Element Zirconium

Zirconium ElementElement Zirconium is a chemical element with symbol Zr and atomic number 40. The name zirconium is taken from the name of the mineral zircon, the most important source of zirconium. The word zircon comes from the Persian word zargun زرگون, meaning “gold-colored”. It is a lustrous, grey-white, strong transition metal that resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Element Zirconium forms a variety of inorganic and organometallic compounds such as zirconium dioxide and zirconocene dichloride, respectively. Five isotopes occur naturally, three of which are stable. Element Zirconium compounds have no known biological role.

In powder form, zirconium is highly flammable, but the solid form is much less prone to ignition. Zirconium is highly resistant to corrosion by alkalis, acids, salt water and other agents.
However, it will dissolve in hydrochloric and sulfuric acid, especially when fluorine is present.
Alloys with zinc are magnetic at less than 35 K.

Names and Identifiers

Chemical Formula:Zr
CAS:7740-67-7
Molecular Weight:91.224 g/mol
EC Number :231-176-9
MDL Number:MFCD00011303
Color:Silvery white /grayish-white
Other Names:Zircat, Circonio, Zirconium Metal, Zirkonium
PubChem CID:23995
IUPAC Name:zirconium
Inchl:InChI=1S/Zr
InChI Key:QCWXUUIWCKQGHC-UHFFFAOYSA-N
Canonical SMILES:[Zr]
ICSC Number:1405

Physical & Chemical Properties

Phase:Solid
Density:1.01 g/mL at 25 °C
Boiling Point:4377 °C(lit.)
Melting Point:1852 °C(lit.)
Molecular Formula:Zr
Flash Point:n/a
Exact Mass:89.90470
Symbol:Globally Harmonized System of Classification
Signal Word:Danger
Hazard Statements:H250-H260
Precautionary Statements:P222-P223-P231 + P232-P370 + P378-P422
Hazard Codes:F: Flammable;Xi: Irritant;
Risk Phrases:R17
Safety Phrases:S26-S43-S7/8-S36-S36/37/39-S35-S27-S16
RIDADR:UN 2858 4.1/PG 3
WGK Germany:2
RTECS:ZH7070000
Packaging Group:III
Hazard Class:4.2
Naturally occurring zirconium (40Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (96Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×1019 years; it can also undergo single beta decay, which is not yet observed, but the theoretically predicted value of t1/2 is 2.4×1020 years. The second most stable radioisotope is 93Zr, which has a half-life of 1.53 million years. Twenty-seven other radioisotopes have been observed. All have half-lives less than a day except for 95Zr (64.02 days), 88Zr (83.4 days), and 89Zr (78.41 hours). The primary decay mode is electron capture for isotopes lighter than 92Zr, and the primary mode for heavier isotopes is beta decay.

Naturally occurring isotopes

IsotopeMass/DaNatural abundance (atom %)Nuclear spin (I)Magnetic moment (μ/μN)
90Zr89.9047026 (26)51.45 (40)0
91Zr90.9056439 (26)11.22 (5)5/2-1.30362
92Zr91.9050386 (26)17.15 (8)0
94Zr93.9063148 (28)17.38 (28)0
96Zr95.908275 (4)2.80 (9)0

Radiosotope data

IsotopeMass/DaHalf-lifeMode of decayNuclear spinNuclear magnetic moment
86Zr85.9164716.5 hEC to 86Y0
87Zr86.914821.73 hEC to 87Y9/2
88Zr87.9102383.4 dEC to 88Y0
89Zr88.9088893.27 dEC to 89Y9/2
93Zr92.9064741.5 x 106 yβ to 93Nb5/2
95Zr94.90804164.02 dβ to 95Nb5/2
96Zr95.9082763.9 x 1019 y to 96Mo0
97Zr96.91095016.8 hβ to 97Nb1/2

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