Transition metalElement 39 · d-block

Yttrium (Y)

Yttrium (Y) is a transition metal with atomic number 39 and a standard atomic weight of 88.906. At room temperature it is a solid that melts at 1,522 °C and boils at 3,345 °C.

39YYttrium88.906

Atomic number

protons

Atomic weight

88.906

CIAAW 2024

Melting point

1,522 °C

1,795.15 K

Boiling point

3,345 °C

3,618.15 K

Density

4.47 g/cm³

near room temperature

Electronegativity

1.22

Pauling scale

State at 25 °C

Solid

Discovered

1794

Finland

Yttrium at a glance

Identity

Symbol	Y
Atomic number (Z)	39
Atomic weight	88.906 ± 0.001 (CIAAW 2024)
Category	Transition metal
Group	3
Period	5
Block	d-block
CAS number	7440-65-5

Atomic properties

Electron configuration	[Kr] 4d¹ 5s² Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹ 5s²
Electrons per shell	2, 8, 18, 9, 2
Oxidation states	+3 Less common: 0, +1, +2
Electronegativity (Pauling)	1.22
First ionisation energy	6.217 eV (599.9 kJ/mol) 2nd: 12.224 eV · 3rd: 20.524 eV
Electron affinity	0.307 eV
Atomic radius (empirical)	180 pm
Covalent radius	163 pm
Van der Waals radius	232 pm

Physical properties

State at 25 °C	Solid
Melting point	1,522 °C · 2,771.6 °F · 1,795.15 K
Boiling point	3,345 °C · 6,053 °F · 3,618.15 K
Density	4.47 g/cm³
Specific heat capacity	0.298 J/(g·K)
Crystal structure	Hexagonal

Isotopes & abundance

Natural occurrence	Primordial
Radioactive	No
Natural isotopes (abundance)	⁸⁹Y 100%
Stable isotopes	1
Known isotopes	35
Abundance in Earth's crust	33 mg/kg
Abundance in seawater	0.000013 mg/L

Atomic weights: CIAAW Abridged Standard Atomic Weights 2024. Other properties: standard reference compilations, checked October 2026; predicted values are marked.

Yttrium electron configuration

Yttrium has 39 electrons. Written in short form, its ground-state configuration is [Kr] 4d¹ 5s² — the electrons of the noble gas krypton, plus 4d¹ 5s².Written out in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹ 5s².

4d↑

5s↑↓

Discovery and name

Discovered

1794 — Johan Gadolin · Finland.

Name

Ytterby, a village in Sweden.

Known for

Used in red phosphors, YAG lasers and yttria-stabilised zirconia. YBCO was the first superconductor above the boiling point of liquid nitrogen.

Isotopes of yttrium

Naturally occurring yttrium is a mix of 1 isotope. Each has 39 protons; they differ in the number of neutrons:

Isotope	Protons	Neutrons	Natural abundance	Stability
⁸⁹Y	39	50	100%	stable

35 isotopes of yttrium are known in our data set (half-lives as published in nuclear data tables).

Yttrium compared with group 3

The other elements in group 3, from top to bottom of the table:

Element	Z	Atomic weight	Melting point	Boiling point	Density	Electronegativity
Scandium	21	44.956	1,541 °C	2,836 °C	2.99 g/cm³	1.36
Yttrium	39	88.906	1,522 °C	3,345 °C	4.47 g/cm³	1.22

Frequently asked questions

6 answers

What is the atomic mass of yttrium?

The standard atomic weight of yttrium is 88.906 ± 0.001 (CIAAW 2024), so one mole weighs about 88.906 grams.

How many protons, neutrons and electrons does yttrium have?

A neutral yttrium atom has 39 protons and 39 electrons. Its most common isotope, yttrium-89, has 50 neutrons.

What is the electron configuration of yttrium?

[Kr] 4d¹ 5s² (in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹ 5s²).

What are the melting and boiling points of yttrium?

Yttrium melts at 1,522 °C (2,771.6 °F) and boils at 3,345 °C (6,053 °F).

Is yttrium a metal?

Yttrium is a metal. It is in group 3, period 5, and is a solid at room temperature.

Who discovered yttrium?

1794 — Johan Gadolin (Finland).