases at a human eye safe 2.08 microns allowing its use in a variety of medical and dental applications in both yttrium-aluminum-garnet (YAG) and yttrium-lanthanum-fluoride (YLF) solid state lasers. The wavelength allows for use in silica fibers designed for shorter wavelengths while still providing the cutting strength of longer wave length equipment. 
Holmium facts, including appearance, CAS #, and molecular formula and safety data, research and properties are available for many specific states, forms and shapes on the product pages listed to the left. Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Nanoparticles and nanopowders provide ultra high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. 

Oxides are available in forms including powders and dense pellets for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Holmium is available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries. 

Holmium is a Block F, Group 3, Period 6 element. The number of electrons in each of Holmium‘s shells is 2, 8, 18, 29, 8, 2 and its electronic configuration is [Xe] 4f11 6s2. In its elemental form holmium‘s CAS number is 7440-60-0. The holmium atom has a radius of 174.3.pm and it‘s Van der Waals radius is unknown. Holmium is only slightly toxic. Holmium has the highest magnetic moment (10.6?B) of any naturally occurring element. Because of this it has been used to create the highest known magnetic fields by placing it within high strength magnets as a pole piece or magnetic flux concentrator. This magnetic property also has value in yttrium-iron-garnet (YIG) lasers for microwave equipment.

All elemental metals, compounds and solutions may be synthesized in ultra high purity (e.g. 99.999%) for laboratory standards, advanced electronic, thin fillm deposition using sputtering targets and evaporation materials, metallurgy and optical materials and other high technology applications. Information is provided for stable (non-radioactive) isotopes. Organo-Metallic Holmium compounds are soluble in organic or non-aqueous solvents. SeeAnalytical Services for information on available certified chemical and physical analysis techniques including MS-ICP, X-Ray Diffraction, PSD and Surface Area (BET) analysis. 

Holmium was first discovered by J.L. Soret in 1878.

Holmium Abundance. The following table shows the abundance of Holmium and each of its naturally occurring isotopes on Earth along with the atomic mass for each isotope.
Isotope Atomic Mass % Abundance on Earth
Ho-165 164.930 100


The following table shows the abundance of Holmium present in the human body and in the universe scaled to parts per billion (ppb) by weight and by atom:
  Typical Human Body Universe
by Weight no data 0.5 ppb
by Atom no data 0.004 ppb


Holmium Safety Data and Biological Role. The safety data for Holmium 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. Holmium compounds have no biological role. 

Ionization Energy. The ionization energy for Holmium (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 580.99 kJ mol-1
2nd Ionization Energy 1138.54 kJ mol-1
3rd Ionization Energy 2203.74 kJ mol-1


Conductivity. As to Holmium‘s electrical and thermal conductivity, the electrical conductivity measured in terms of electrical resistivity @ 20 ?C is 87 ?Ocm and its electronegativities (or its ability to draw electrons relative to other elements) is 1.23. The thermal conductivity of Holmium is 16.2 W m-1 K-1. 

Thermal Properties of Holmium. The melting point and boiling point for Holmium are stated below. The following chart sets forth the heat of fusion, heat of vaporization and heat of atomization.
Heat of Fusion 17.2 kJ mol-1
Heat of Vaporization 303 kJ mol-1
Heat of Atomization 302.63 kJ mol-1


Formula Atomic Number Molecular Weight Electronegativity (Pauling) Density Melting Point Boiling Point Vanderwaals radius Ionic radius Energy of first ionization
Ho 67 164.9 g.mol -1 1.2 8.8 g.cm-3 at 20 °C 1474 °C 2695 °C unknown unknown 580 kJ.mol-1

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