Holmium was discovered by Marc Delafontaine and Jacques-Louis Soret in 1878 in Switzerland. Later in 1878, a Swedish chemist, Per Teodor Cleve independently discovered the element while he was working on erbia earth (erbium oxide).
Atomic number: 67
Atomic weight: 164.93
Group, period, block: n/a, 6, f
Color: silvery white
Electron configuration: 4f11 6s2
Density: 8.79 g/cm-3
Melting point: 1734 K,1461 °C,2662 °F
Boiling point: 2993 K,2720 °C,4928 °F
Oxidation states: 3, 2, 1
Electronegativity: 1.23 (Pauling scale)
Ionization energies: 1st: 581.0 kJ·mol-1
Covalent radius: 192±7 pm
Van der Waals radius: no data
There is one naturally occurring isotope of holmium exists, 165Ho.