Zirconium is the element of the periodic table with atomic number 40 and element symbol Zr. It is a ductile and malleable silver transition metal with high melting and boiling points. While you may not encounter the pure element, it occurs in familiar products, such as antiperspirants, cubic zirconia gemstones, ceramics, and dental implants. Here is a collection of zirconium facts, including its properties, uses, and sources.
Basic Zirconium Facts
Atomic Number: 40
Atomic Weight: 91.224
Group: group 4 (transition metal)
Period: period 5
Electron Configuration: [Kr] 4d2 5s2
Electrons per Shell: 2, 8, 18, 10, 2
Discovery: Martin Klaproth discovered zirconium from the mineral jargoon in 1785. Berzelius first purified the metal in 1824. But, biblical texts refer to zircon, hyacinth, jargoon, ligure, and jacinth, which are zirconium gems and minerals.
Name Origin: The element takes its name for the mineral zircon. The word zircon, in turn, comes from the Persian zargun, which means “golden.”
Isotopes: Natural zirconium consists of five isotopes. Four of these isotopes are stable and one is radioactive. The most common isotopes is zirconium-90, which is a stable isotope that accounts for 51.45% of the element. An additional 28 isotopes have been synthesized.
Biological Role and Toxicity: Zirconium serves no known biological role in humans, but it does not cause harm, either. A person’s body contains around 250 milligrams of the element. Dietary sources of zirconium include brown rice, whole wheat, spinach, eggs, beef. Zirconium is generally safe and non-toxic, although the metal powder and some compounds irritate skin. The metal is neither carcinogenic or genotoxic.
Uses: Zirconium compounds are more common than zirconium metal. Zirconium oxides find use as abrasives, ceramics, dental implants and crowns, and ceramics. Zircon and cubic zirconia are gemstones in jewelry. The most common use for pure zirconium is as a refractory metal. The most common alloy is zircaloy, which is used for cladding of nuclear reactor fuels. Zirconium oxides and zirconium metal are useful for high temperature applications, as in space vehicles, jet engine and gas turbine blades, and combustors. Zirconium binds urea, so it is helpful for managing chronic kidney disease. Zirconium carbonate treats poison ivy. A compound containing zirconium and aluminum (AZG) is a common antiperspirant that works by blocks pores in the skin. Other uses of zirconium include water purification, hyperkalemia treatment, knee and hip replacements, flashbulbs, sparklers, and superconducting magnets.
Sources: The element does not occur in pure form. It’s concentration is about 130 mg/kg in the Earth’s crust and 0.026 μg/L in sea water. Most zirconium comes from zircon (ZrSiO4) or as a by-product of mining titanium and tin minerals. Sources of zircon include Brazil, Russia, Australia, India, South Africa, and the United States. Smaller amounts of zirconium-rich minerals occur throughout the world.
Element Classification: Transition Metal
Density (g/cc): 6.52
Melting Point: 2125 K (1852 °C, 3365 °F)
Boiling Point: 4650 K (4377 °C, 7911 °F)
Appearance: grayish-white, lustrous, corrosion-resistant metal
Specific Heat (@20°C J/g mol): 0.281
Fusion Heat (kJ/mol): 14
Evaporation Heat (kJ/mol): 591
Debye Temperature (K): 250.00
Molar Heat Capacity: 25.36 J/(mol·K)
Lattice Structure: Hexagonal
Lattice Constant (Å): 3.230
Lattice C/A Ratio: 1.593
Zirconium is a member of the transition metals group of elements. Learn more about this large element group.
Atomic Radius (pm): 175
Atomic Volume (cc/mol): 14.1
Covalent Radius (pm): 145
Ionic Radius: 79 (+4e)
Pauling Electronegativity: 1.33
First Ionizing Energy (kJ/mol): 659.7
Oxidation States: -2, 0, +1, +2, +3, +4
Interesting Zirconium Facts
- Zirconium occurs elsewhere in the universe besides Earth. It’s in the Sun, S-type stars, and meteorites. Lunar rocks contain about the same amount of zirconium oxide as terrestrial rocks.
- Zirconium takes either of two crystal structures, which are named the alpha phase (α-Zr) and the beta phase (β-Zr). At room temperature, the atoms form close-packed hexagonal α-Zr. At 863 °C, the structure transitions to body-centered β-Zr.
- As with many metals, finely powdered zirconium is highly flammable.
- Although zirconium resists corrosion, it dissolves in hydrochloric acid or sulfuric acid.
- Alloys of zirconium and zinc are magnetic below temperatures of 35 K.
- In pyrotechnics, burning zirconium forms bright white sparks.
- Zirconium forms organometallic compounds. Organozirconium is a key catalyst in polypropylene (plastic) production.
- The compound zirconium tungstate displays the uncommon property of shrinking when heated.
- Zirconium salts usually burn with a pale red flame in a flame test.
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