Holmium

Holmium, ₆₇Ho

Holmium
Pronunciation	/ˈhoʊlmiəm/ ​(HOHL-mee-əm)
Appearance	silvery white
Standard atomic weight Ar°(Ho)
	164.930329±0.000005[1] 164.93±0.01 (abridged)[2]
Holmium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson – ↑ Ho ↓ Es dysprosium ← holmium → erbium
Atomic number (Z)	67
Group	f-block groups (no number)
Period	period 6
Block	f-block
Electron configuration	[Xe] 4f11 6s2
Electrons per shell	2, 8, 18, 29, 8, 2
Physical properties
Phase at STP	solid
Melting point	1734 K ​(1461 °C, ​2662 °F)
Boiling point	2873 K ​(2600 °C, ​4712 °F)
Density (at 20° C)	8.795 g/cm3 [3]
when liquid (at m.p.)	8.34 g/cm3
Heat of fusion	17.0 kJ/mol
Heat of vaporization	251 kJ/mol
Molar heat capacity	27.15 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1432 1584 (1775) (2040) (2410) (2964)
Atomic properties
Oxidation states	common: +3 0,[4] +1,? +2?
Electronegativity	Pauling scale: 1.23
Ionization energies	1st: 581.0 kJ/mol 2nd: 1140 kJ/mol 3rd: 2204 kJ/mol
Atomic radius	empirical: 176 pm
Covalent radius	192±7 pm
Spectral lines of holmium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 357.80 pm c = 561.77 pm (at 20 °C)[3]
Thermal expansion	poly: 11.2 µm/(m⋅K) (at r.t.)
Thermal conductivity	16.2 W/(m⋅K)
Electrical resistivity	poly: 814 nΩ⋅m (at r.t.)
Magnetic ordering	paramagnetic
Young's modulus	64.8 GPa
Shear modulus	26.3 GPa
Bulk modulus	40.2 GPa
Speed of sound thin rod	2760 m/s (at 20 °C)
Poisson ratio	0.231
Vickers hardness	410–600 MPa
Brinell hardness	500–1250 MPa
CAS Number	7440-60-0
History
Discovery	Per Theodor Cleve, Jacques-Louis Soret and Marc Delafontaine (1878)
Isotopes of holmium v e
Main isotopes[5] Decay abun­dance half-life (t1/2) mode pro­duct 163Ho synth 4570 y ε 163Dy 164Ho synth 28.8 min ε 164Dy β− 164Er 165Ho 100% stable 166Ho synth 26.812 h β− 166Er 166m1Ho synth 1132.6 y β− 166Er 167Ho synth 3.1 h β− 167Er
Category: Holmium view talk edit | references

Holmium is a chemical element; it has symbol Ho and atomic number 67. It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like many other lanthanides, holmium is too reactive to be found in native form, as pure holmium slowly forms a yellowish oxide coating when exposed to air. When isolated, holmium is relatively stable in dry air at room temperature. However, it reacts with water and corrodes readily, and also burns in air when heated.

In nature, holmium occurs together with the other rare-earth metals (like thulium). It is a relatively rare lanthanide, making up 1.4 parts per million of the Earth's crust, an abundance similar to tungsten. Holmium was discovered through isolation by Swedish chemist Per Theodor Cleve. It was also independently discovered by Jacques-Louis Soret and Marc Delafontaine, who together observed it spectroscopically in 1878. Its oxide was first isolated from rare-earth ores by Cleve in 1878. The element's name comes from Holmia, the Latin name for the city of Stockholm.^[6][7][8]

Like many other lanthanides, holmium is found in the minerals monazite and gadolinite and is usually commercially extracted from monazite using ion-exchange techniques. Its compounds in nature and in nearly all of its laboratory chemistry are trivalently oxidized, containing Ho(III) ions. Trivalent holmium ions have fluorescent properties similar to many other rare-earth ions (while yielding their own set of unique emission light lines), and thus are used in the same way as some other rare earths in certain laser and glass-colorant applications.

Holmium has the highest magnetic permeability and magnetic saturation of any element and is thus used for the pole pieces of the strongest static magnets. Because holmium strongly absorbs neutrons, it is also used as a burnable poison in nuclear reactors.