Ho - Holmium
|
- Atomic Number: 67
- Atomic Weight (Mass): 164.93030
- Melting Point: 1545 °C
- Boiling Point: 1727 °C
- Orbital Class: 4f
- Orbital: [Xe] 4f11 6s2
- Class: Lanthanides
- Electronegativity: 1.2
- Density: 8.8 g.cm-3
- Van der Waals Radius: unknown
- Ionic Radius: unknown
- First Ionization Energy: 580.99 kJ mol-1
- Second Ionization Energy: 1138.54 kJ mol-1
- Third Ionization Energy: 2203.74 kJ mol-1
- Heat of Fusion: 17.2 kJ mol-1
- Heat of Vaporization: 303 kJ mol-1
- Heat of Atomization: 302.63 kJ mol-1
- Electrical Conductivity: 87 µ Ωcm
- Thermal Conductivity: 16.2 W m-1 K-1
- Related To: B, Al, Sc, Co, Ni, Ga, Y, Ag, In, La, Nd, Pm, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Au, Tl, Ac, Cm, Cf, Es, Fm, Md, No, Lr,
|
| Valences |
| I |
II |
III |
IV |
|
V |
VI |
VII |
VIII |
| 1+ |
2+ |
3+ |
4+ |
5+ |
6+ |
7+ |
8+ |
3- |
2- |
1- |
0 |
|
|
Ho |
|
|
|
|
|
|
|
|
|
|
Holmium has the highest magnetic moment (10.6µB) 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 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 is a Block F, Group 3, Period 6 element. The 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 was first discovered by J.L. Soret in 1878.
French: holmium, German: Holmium, Italian: olmio, Portuguese: Holmio, Spanish: holmio, Swedish: Holmium
This element can be purchased in a variety of forms including as metal, compounds, ultra high purity, nanoparticles, and isotopes at www.americanelements.com
Source: www.americanelements.com
#######
Holmium is a chemical element in the periodic table that has the symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a relatively soft and malleable silvery-white metallic element, which is stable in dry air at room temperature. A rare earth metal, it is found in the minerals monazite and gadolinite.
A trivalent metallic rare earth element, holmium has the highest magnetic moment (10.6µB) of any naturally-occurring element and possesses other unusual magnetic properties. When combined with yttrium, it forms highly magnetic compounds.
Holmium is a relatively soft and malleable element that is fairly corrosion-resistant and stable in dry air at standard temperature and pressure. In moist air and at higher temperatures, however, it quickly oxidizes, forming a yellowish oxide. In pure form, holmium possesses a metallic, bright silvery luster. Holmium oxide has some fairly dramatic color changes depending on the lighting conditions. In daylight, it is a tannish yellow color. Under trichromatic light, it is a fiery orange red, almost indistinguishable from the way erbium oxide looks under this same lighting. This has to do with the sharp emission bands of the phosphors, and the absorption bands of both oxides.
Because of its magnetic properties, holmium has been used to create the strongest artificially-generated magnetic fields when placed within high-strength magnets as a magnetic pole piece (also called a magnetic flux concentrator). Since it can absorb nuclear fission-bred neutrons, the element is also used in nuclear control rods.
Source: Wikipedia.org