Write the formula for bismuth(III) oxide, and one place you'd meet it.
Bi3+ with O2- crosses to Bi2O3 — the yellow oxide in lead-free solders' oxide layers, fireworks 'dragon's eggs' crackle stars, and yellow ceramic glazes.
What Is the Charge of Bismuth?
Bismuth commonly forms Bi3+ Bi5+ in introductory ionic compounds.
Bismuth is +3 in nearly everything — Bi2O3, BiOCl (the pearlescent shimmer in cosmetics), and bismuth subsalicylate, the pink active ingredient of stomach remedies. The +5 state exists (NaBiO3) purely as a powerful lab oxidizer.
| Element | Bismuth |
|---|---|
| Symbol | Bi |
| Atomic number | 83 |
| Common ionic charge | +3, +5 |
| Common ions | Bi3+, Bi5+ |
Visual reference
Bismuth element image and atomic model
Images are used as visual references; charge rules still depend on the compound.
How Bismuth's outer electrons decide its charge
Bismuth is [Xe]4f14 5d10 6s2 6p3. The three 6p electrons leave for +3; the 6s pair, locked by the inert-pair effect at its strongest, joins only under duress — which is why bismuthate (+5) tears electrons from almost anything to get back down to +3.
The Bismuth mistake worth a warning
Lumping bismuth with its toxic neighbors lead, thallium, and polonium. Bi3+ compounds are so poorly absorbed and readily excreted that people literally swallow them for indigestion — the periodic table's sharpest toxicity cliff sits between Pb and Bi.
Worked example: Bi in a formula problem
Bi3+ and Bi5+ in real compounds
BiCl3
Bismuth chloride
Bi3+ balances chloride ions.
Bi2O3
Bismuth oxide
Bismuth can form oxides where total positive and negative charge balances.
Questions students ask about bismuth
Is bismuth really (barely) radioactive?
Bi-209's half-life is 2×10^19 years — a billion times the universe's age. Discovered decaying only in 2003, it is radioactive on paper and stable for every human purpose; its +3 chemistry never notices.
What makes bismuth crystals those rainbow staircases?
Hopper crystals of the neutral metal grow stepped edges, and a thin bismuth-oxide film (+3) interferes with light to paint the colors — geometry from the metal, rainbow from the charge-3 skin.
Why is NaBiO3 kept on analytical shelves?
Sodium bismuthate's Bi5+ is one of few reagents strong enough to drive manganese all the way up to purple permanganate in a test tube — the standard spot test for manganese in steel.
How do I use this charge in formulas?
Combine positive and negative ions so the total charge is zero — or let the ionic compound calculator do the crossing for you. The full chart lives on the periodic table with charges.
Where this data comes from
Charges and element facts on this page are checked against the primary references below. Found an error? Email hello@periodictablewithcharges.com — corrections ship in the next content update. See how this site is edited.