Holmium

Kemiallinen merkki: Ho
Järjestysluku: 67
Kategoria: lantanoidit
Ryhmä: n/a
Jakso: 6
Lohko: f
Moolimassa: 164,93032 g/mol
Elektronia kuorilla: 2, 8, 18, 29, 8, 2
CAS-numero: 7440-60-0
Olomuoto: kiinteä
Tiheys: 8,79 kg/l (lähellä huoneenlämpöä)
Sulamispiste: 1734 K (1461 °C, 2662 °F)
Kiehumispiste: 2993 K (2720 °C, 4928 °F)
Kiderakenne: hexagonal
Hapetusluvut: 3
Elektronegatiivisuus: 1,23 (Pauling-asteikko)
Nimen alkuperä: Holmia
Nimen tarkoitus: the Latin name of Stockholm - the discoverer's home town
Faktoja:
- is a relatively soft and malleable silvery-white metallic element
- is stable in dry air at room temperature
- is found in the minerals monazite and gadolinite, not as a free element
- quickly oxidizes in moist air, forming a yellowish oxide
- is commercially extracted via ion-exchange from monazite sand (0,05% holmium) but is still difficult to separate from other rare earths
- its estimated abundance in the Earth's crust is 1,3 mg/kg
- plays no biological role in humans but may b
- as with other rare earths, appears to have a low degree of acute toxicity
- because of its magnetic properties, holmium has been used to create the strongest artificially- generated magnetic fields when placed within high-strength magnets a
- ince it can absorb nuclear fission-bred neutrons, the element is also used in nuclear control rods
- is also used as a yellow or red glass coloring