Periodic Table


Atomic number: 67
Atomic weight: 164.93032
Symbol: Ho
Group number: (lanthanide)
Electronic configuration: [Xe].4f11.6s2


Holmium is relatively soft and malleable, and is stable in dry air at room temperature. It oxidises rapidly in moist air and at elevated temperatures. The metal has unusual magnetic properties. The metal is a rare earth metal found in monazite, gadolinite and other minerals.

General information

Discoveror: J. L. Soret and Delafontaine
Date discovered: 1878
Discovered at: Switzerland
Meaning of name: From the Greek word "Holmia" meaning "Sweden"

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m-3: 8795
Molar volume/cm3: 18.74

Radii /pm

Atomic: 226
Covalent (single bond):
Pauling radius for the ion [Ho]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius205.1no datano data27.5


Both values are quoted on the Pauling scale.

Pauling: 1.23
Allred Rochow: 1.10

Crystal Structure

structure: hcp (hexagonal close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.


Temperatures (/K)

melting point: 1734
boiling point: 2993

Enthalpies /kJ mol-1

fusion: 17.0
vaporization: 265

single bond enthalpies:
Ho-F Ho-Cl Ho-Br Ho-I Ho-Ho
no data no data no data 305 84

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
165Ho164.930319 (4)100

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Ho.html