What is the electron configuration of rhenium?

Rhenium (Re, Z=75) has the ground-state electron configuration [Xe] 4f¹⁴ 5d⁵ 6s² in condensed form, or 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁵ 6s² in full.

Why does rhenium have a half-filled 5d subshell?

With 5 electrons in the 5d subshell, each of the five d orbitals holds exactly one electron. This half-filled arrangement has extra stability due to exchange energy, but unlike chromium or molybdenum, rhenium does not promote a 6s electron to achieve it — its configuration follows the standard Aufbau order.

How many valence electrons does rhenium have?

Rhenium has 7 valence electrons: 5 in the 5d subshell and 2 in the 6s subshell. This matches its Group 7 position and its maximum oxidation state of +7 (e.g., in Re₂O₇).

What block and period is rhenium in?

Rhenium is in Period 6, Group 7, and belongs to the d-block of the periodic table. It is a transition metal positioned between tungsten (Group 6) and osmium (Group 8).

What is the noble-gas core for rhenium?

The noble-gas core is [Xe], representing the filled 54-electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ of xenon. The 4f¹⁴ electrons are added on top of this core before the 5d orbitals begin filling.

What are the common oxidation states of rhenium?

Rhenium exhibits a wide range of oxidation states from −1 to +7, with +7 (in perrhenate, ReO₄⁻) and +4 being the most stable. This broad range reflects the availability of both 5d and 6s electrons for bonding.

Why is rhenium so rare and expensive?

Rhenium has an average crustal abundance of only about 0.7 ppb, making it one of the rarest stable elements. Most rhenium is recovered as a by-product of molybdenum refining. Its scarcity, combined with critical uses in superalloy turbine blades and catalysts, drives its high market price.

Rhenium Electron Configuration

Quick reference for rhenium's electron configuration ([Xe] 4f¹⁴ 5d⁵ 6s²), orbital box diagram, quantum numbers, and key atomic properties.

Z = 75 Re Rhenium

Rhenium — Electron Configuration

Atomic number 75 · Transition metal · Period 6, Group 7 · d-block

[Xe] 4f¹⁴ 5d⁵ 6s² 75 electrons 7 valence e⁻ 5d⁵ half-filled

Subshell Breakdown

Subshell	Type	Electrons	Max Capacity	Notation
1s	s orbital, shell n=1	2	2	1s²
2s	s orbital, shell n=2	2	2	2s²
2p	p orbitals, shell n=2	6	6	2p⁶
3s	s orbital, shell n=3	2	2	3s²
3p	p orbitals, shell n=3	6	6	3p⁶
3d	d orbitals, shell n=3	10	10	3d¹⁰
4s	s orbital, shell n=4	2	2	4s²
4p	p orbitals, shell n=4	6	6	4p⁶
4d	d orbitals, shell n=4	10	10	4d¹⁰
4f	f orbitals, shell n=4	14	14	4f¹⁴
5s	s orbital, shell n=5	2	2	5s²
5p	p orbitals, shell n=5	6	6	5p⁶
5d	d orbitals, shell n=5	5	10	5d⁵
6s	s orbital, shell n=6	2	2	6s²
Total		75

Full Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁵ 6s²

All 75 electrons written across 14 subshells.

Noble-Gas Shorthand

[Xe] 4f¹⁴ 5d⁵ 6s²

[Xe] = the filled 54-electron xenon core.

Shell Fill Summary

Shell 1 (n=1) — 1s² 2 / 2 electrons (100%)

Shell 2 (n=2) — 2s² 2p⁶ 8 / 8 electrons (100%)

Shell 3 (n=3) — 3s² 3p⁶ 3d¹⁰ 18 / 18 electrons (100%)

Shell 4 (n=4) — 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 32 / 32 electrons (100%)

Shell 5 (n=5) — 5s² 5p⁶ 5d⁵ 13 / 32 electrons (41%)

Shell 6 (n=6) — 6s² 2 / 32 electrons (6%)

Shell 5 can hold up to 32 electrons (5s + 5p + 5d + 5f). Rhenium uses only 13. Shell 4 is completely filled at 32 electrons via the 4f subshell.

Orbital Box Diagram — Valence Shells (5d, 6s)

The [Xe] 4f¹⁴ core is shown collapsed. The diagram focuses on the partially filled 5d and the filled 6s subshells.

[Xe] 4f¹⁴

54 + 14 = 68 electrons fully filled — xenon core plus seven paired 4f orbitals

5 electrons, one per orbital (spin up) — half-filled, maximum multiplicity

2 electrons (paired) — filled outermost s subshell

Each box represents one orbital. Opposing arrows represent paired electrons (spins +½ and −½). The five unpaired 5d electrons follow Hund's rule: one per orbital before any pairing begins.

Quantum Numbers — Valence Electrons (5d⁵ 6s²)

Electron #	n	l	mₗ	mₛ	Subshell
71	5	2	-2	+½	5d
72	5	2	-1	+½	5d
73	5	2	0	+½	5d
74	5	2	1	+½	5d
75	5	2	2	+½	5d
55	6	0	0	+½	6s
56	6	0	0	−½	6s

n = principal quantum number; l = azimuthal (l=2 → d, l=0 → s); mₗ = magnetic quantum number; mₛ = spin. The 68 inner electrons comprise [Xe] (electrons 1–54) plus the filled 4f¹⁴ subshell (Aufbau positions 57–70).

Identity

SymbolRe Atomic number75 Atomic mass186.207 u Group7 (VIIB) Period6 Blockd-block CategoryTransition metal

Physical Properties

State (25 °C)Solid Melting point3186 °C Boiling point5596 °C Density21.02 g/cm³ ColorSilvery-gray Crystal structureHCP

Electronic Properties

Valence electrons7 (5d⁵ 6s²) Common oxidation states+7, +4, +6 Max oxidation state+7 Electronegativity1.9 (Pauling) 1st ionization energy760 kJ/mol Magnetic behaviorParamagnetic

Context & Uses

Third-highest melting point of all elements (3186 °C), after tungsten and carbon.
Used in nickel superalloys for jet engine turbine blades, where heat resistance is critical.
Key catalyst in petroleum refining (platforming) to produce unleaded high-octane fuel.
One of the rarest stable elements in Earth's crust (~0.7 ppb), recovered mainly from molybdenite ore.
Discovered in 1925 by Noddack, Tacke, and Berg — the last stable element to be found.

Summary

Rhenium (Re) is element 75, a rare d-block transition metal in Period 6, Group 7. Its ground-state electron configuration is [Xe] 4f¹⁴ 5d⁵ 6s², written in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁵ 6s². This tool shows the subshell breakdown, orbital box diagram with spin arrows, quantum numbers for the outermost electrons, and key physical and chemical data for rhenium.

How it works

The Aufbau principle fills orbitals from lowest to highest energy, following the n+l rule.
Rhenium's 75 electrons fill through xenon's 54-electron core before adding the 4f, 5d, and 6s electrons.
The 4f subshell takes 14 electrons across seven orbitals before the 5d begins filling.
The 5d subshell holds 5 electrons — one per orbital, following Hund's rule for maximum spin multiplicity.
The 6s subshell holds 2 paired electrons as the outermost (valence s) electrons.
Noble-gas shorthand [Xe] replaces the first 54 electrons, leaving [Xe] 4f¹⁴ 5d⁵ 6s².

Use cases

Reference the full or condensed electron configuration for chemistry coursework or exams.
Understand why rhenium is a d-block element with high oxidation states (+7 maximum).
Visualize the 5d orbital half-fill that drives rhenium's paramagnetic behavior.
Compare rhenium to its Period 6 neighbors tungsten (5d⁴) and osmium (5d⁶).
Verify quantum numbers when solving atomic structure problems.
Teaching aid for lanthanide contraction and 4f filling in heavy transition metals.
Explore why rhenium has the third-highest melting point of all elements.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu