Transition metalElement 25 · d-block

Manganese (Mn)

Manganese (Mn) is a transition metal with atomic number 25 and a standard atomic weight of 54.938. At room temperature it is a solid that melts at 1,246 °C and boils at 2,061 °C.

25MnManganese54.938

Atomic number

protons

Atomic weight

54.938

CIAAW 2024

Melting point

1,246 °C

1,519.15 K

Boiling point

2,061 °C

2,334.15 K

Density

7.3 g/cm³

near room temperature

Electronegativity

1.55

Pauling scale

State at 25 °C

Solid

Discovered

1774

Sweden

Manganese at a glance

Identity

Symbol	Mn
Atomic number (Z)	25
Atomic weight	54.938 ± 0.001 (CIAAW 2024)
Category	Transition metal
Group	7
Period	4
Block	d-block
CAS number	7439-96-5

Atomic properties

Electron configuration	[Ar] 3d⁵ 4s² Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s²
Electrons per shell	2, 8, 13, 2
Oxidation states	+2, +4, +7 Less common: -3, -1, 0, +1, +3, +5, +6
Electronegativity (Pauling)	1.55
First ionisation energy	7.434 eV (717.3 kJ/mol) 2nd: 15.64 eV · 3rd: 33.668 eV
Atomic radius (empirical)	140 pm
Covalent radius	119 pm
Van der Waals radius	205 pm

Physical properties

State at 25 °C	Solid
Melting point	1,246 °C · 2,274.8 °F · 1,519.15 K
Boiling point	2,061 °C · 3,741.8 °F · 2,334.15 K
Density	7.3 g/cm³
Specific heat capacity	0.479 J/(g·K)
Crystal structure	Cubic

Isotopes & abundance

Natural occurrence	Primordial
Radioactive	No
Natural isotopes (abundance)	⁵⁵Mn 100%
Stable isotopes	4
Known isotopes	31
Abundance in Earth's crust	950 mg/kg
Abundance in seawater	0.0002 mg/L

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

Manganese electron configuration

Manganese has 25 electrons. Written in short form, its ground-state configuration is [Ar] 3d⁵ 4s² — the electrons of the noble gas argon, plus 3d⁵ 4s².Written out in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s².

3d↑↑↑↑↑

4s↑↓

Discovery and name

Discovered

1774 — Johan Gottlieb Gahn (identified by Carl Wilhelm Scheele) · Sweden.

Name

Latin magnes, magnet (via 'magnesia nigra').

Known for

Essential to steelmaking — about 90% of manganese goes into steel. Also used in aluminium cans and the cathodes of alkaline and lithium-ion batteries.

Isotopes of manganese

Naturally occurring manganese is a mix of 1 isotope. Each has 25 protons; they differ in the number of neutrons:

Isotope	Protons	Neutrons	Natural abundance	Stability
⁵⁵Mn	25	30	100%	stable

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

Manganese compared with group 7

The other elements in group 7, from top to bottom of the table:

Element	Z	Atomic weight	Melting point	Boiling point	Density	Electronegativity
Manganese	25	54.938	1,246 °C	2,061 °C	7.3 g/cm³	1.55
Technetium	43	[97]	2,157 °C	4,262 °C	11 g/cm³	1.9
Rhenium	75	186.21	3,185 °C	5,590 °C	20.8 g/cm³	1.9
Bohrium	107	[270]	—	—	37.1 g/cm³ (pred.)	—

Frequently asked questions

6 answers

What is the atomic mass of manganese?

The standard atomic weight of manganese is 54.938 ± 0.001 (CIAAW 2024), so one mole weighs about 54.938 grams.

How many protons, neutrons and electrons does manganese have?

A neutral manganese atom has 25 protons and 25 electrons. Its most common isotope, manganese-55, has 30 neutrons.

What is the electron configuration of manganese?

[Ar] 3d⁵ 4s² (in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s²).

What are the melting and boiling points of manganese?

Manganese melts at 1,246 °C (2,274.8 °F) and boils at 2,061 °C (3,741.8 °F).

Is manganese a metal?

Manganese is a metal. It is in group 7, period 4, and is a solid at room temperature.

Who discovered manganese?

1774 — Johan Gottlieb Gahn (identified by Carl Wilhelm Scheele) (Sweden).