Why is +3 the most stable oxidation state for bismuth?

Bismuth has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³. In the +3 state it uses only the three 6p electrons for bonding, leaving the 6s² pair inert. Relativistic contraction of the 6s orbital — stronger in bismuth than in any lighter Group 15 member — makes this 6s² pair very stable and energetically costly to remove. This is the extreme end of the inert pair effect seen descending the group.

What compounds contain bismuth in the +5 state?

Bismuth pentafluoride (BiF₅), sodium bismuthate (NaBiO₃), and bismuth(V) oxide (Bi₂O₅) are the main Bi(V) compounds. All are strong to very strong oxidizing agents. NaBiO₃ is a classic qualitative analysis reagent used to oxidize Mn²⁺ to permanganate (MnO₄⁻) to confirm manganese. Bi(V) chemistry is rare because of the enormous energy needed to remove the 6s² electrons.

What is the −3 oxidation state of bismuth?

Bismuth achieves −3 in metal bismuthides — ionic compounds where bismuth accepts three electrons from highly electropositive metals, forming the Bi³⁻ ion. Sodium bismuthide (Na₃Bi) is the classic example. Bismuthine (BiH₃) formally has Bi in the −3 state but is extremely thermally unstable, decomposing at temperatures well below room temperature, unlike ammonia (NH₃) or phosphine (PH₃).

How does bismuth compare to nitrogen and phosphorus in oxidation state stability?

In nitrogen (Period 2), both +5 (as in NO₃⁻ or N₂O₅) and −3 (as in NH₃) are highly accessible. In phosphorus (Period 3), +5 is common (PCl₅, H₃PO₄). Moving down Group 15 through arsenic and antimony to bismuth, relativistic effects increasingly stabilize the ns² pair. Bismuth represents the extreme: the +3 state is so dominant that stable Bi(V) chemistry is essentially limited to a handful of exotic compounds, all strong oxidizers.

Is bismuth safe to handle?

Bismuth is the least toxic of all heavy metals. It has very low bioavailability and does not bioaccumulate, which is why bismuth subsalicylate is the active ingredient in common antacid medications. However, some bismuth compounds (particularly the nitrate and fine powders) require standard laboratory precautions. Bismuth is also used in low-melting alloys (e.g., Wood's metal) and as a lead replacement in shot and plumbing.

What is the most commercially important bismuth compound?

Bismuth trioxide (Bi₂O₃) is the most widely used bismuth compound. It is used in glass and ceramic glazes to add brilliance, in varistor components in electronics, as a yellow-orange pigment, and in nuclear waste immobilization. Bismuth subcarbonate and bismuth subsalicylate are important in pharmaceutical applications (gastrointestinal treatments).

Bismuth Oxidation States

Name: Bismuth Oxidation States
Availability: InStock
Author: Nham Vu

Reference for bismuth (Bi, Z=83) oxidation states (+3 dominant, +5 rare, 0, −3), stability, electron configuration, and example compounds.

Atomic # 83 Bi Bismuth

Atomic Mass

208.980 u

Group

15 (VA)

Period

Block

p-block

Electronegativity

2.02 (Pauling)

Oxidation States

+3 (dominant), +5 (rare), 0, −3

Bismuth exhibits four oxidation states: +5, +3, 0, and −3, with +3 overwhelmingly dominant. Its ground-state configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³. The three 6p electrons are used for bonding in the +3 state, leaving the 6s² pair inert — the inert pair effect at its most extreme in Group 15. The +5 state is exceptionally rare and all Bi(V) compounds are potent oxidizing agents. The −3 state appears only in metal bismuthides.

Oxidation State	Stability	Notes
+5	Rare — extreme oxidant needed	Found in BiF₅, Bi₂O₅, and NaBiO₃. All are strong oxidizing agents. NaBiO₃ oxidizes Mn²⁺ to MnO₄⁻ and is a classic qualitative analysis reagent. Requires removal of both 6s² electrons — far more energetically costly than in nitrogen or phosphorus.
+3	Stable — overwhelmingly dominant	By far the most common state. Includes Bi₂O₃, BiCl₃, Bi₂S₃, and bismuth subsalicylate. The 6s² lone pair remains non-bonding (stereochemically active, causing pyramidal geometry in Bi(III) compounds). Used in pharmaceuticals, glass, ceramics, and cosmetics.
0	Elemental only	Brittle, silvery-pink metal with a distinctive reddish-brown iridescent oxide tarnish. Rhombohedral crystal structure. Used in low-melting alloys (Wood's metal, Rose's metal), as a replacement for lead in shot and fishing weights, and in thermoelectric devices.
−3	Bismuthide / hydride only	Present in metal bismuthides such as Na₃Bi. Bismuthine (BiH₃) formally has Bi in −3 but is extremely unstable, decomposing well below 0 °C. The Bi³⁻ ion is strongly reducing and appears only in intermetallic compounds with very electropositive metals.

Inert Pair Effect — Extreme End of Group 15
Moving down Group 15 from N → P → As → Sb → Bi, relativistic effects grow with atomic number. In bismuth (Z=83), the 6s orbital contracts relativistically so strongly that the 6s² pair is almost chemically inert. Removing these electrons requires extraordinary oxidizing power — only fluorine or very strong oxidants can access Bi(V). This makes bismuth unique among Group 15: it has essentially just one accessible oxidation state (+3) under normal chemical conditions.

Nearly all commercially relevant bismuth chemistry is in the +3 oxidation state. Bismuth trioxide (Bi₂O₃) is the most important industrial compound. Bismuth subsalicylate is the pharmaceutical active ingredient in antacid medications. Rare Bi(V) compounds are all strong oxidizing agents; the −3 state is confined to intermetallic compounds with alkali or alkaline earth metals.

Compound	Formula	Bi State	Notes
Bismuth Trioxide	Bi₂O₃	+3	Yellow solid; the most important commercial bismuth compound. Used in glass, ceramic glazes, varistors, and as a yellow-orange pigment. Amphoteric oxide — dissolves in both acid and concentrated alkali.
Bismuth Trichloride	BiCl₃	+3	White hygroscopic solid; Lewis acid. Hydrolyzes in water to form bismuth oxychloride (BiOCl), a pearl-white pigment used in cosmetics and pearlescent coatings.
Bismuth Oxychloride	BiOCl	+3	Pearl-white lustrous powder; widely used in cosmetics (eye shadow, nail polish, lipstick) for its pearlescent shimmer. Layered structure with strong light-reflecting properties.
Bismuth Sulfide	Bi₂S₃	+3	Black-brown solid; the mineral bismuthinite, a natural ore of bismuth. Semiconductor with a direct band gap of ~1.3 eV; studied for photovoltaic and photocatalytic applications.
Bismuth Subsalicylate	C₇H₅BiO₄	+3	Pink solid; the active ingredient in Pepto-Bismol and similar antacid medications. Treats nausea, diarrhea, and indigestion. Also used against Helicobacter pylori (with antibiotics).
Bismuth Subnitrate	BiONO₃	+3	White powder; used as a pharmaceutical (antacid), in cosmetics, and in the synthesis of other bismuth compounds. Produced by dissolving bismuth in dilute nitric acid.
Bismuth Vanadate	BiVO₄	+3	Bright yellow solid; an important yellow pigment replacing cadmium yellow in paints and coatings. Good opacity, lightfastness, and heat stability. Also a photocatalyst active under visible light.
Sodium Bismuthate	NaBiO₃	+5	Yellow-brown solid; strong oxidizing agent. Classic qualitative analysis reagent — oxidizes Mn²⁺ to permanganate (MnO₄⁻) in acidic solution. One of the few stable Bi(V) compounds.
Bismuth Pentafluoride	BiF₅	+5	White solid; one of the most reactive fluorinating agents known. Fluorinates both inorganic and organic substrates. Fumes in moist air. Bi(V) state accessible here because fluorine's high electronegativity stabilizes the high oxidation state.
Sodium Bismuthide	Na₃Bi	−3	Intermetallic compound; formal Bi³⁻ anion. Strong reducing agent. Reacts vigorously with water. Representative alkali metal bismuthide synthesized at high temperature.

Ground State Configuration

Inert pair — almost never bonds; remains non-bonding in Bi(III)

Three bonding electrons — used in +3 and +5 states

Notation

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p³

Noble gas: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³

Bi³⁺: [Xe] 4f¹⁴ 5d¹⁰ 6s² (inert pair remains)

Bi⁵⁺: [Xe] 4f¹⁴ 5d¹⁰

Ionization Steps

[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³

Neutral atom — three 6p and two 6s valence electrons

Bi³⁺

[Xe] 4f¹⁴ 5d¹⁰ 6s²

Lose three 6p electrons → overwhelmingly dominant ion; 6s² pair is inert

Bi⁵⁺

[Xe] 4f¹⁴ 5d¹⁰

Lose two further 6s electrons → requires extreme oxidants; very rare chemistry

Bi³⁻

[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶

Gain three electrons → bismuthide ion in Na₃Bi; strongly reducing

Why the 6s² pair is almost completely inert in Bi(III)
In Bi³⁺, the 6s² pair is retained as a stereochemically active lone pair that causes pyramidal geometry in Bi(III) compounds — analogous to ammonia but far more pronounced. Relativistic contraction of the 6s orbital in bismuth (Z=83) is strong enough that removing the 6s² electrons to reach Bi⁵⁺ costs far more energy than in antimony or arsenic. Only fluorine and a handful of exotic oxidants can achieve Bi(V), making Bi(III) essentially the sole accessible oxidation state in ordinary chemistry.

Copied!

Summary

Reference for bismuth (Bi, Z=83) oxidation states (+3 dominant, +5 rare, 0, −3), stability, electron configuration, and example compounds.

How it works

Click a tab — Oxidation States, Compounds, Electron Config, or Physical Props — to explore each section.
The Oxidation States panel explains why +3 dominates via the inert pair effect, with a stability table for all four states.
The Compounds panel lists common bismuth compounds with formulas and oxidation state assignments.
The Electron Config panel shows the orbital filling diagram and ionization steps.
The Physical Props panel lists atomic and material data for quick reference.
Click any monospace table cell to copy its value to the clipboard.

Use cases

Students learning p-block trends and the inert pair effect at the bottom of Group 15.
Chemistry teachers preparing lessons on heavy p-block metals or relativistic effects.
Lab chemists working with bismuth compounds in pharmaceuticals, pigments, or catalysis.
Researchers needing quick atomic or redox data for bismuth.
Anyone revising for chemistry exams covering Period 6 or Group 15 elements.

Frequently Asked Questions

Last updated: 2026-07-08 · Reviewed by Nham Vu