Why does yttrium only exhibit a +3 oxidation state?

Yttrium has the electron configuration [Kr] 4d1 5s2. Losing all three valence electrons (one 4d and two 5s) gives it the stable krypton noble-gas configuration. The energy cost is recovered by lattice and hydration energies in Y3+ compounds. Unlike many transition metals, yttrium has only one d-electron and no other partially filled sub-shell accessible at ordinary energies, so intermediate states like +2 are not stabilized.

Does yttrium ever exhibit a +2 or +1 oxidation state?

No stable +2 or +1 compounds are known under ordinary conditions. A few metastable Y2+ species have been detected in gas-phase or matrix-isolation experiments, but they rapidly convert to Y3+ compounds. There is no inert-pair analogy and no half-filled d-shell to stabilize lower states.

What is yttrium's electron configuration?

Ground state: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d1 5s2, or in noble-gas notation [Kr] 4d1 5s2. When ionized to Y3+, all three valence electrons are removed, leaving the 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 core identical to krypton.

What makes yttrium behave like a lanthanide despite being a transition metal?

Yttrium sits directly above the lanthanides in Group 3 and has an ionic radius (Y3+ = 0.90 Å) that closely matches the larger lanthanide ions (Dy3+ = 0.91 Å, Ho3+ = 0.90 Å). Its exclusively +3 oxidation state and similar chemistry cause it to co-precipitate with rare-earth elements in nature and to be classified as a rare-earth element in practice, even though it is a d-block metal.

What are the most important yttrium compounds?

Yttrium oxide (Y2O3) is the most widely used — it is a phosphor host (red phosphor in displays), a stabilizer for zirconia ceramics (YSZ), and a laser host (YAG). YBa2Cu3O7 (YBCO) was the first material to exhibit superconductivity above liquid nitrogen temperature (92 K). YF3 and YCl3 are common precursors for synthesis. All feature Y in the +3 state.

How does yttrium compare to scandium and lanthanum in Group 3?

All three Group 3 elements show exclusively +3 in stable compounds. Scandium (Sc, Z=21) is smaller with ionic radius 0.75 Å; yttrium (Y, Z=39) is intermediate at 0.90 Å; lanthanum (La, Z=57) is largest at 1.03 Å. Their chemistry is similar but yttrium shows the closest match to the mid-series lanthanides, explaining its occurrence and processing alongside rare earths in mining.

Yttrium Oxidation States

Name: Yttrium Oxidation States
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Author: Nham Vu

Reference for yttrium oxidation states: Y is exclusively +3 in all known stable compounds, with its electron configuration, ionization energies, and common compounds explained.

Atomic # 39 Y Yttrium

Atomic Mass

88.9058 u

Group

3 (IIIB)

Period

Block

d-block

Electronegativity

1.22 (Pauling)

Oxidation States

+3 (only stable)

Yttrium exhibits one known oxidation state in stable compounds: +3. Its ground-state configuration is [Kr] 4d¹ 5s² — losing all three valence electrons attains the stable krypton core. Unlike many d-block neighbors, yttrium has only one 4d electron and no additional valence sub-shells at accessible energies, so no intermediate oxidation state is thermodynamically stable. The result is chemistry that closely parallels the lanthanide elements.

Oxidation State	Stability	Notes
+3	Stable	Universal state in all known compounds. Y loses 4d¹ 5s² to achieve [Kr] configuration. High lattice and hydration energies drive Y³⁺ formation.
0	Elemental only	Assigned to pure yttrium metal by convention. Not a compound oxidation state.
+2	Metastable only	Detected in matrix-isolation or gas-phase experiments. No stable solid-state +2 compound is known. Rapidly converts to Y(0) + Y³⁺.
+1	Not observed	No +1 yttrium compounds are known. The single 4d electron provides no special stabilization for a +1 state.

Ionization Energies
IE₁ = 600.0 kJ/mol | IE₂ = 1180 kJ/mol | IE₃ = 1980 kJ/mol | IE₄ = 5847 kJ/mol
The large jump from IE₃ to IE₄ confirms +3 as the maximum stable state — IE₄ would break into the stable krypton core.

All stable yttrium compounds feature Y in the +3 oxidation state. Y³⁺ is a hard Lewis acid (small, highly charged) and forms predominantly ionic bonds with hard donor ligands such as oxides, fluorides, and hydroxides. Its ionic radius (0.90 Å for 6-coordinate Y³⁺) closely matches several lanthanide ions, giving yttrium very similar coordination and crystal chemistry to the rare earths.

Compound	Formula	Y State	Notes
Yttrium Oxide (Yttria)	Y₂O₃	+3	High-melting refractory oxide (mp 2439 °C); host matrix for red phosphors in displays; stabilizer for zirconia ceramics (YSZ); used in laser host crystals.
Yttrium Barium Copper Oxide	YBa₂Cu₃O₇	+3	YBCO — first material to superconduct above 77 K (liquid nitrogen); Y is in the +3 state; copper mixed-valence drives superconductivity. Critical for HTS research.
Yttrium Aluminum Garnet	Y₃Al₅O₁₂ (YAG)	+3	Synthetic garnet used as laser gain medium (Nd:YAG at 1064 nm, Er:YAG at 2940 nm) and as a synthetic gemstone. Y provides the structural framework.
Yttrium Fluoride	YF₃	+3	Common precursor and starting material; used in optical coatings and fluoride glass; also a precursor for upconversion nanoparticles (NaYF₄).
Yttrium Chloride	YCl₃	+3	Anhydrous and hydrated forms used as laboratory reagents; starting material for organometallic yttrium chemistry and thin-film deposition.
Yttrium Hydroxide	Y(OH)₃	+3	White precipitate formed by adding base to Y3+ solutions; precursor to Y2O3 via calcination; intermediate in rare-earth processing.
Yttrium Nitrate	Y(NO₃)₃	+3	Water-soluble salt; used in solution-based synthesis of yttrium phosphors and coatings; widely available laboratory reagent.
Yttrium Vanadate	YVO₄	+3	Host for europium-doped red phosphors (YVO₄:Eu); also used as a birefringent crystal in optical components and laser polarizers.
Yttrium Iron Garnet	Y₃Fe₅O₁₂ (YIG)	+3	Ferrimagnetic garnet used in microwave devices, magneto-optical components, and spin-wave research. Y3+ occupies dodecahedral sites.
Yttrium Sulfide	Y₂S₃	+3	Used as a yellow-orange pigment ("Sienna pigment") that is more stable than cadmium sulfide analogs; also studied for IR optics.

Ground State Configuration

Core

Core (completes [Ar] + 3d10 = [Kr] core)

Core

Core (completes [Kr])

Valence — lost on 3rd ionization

Valence — lost on 1st and 2nd ionization

Notation

Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹ 5s²

Noble gas: [Kr] 4d¹ 5s²

Y³⁺ ion: [Kr] = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶

Ionization Steps

[Kr] 4d¹ 5s²

Neutral atom — 3 valence electrons

Y⁺

[Kr] 4d¹ 5s¹

Remove one 5s electron (IE₁ 600.0 kJ/mol)

Y²⁺

[Kr] 4d¹

Remove second 5s electron (IE₂ 1180 kJ/mol)

Y³⁺

[Kr]

Remove the 4d electron (IE₃ 1980 kJ/mol) — stable, noble-gas core

Y⁴⁺

[Kr]−1e

Break into [Kr] core (IE₄ 5847 kJ/mol) — not accessible under ordinary conditions

Why the large jump at IE₄? Removing the first three electrons clears the outer 4d/5s shell, reaching the stable [Kr] krypton core. The fourth ionization would pull an electron from the filled 4p shell of that noble-gas core, requiring nearly three times the energy of IE₃ (5847 vs 1980 kJ/mol). This discontinuity directly explains why +3 is the ceiling for yttrium under all ordinary conditions.

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Summary

Reference for yttrium oxidation states: Y is exclusively +3 in all known stable compounds, with its electron configuration, ionization energies, and common compounds explained.

How it works

Click a tab — Oxidation States, Compounds, Electron Config, or Physical Props — to explore each area.
The Oxidation States panel explains why +3 is the only known state, with a table of known states and stability notes.
The Compounds panel lists common yttrium compounds with their formulas, oxidation states, and applications.
The Electron Config panel shows the orbital filling diagram and ionization energy steps to Y3+.
The Physical Props panel provides atomic and material data for quick reference.
Click any monospace table cell to copy its value to your clipboard.

Use cases

Students studying Group 3 and transition metal oxidation state trends.
Chemistry teachers preparing lesson material on d-block elements and lanthanide-like behavior.
Materials scientists working with yttrium-stabilized zirconia (YSZ) or YBCO superconductors.
Researchers needing a quick atomic data reference for yttrium in phosphor or laser materials.
Anyone preparing for chemistry exams covering Period 5 or Group 3 elements.

Frequently Asked Questions

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