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Praseodymium, 59 Pr Praseodymium Pronunciation (PRAY -zee-oh-DIM -ee-əm[ 1] ) Appearance grayish white Standard atomic weight A r, std (Pr) 7002140907660000000♠ 140.90766 (1)[ 2] Praseodymium in the periodic cairt
Atomic nummer (Z ) 59 Group group n/a Period period 6 Block f-block Element category Lanthanide Electron confeeguration [Xe ] 4f3 6s2 Electrons per shell 2, 8, 18, 21, 8, 2 Pheesical properties Phase at STP solit Meltin pynt 1208 K (935 °C, 1715 °F) Bylin pynt 3793 K (3520 °C, 6368 °F) Density (near r.t. ) 6.77 g/cm3 when liquid (at m.p. ) 6.50 g/cm3 Heat o fusion 6.89 kJ/mol Heat o vapourisation 331 kJ/mol Molar heat capacity 27.20 J/(mol·K) Vapour pressur
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
1771
1973
(2227)
(2571)
(3054)
(3779)
Atomic properties Oxidation states 0,[ 3] +1,[ 4] +2, +3 , +4, +5 (a mildly basic oxide) Electronegativity Pauling scale: 1.13 Atomic radius empirical: 182 pm Covalent radius 203±7 pm Colour lines in a spectral range Spectral lines o praseodymiumIther properties Naitural occurrence primordial Creestal structur hexagonal Speed o soond thin rod 2280 m/s (at 20 °C) Thermal expansion (r.t. ) (α, poly) 6.7 µm/(m·K) Thermal conductivity 12.5 W/(m·K) Electrical resistivity (r.t. ) (α, poly) 0.700 µ Ω·m Magnetic orderin paramagnetic [ 5] Young's modulus (α form) 37.3 GPa Shear modulus (α form) 14.8 GPa Bulk modulus (α form) 28.8 GPa Poisson ratio (α form) 0.281 Vickers haurdness 400 MPa Brinell haurdness 481 MPa CAS Nummer 7440-10-0 History Diskivery Carl Auer von Welsbach (1885) Main isotopes o praseodymium
Decay modes in parentheses hae been predictit, but hae nae yet been observed | references
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in
calc from C
diff
report
ref
C
935
—
—
K
1208
1208
0
F
1715
1715
0
WD
1208 ! 1208 kelvin
input
C: 935, K: 1208, F: 1715
comment
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in
calc from C
diff
report
ref
C
3520
—
—
K
3793
3790
3
delta
F
6368
6370
-2
delta
WD
3403 ! 3403 kelvin
input
C: 3520, K: 3793, F: 6368
comment
References
Thir references will appear in the airticle, but this list appears anerly on this page.
↑ "praseodymium" . Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public leebrar membership required.)
↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)" . Pure and Applied Chemistry . 88 (3): 265–91. doi :10.1515/pac-2015-0305 .
↑ Yttrium and all lanthanides except Ce, Pm, Eu, Tm, Yb have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev . 22 : 17–24. doi :10.1039/CS9932200017 .
↑ Chen, Xin; et al. (13 December 2019). "Lanthanides with Unusually Low Oxidation States in the PrB3– and PrB4– Boride Clusters". Inorganic Chemistry . 58 (1): 411–418. doi :10.1021/acs.inorgchem.8b02572 . PMID 30543295 .
↑ M. Jackson "Magnetism of Rare Earth" The IRM quarterly col. 10, No. 3, p. 1, 2000
↑ "praseodymium" . Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public leebrar membership required.)