PTL:Holmium
From ChemEd Collaborative
| Symbol: | Ho |
|---|---|
| Atomic Number: | 67 |
| Atomic Weight: | 164.93032(2) |
| Electron Configuration: | [Xe] 4f11 6s2 |
| Atomic Radius: | 176.6pm |
| Melting Point: | 1474°C |
| Boiling Point: | 2700°C |
| Heat of Fusion: | 612.2kJ/mol |
| Heat of Vaporization: | 241.0kJ/mol |
Holmium is a member of the lanthanide series of elements, which stretches from lanthanum (La) through lutetium (Lu).
Contents |
Discovered
Following the lead of Mosander and others, who showed that rare earth oxides were often a mixture of several oxides containing lanthanide elements, Cleve studied the oxide erbia in 1879. He found that this oxide contained not only erbium oxide, but also the oxides of holmium and thulium.
In the year previous to Cleve's discovery, J.L. Soret and M. Delafontaine had examined erbia spectroscopically and reported evidence for a new element X. The following year Cleve showed that the mystery element was holmium.
Characteristics
Holmium metal has a silvery appearance. It is soft, ductile, and malleable. In the solid state, the metal has a hexagonal closest packed structure.
Prepared
Like many of the other lanthanide elements, holmium is obtained from the mineral monazite [(Ce,Y,La,Nd,Th)PO4], a mixture of the phosphates of Ca, Th, Ce, and the lanthanides.
The metal can be obtained by reduction of a holmium halide with another metal such as Ca in a nonoxidizing atmosphere.
3 Ca(s) + 2 HoF3(s) 
2 Ho(s) + 3 CaF2(s)
Reactions
Holmium is fairly stable in air, but it will form Ho2O3, holmium(III) oxide. The metal also reacts with mineral acids to give Ho(III) salts and H2 gas.
2 Ho(s) + 6 HCl(aq) 2 HoCl3(aq) + 3 H2(g)
Emission Spectra
This is the emission spectra for Holmium.
