Periodic Table


Atomic number: 66
Atomic weight: 162.50
Symbol: Dy
Group number: (lanthanide)
Electronic configuration: [Xe].4f10.6s2


The element has a metallic, bright silver lustre. It is relatively stable in air at room temperature, but dissolves readily, with the evolution of hydrogen, in mineral acids. The metal is soft enough to be cut with a knife and can be machined without sparking if overheating is avoided. It is a rare earth metal found in minerals such as xenotime, monazite and bastanite.

General information

Discoveror: Paul Emile Lecoq de Boisbaudran
Date discovered: 1886
Discovered at: France
Meaning of name: From the Greek word "dysprositos" meaning "hard to obtain"

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m-3: 8551
Molar volume/cm3: 19.01

Radii /pm

Atomic: 228
Covalent (single bond):
Pauling radius for the ion [Dy]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius207.2no datano data28.3


Both values are quoted on the Pauling scale.

Pauling: 1.22
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: 1680
boiling point: 2840

Enthalpies /kJ mol-1

fusion: 11.1
vaporization: 280

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

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
156Dy155.924277 (8)0.06 (1)
158Dy157.924403 (5)0.10 (1)
160Dy159.925193 (4)2.34 (6)
161Dy160.926930 (4)18.9 (1)
162Dy161.926795 (4)25.5 (2)
163Dy162.928728 (4)24.9 (2)
164Dy163.929171 (4)28.2 (2)

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/Dy.html