Holmium (Ho)

Stable Isotopes of Holmium

Isotope Z(p) N(n) Atomic Mass Natural Abundance Nuclear Spin
Ho-165  67  98  164.930319 100.00%  7/2- 


Holmium was discovered in 1878 by Marc Delafontaine and Jacques-Louis Soret. Its name comes from the Greek word Holmia, meaning “Sweden.”

A soft, lustrous metal with a silver-like appearance, holmium is a hexagonal crystalline solid with a metallic luster. It has one of the highest nuclear moments of any rare earth. It is paramagnetic, with a magnetic moment of 11.2 Bohr magnetons. It reacts slowly with water and is soluble in dilute acids. The metal forms fluoride, hydroxide, phosphate, oxalate and carbonate that are insoluble in water. Its water-soluble salts are chloride, bromide, iodide, acetate, nitrate and sulfate. Reactions of holmium with acids yield corresponding salts. The finely divided metal burns in oxygen at ordinary temperatures.

Holmium metal does not have significant commercial application. However, because of its unusual magnetic properties, it is being used in research studies to explore the magnetic and alloying behaviors of metals.

Properties of Holmium

Name Holmium 
Symbol Ho 
Atomic number 67 
Atomic weight 164.93 
Standard state Solid at 298 ºK 
CAS Registry ID 7440-60-0 
Group in periodic table N/A 
Group name Lanthanoid 
Period in periodic table 6 (Lanthanoid) 
Block in periodic table f-block 
Color Silvery white 
Classification Metallic 
Melting point 1472 °C
Boiling point 2695 °C
Vaporization point 2694 ºC
Thermal conductivity 16.2 W/(m·K)
Electrical resistivity 87.0 µΩ·cm at 25 ºC 
Electronegativity 1.2 
Specific heat 0.38 kJ/kg K 
Heat of vaporization 265 kJ·mol-1
Heat of fusion 17 kJ·mol-1
Density of liquid 8.34 g/cm3 at 1472 °C 
Density of solid 8.78 g/cm3  
Electron configuration [Xe]4f116s2 
Metallic radius 1.767 Å (coordination number 12)
Atomic volume 18.78 cm3/mol
Oxidation state  +3 

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