Predict the formula of niobium(V) oxide.
Nb5+ with O2- crosses to Nb2O5 — two niobiums (+10) balancing five oxides (-10). This oxide is the raw material for lithium niobate, the crystal inside many phone signal filters.
What Is the Charge of Niobium?
Niobium commonly forms Nb3+ Nb5+ in introductory ionic compounds.
Niobium's dominant state is +5 — Nb2O5 and NbCl5 are the compounds you'd meet first — with +3 as the main lower state. The +5 oxide film is why niobium jewelry can be anodized into brilliant rainbow colors without dyes.
| Element | Niobium |
|---|---|
| Symbol | Nb |
| Atomic number | 41 |
| Common ionic charge | +3, +5 |
| Common ions | Nb3+, Nb5+ |
Visual reference
Niobium element image and atomic model
Images are used as visual references; charge rules still depend on the compound.
Where Niobium's charge options come from
Niobium is [Kr]4d4 5s1. Committing all five outer electrons reaches the krypton core, making +5 the resting state, much as vanadium above it favors +5. The intermediate states are real but belong to inorganic-chemistry electives, not intro courses.
This is a classroom reference range, not an exhaustive list of all oxidation states.
The trap in Niobium problems
Assuming the anodized colors on niobium rings come from colored ions. The metal stays neutral; a transparent Nb2O5 layer of controlled thickness creates the colors by light interference — the same physics as oil films on water.
Worked example: Nb in a formula problem
Nb3+ and Nb5+ in real compounds
NbCl3
Niobium chloride
Nb3+ balances chloride ions.
Nb2O3
Niobium oxide
Niobium can form oxides where total positive and negative charge balances.
Questions students ask about niobium
Why is niobium in superconducting magnets?
Niobium-titanium and niobium-tin alloys (neutral metals, charge 0) superconduct below about 10 K. MRI machines and particle accelerators wind kilometers of it — no ionic chemistry involved.
How is niobium related to tantalum?
They sit in the same group, both defaulting to +5, with nearly identical ionic radii — a lanthanide-contraction coincidence that made them notoriously hard to separate; their shared ore even yielded intertwined names (niobium was once 'columbium').
Is niobium hypoallergenic because of its charge?
Because of its lack of released charge, yes: the sealed Nb2O5 surface dissolves essentially no ions into skin, unlike nickel, whose released Ni2+ triggers allergies.
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.