Zirconium (Zr)
Transition metal
Zirconium is a corrosion-proof metal with a nuclear superpower: it barely absorbs neutrons, so it clads the fuel rods in most nuclear reactors. Its oxide makes both tough ceramics and the sparkling gem substitute cubic zirconia.
Position on the periodic table
Atomic properties
| Atomic number | 40 |
|---|---|
| Atomic mass | 91.2242 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d2 |
| Noble gas shorthand | [Kr] 4d2 5s2 |
| Electrons per shell | 2, 8, 18, 10, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | +4 |
| Electronegativity (Pauling) | 1.33 |
| Covalent radius (approx.) | 175 pm |
| First ionization energy | 640.1 kJ/mol |
| Electron affinity | 41.8 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 6.52 g/cm³ |
| Melting point | 1854.8 °C (2128 K) |
| Boiling point | 4376.9 °C (4650 K) |
| Appearance | silvery white |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of zirconium
Zirconium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d2, usually shortened to [Kr] 4d2 5s2. Its electrons occupy 5 shells (2, 8, 18, 10, 2), placing it in period 5 of the d-block. Explore it interactively in the electron configuration calculator.
Uses of zirconium
- Nuclear fuel-rod cladding
- Chemical plant equipment
- Ceramic knives and dental crowns (zirconia)
- Cubic zirconia gemstones
Biological role: None known.
Occurrence: Mined as zircon sand, often alongside titanium minerals.
Common compounds of zirconium
ZrO2
Zirconium dioxide (zirconia)
ZrSiO4
Zircon
History and discovery
Discovered: 1789 — Martin Heinrich Klaproth. Name origin: From zircon, its gem mineral (Persian zargun, “gold-coloured”).
Martin Klaproth identified zirconium in 1789 in the gemstone zircon.
Safety notes
Very safe as solid metal or ceramic; zirconium powder is highly flammable.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Zirconium
1. What is the chemical symbol of Zirconium?
2. What is the atomic number of Zirconium?
3. Which category does Zirconium belong to?
4. What is the state of Zirconium at room temperature?
5. Which period of the periodic table is Zirconium in?
Zirconium FAQs
What is the atomic number of zirconium?
Zirconium's atomic number is 40 — every zirconium atom has 40 protons in its nucleus.
What is the symbol for zirconium?
Zr. From zircon, its gem mineral (Persian zargun, “gold-coloured”).
Is zirconium a metal, nonmetal, or metalloid?
Zirconium is classified as a transition metal.
What state is zirconium at room temperature?
At about 25 °C, zirconium is a solid. It melts at 1854.8 °C.
What is zirconium used for?
Key uses include: nuclear fuel-rod cladding; chemical plant equipment; ceramic knives and dental crowns (zirconia).
Related elements
Keep working with this element
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