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sillery white
General properties
Name, seembol, nummer palladium, Pd, 46
Pronunciation /pəˈldiəm/
Element category transeetion metal
Group, period, block 10, 5, d
Staundart atomic wicht 106.42
Electron confeeguration [Kr] 4d10
2, 8, 18, 18
Electron shells of palladium (2, 8, 18, 18)
Namin after asteroid Pallas, itself named efter Pallas Athena
Discovery William Hyde Wollaston (1803)
First isolation William Hyde Wollaston (1803)
Physical properties
Phase solid
Density (near r.t.) 12.023 g·cm−3
Liquid density at m.p. 10.38 g·cm−3
Meltin pynt 1828.05 K, 1554.9 °C, 2830.82 °F
Boilin pynt 3236 K, 2963 °C, 5365 °F
Heat o fusion 16.74 kJ·mol−1
Heat o vaporization 362 kJ·mol−1
Molar heat capacity 25.98 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1721 1897 2117 2395 2753 3234
Atomic properties
Oxidation states 0, +1, +2, +4, +6
(mildly basic oxide)
Electronegativity 2.20 (Pauling scale)
Ionization energies 1st: 804.4 kJ·mol−1
2nd: 1870 kJ·mol−1
3rd: 3177 kJ·mol−1
Atomic radius 137 pm
Covalent radius 139±6 pm
Van der Waals radius 163 pm
Crystal structure face-centered cubic
Palladium has a face-centered cubic crystal structure
Magnetic orderin paramagnetic[1]
Electrical resistivity (20 °C) 105.4 nΩ·m
Thermal conductivity 71.8 W·m−1·K−1
Thermal expansion (25 °C) 11.8 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 3070 m·s−1
Young's modulus 121 GPa
Shear modulus 44 GPa
Bulk modulus 180 GPa
Poisson ratio 0.39
Mohs hairdness 4.75
Vickers hairdness 461 MPa
Brinell hairdness 310 MPa
CAS registry nummer 7440-05-3
Most stable isotopes
Main article: Isotopes o palladium
iso NA hauf-life DM DE (MeV) DP
100Pd syn 3.63 d ε - 100Rh
γ 0.084, 0.074,
102Pd 1.02% 102Pd is stable wi 56 neutrons
103Pd syn 16.991 d ε - 103Rh
104Pd 11.14% 104Pd is stable wi 58 neutrons
105Pd 22.33% 105Pd is stable wi 59 neutrons
106Pd 27.33% 106Pd is stable wi 60 neutrons
107Pd trace 6.5×106 y β 0.033 107Ag
108Pd 26.46% 108Pd is stable wi 62 neutrons
110Pd 11.72% >6×1017 y ββ - 110Cd
· r

Palladium is a chemical element wi the chemical seembol Pd an an atomic nummer o 46. It is a rare an lustrous sillery-white metal discovered in 1803 bi William Hyde Wollaston. He named it efter the asteroid Pallas, which wis itself named efter the epithet o the Greek goddess Athena, acquired bi her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium an osmium fairm a group o elements referred tae as the platinum group metals (PGMs). These hae seemilar chemical properties, but palladium haes the lawest meltin pynt an is the least dense o them.

Ower hauf o the supply o palladium an its congener platinum gangs intae catalytic converters, which convert up tae 90% o harmful gases frae auto exhaust (hydrocarbons, carbon monoxide, an nitrogen dioxide) intae less-harmful substances (nitrogen, carbon dioxide an watter vapor). Palladium is an aa uised in electronics, dentistry, medicine, hydrogen purification, chemical applications, groundwatter treatment an jewelry. Palladium plays a key role in the technology uised for fuel cells, which combine hydrogen an oxygen tae produce electricity, heat, an watter.

Ore deposits o palladium an ither PGMs are rare, an the maist extensive deposits hae been foond in the norite belt o the Bushveld Igneous Complex coverin the Transvaal Basin in Sooth Africae, the Stillwatter Complex in Montana, Unitit States, the Thunder Bay Destrict o Ontario, Canadae, an the Norilsk Complex in Roushie. Recyclin is an aa a soorce o palladium, maistly frae scrapped catalytic converters. The numerous applications an leemitit supply soorces o palladium result in the metal attractin considerable investment interest.

References[eedit | eedit soorce]

  1. Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5. 

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