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| Zirconium |
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| Pronunciation | (zur-KOH-nee-əm) |
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| Appearance | sillery white |
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| Standard atomic weight Ar, std(Zr) | 7001912240000000000♠91.224(2)[1] |
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| Zirconium in the periodic cairt |
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| Atomic nummer (Z) | 40 |
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| Group | group 4 |
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| Period | period 5 |
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| Block | d-block |
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| Element category | Transeetion metal |
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| Electron confeeguration | [Kr] 4d2 5s2 |
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| Electrons per shell | 2, 8, 18, 10, 2 |
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| Pheesical properties |
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| Phase at STP | solit |
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| Meltin pynt | 2128 K (1855 °C, 3371 °F) |
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| Bylin pynt | 4682 K (4409 °C, 7968 °F) |
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| Density (near r.t.) | 6.52 g/cm3 |
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| when liquid (at m.p.) | 5.8 g/cm3 |
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| Heat o fusion | 14 kJ/mol |
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| Heat o vapourisation | 573 kJ/mol |
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| Molar heat capacity | 25.36 J/(mol·K) |
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Vapour pressur| P (Pa) | 1 | 10 | 100 | 1 k | 10 k | 100 k |
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| at T (K) | 2639 | 2891 | 3197 | 3575 | 4053 | 4678 |
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| Atomic properties |
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| Oxidation states | −2, +1,[2] +2, +3, +4 (an amphoteric oxide) |
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| Electronegativity | Pauling scale: 1.33 |
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| Atomic radius | empirical: 160 pm |
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| Covalent radius | 175±7 pm |
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 Colour lines in a spectral rangeSpectral lines o zirconium |
| Ither properties |
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| Naitural occurrence | primordial |
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| Creestal structur | hexagonal close-packed (hcp) |
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| Speed o soond thin rod | 3800 m/s (at 20 °C) |
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| Thermal expansion | 5.7 µm/(m·K) (at 25 °C) |
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| Thermal conductivity | 22.6 W/(m·K) |
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| Electrical resistivity | 421 n Ω·m (at 20 °C) |
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| Magnetic orderin | paramagnetic[3] |
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| Young's modulus | 88 GPa |
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| Shear modulus | 33 GPa |
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| Bulk modulus | 91.1 GPa |
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| Poisson ratio | 0.34 |
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| Mohs haurdness | 5.0 |
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| Vickers haurdness | 903 MPa |
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| Brinell haurdness | 650 MPa |
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| CAS Nummer | 7440-67-7 |
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| History |
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| Diskivery | Martin Heinrich Klaproth (1789) |
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| First isolation | Jöns Jakob Berzelius (1824) |
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| Main isotopes o zirconium |
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| Isotope | Abundance | Hauf-life (t1/2) | Decay mode | Product |
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| 88Zr | syn | 83.4 d | ε | 88Y |
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| γ | - | 89Zr | syn | 78.4 h | ε | 89Y |
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| β+ | 89Y | | γ | - | | 90Zr | 51.45% | stable |
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| 91Zr | 11.22% | stable |
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| 92Zr | 17.15% | stable |
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| 93Zr | trace | 1.53×106 y | β− | 93Nb |
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| 94Zr | 17.38% | >1.1×1017 y | (β−β−) | 94Mo |
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| 96Zr | 2.8% | 2.0×1019 y[4] | β−β− | 96Mo |
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| Decay modes in parentheses are predictit, but hae nae yet been observed |
| | references |
