Dysprosium

Koushik 26/06/2026 19:58:08 Updated 26/06/2026 19:58:08

Property	Value
Atomic Number	66
Element	Dysprosium
Symbol	Dy
Atomic Mass	162.500 u
Number of Neutrons	98 (most common isotope, Dysprosium-164)
Number of Protons	66
Number of Electrons	66
Period	6
Group	Lanthanide (no fixed group number)
Phase	Solid
Radioactive	No (some isotopes are radioactive)
Natural	Yes
Metal	Yes
Nonmetal	No
Metalloid	No
Type	Lanthanide
Atomic Radius	228 pm
Electronegativity	1.22 (Pauling scale)
First Ionization Energy	5.939 eV
Density	8.55 g/cm³
Melting Point	1412 °C
Boiling Point	2567 °C
Number of Isotopes	7 naturally occurring (Dy-156, Dy-158, Dy-160, Dy-161, Dy-162, Dy-163, Dy-164)
Discoverer	Paul-Émile Lecoq de Boisbaudran
Year	1886
Specific Heat	0.170 J/g·K
Number of Shells	6
Number of Valence Electrons	3