![](//upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Praseodymium.jpg/220px-Praseodymium.jpg) |
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Pronunciation | [1] (PRAY-zee-ə-DIM-ee-əm) |
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Appearance | grayish white |
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| 140.90766(1)[2] |
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Atomic number (Z) | 59 |
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Group | f-block groups (no number) |
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Period | period 6 |
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Block | f-block |
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Electron configuration | [Xe] 4f3 6s2 |
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Electrons per shell | 2, 8, 18, 21, 8, 2 |
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Phase at STP | solid |
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Melting point | 1208 K (935 °C, 1715 °F) |
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Boiling point | 3403 K (3130 °C, 5666 °F) |
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Density (near r.t.) | 6.77 g/cm3 |
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when liquid (at m.p.) | 6.50 g/cm3 |
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Heat of fusion | 6.89 kJ/mol |
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Heat of vaporization | 331 kJ/mol |
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Molar heat capacity | 27.20 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
1771 |
1973 |
(2227) |
(2571) |
(3054) |
(3779) |
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Oxidation states | 0,[3] +1,[4] +2, +3, +4, +5 (a mildly basic oxide) |
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Electronegativity | Pauling scale: 1.13 |
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Ionization energies | - 1st: 527 kJ/mol
- 2nd: 1020 kJ/mol
- 3rd: 2086 kJ/mol
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Atomic radius | empirical: 182 pm |
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Covalent radius | 203±7 pm |
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Spectral lines of praseodymium |
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Natural occurrence | primordial |
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Crystal structure | double hexagonal close-packed (dhcp) |
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Speed of sound thin rod | 2280 m/s (at 20 °C) |
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Thermal expansion | α, poly: 6.7 µm/(m⋅K) (at r.t.) |
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Thermal conductivity | 12.5 W/(m⋅K) |
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Electrical resistivity | α, poly: 0.700 µΩ⋅m (at r.t.) |
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Magnetic ordering | paramagnetic[5] |
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Molar magnetic susceptibility | +5010.0×10−6 cm3/mol (293 K)[6] |
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Young's modulus | α form: 37.3 GPa |
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Shear modulus | α form: 14.8 GPa |
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Bulk modulus | α form: 28.8 GPa |
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Poisson ratio | α form: 0.281 |
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Vickers hardness | 250–745 MPa |
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Brinell hardness | 250–640 MPa |
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CAS Number | 7440-10-0 |
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Discovery | Carl Auer von Welsbach (1885) |
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Category: Praseodymium | references |