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About Palladium

Palladium Bohr

Palladium is one of six platinum-group metals, discovered by William Hyde Wollaston in 1802 as he attempted to process platina deposits into workable platinum metal. He named the new element after the also freshly discovered asteroid Pallas, and he initially made the strange decision to offer it for sale anonymously through distribution of an advertisement in 1803 but later disclosed his discovery officially in a scientific publication.

Palladium is similar to other platinum group elements in that it is a silvery metal that is relatively non-reactive, but of the group it has the lowest melting point and is the least dense. In its applications it is most similar to platinum: useful in metallic form for the production of a variety of products and as a catalyst. Palladium catalyzes reactions involved in petroleum cracking, water treatment, nitric acid production, and polymer manufacturing, and is found in catalytic converters and fuel cells as a catalyst. Additionally, palladium is used to increase the rate of hydrogenation and dehydrogenation reactions, and serves many specialized catalytic functions in organic chemistry. In fact, the 2010 Nobel Prize in Chemistry was given for the development of palladium-catalysed reactions used in organic synthesis. As a metal, palladium is used in in electronics for plating of components, electrical contacts, and solder, and is also found in jewelry, watches, blood sugar test strips, and surgical instruments. Alloyed with silver, palladium is used as electrodes in the production of multilayer ceramic capacitors. Finally, a niche use of both platinum and palladium salts is in the production of fine-art black and white photographic prints with the platinotype process.

Some other uses of palladium rely on chemistry unshared with platinum. Several of these involve useful interactions platinum has with hydrogen. As a gas, hydrogen easily diffuses through heated palladium, and thus palladium is used in the production of high purity hydrogen. Palladium also absorbs hydrogen gas, forming palladium hydride. This property is being researched for insights regarding hydrogen storage. Palladium chloride efficiently oxidizes carbon monoxide, and is used in detectors for the toxic but odorless gas. Additionally, radioactive palladium is under investigation for use in cancer treatment.

Like other platinum group metals, palladium is typically obtained for commercial use as a byproduct from nickel and copper mining and processing, but can also be obtained from ores rich in platinum and from alluvial deposits. Along with ruthenium and rhodium, palladium is a decomposition product of uranium and could theoretically be recovered from spent nuclear fuel, but the problems inherent in working with radioactive materials make this an impractical source for the rare element.

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Organometallics

Palladium is frequently alloyed with gold, silver, iridium and other platinum group elements for use in jewelry. The metal is used in surgical instruments and electrical contacts. Palladium is also an excellent hydrogenation and dehydrogenation catalyst and is available in many organometallic forms for this purpose. High Purity (99.999%) Palladium Oxide (PdO) PowderPalladium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. High Purity (99.999%) Palladium (Pd) Sputtering Target Palladium nanoparticles and nanopowders provide ultra-high surface area. Palladium oxide is available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Palladium fluoride is another insoluble palladium source for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Palladium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Palladium Properties

Palladium(Pd) atomic and molecular weight, atomic number and elemental symbolPalladium is a Block D, Group 10, Period 5 element. Palladium Bohr ModelThe number of electrons in each of palladium's shells is 2, 8, 18, 18 and its electron configuration is [Kr] 4d10. The palladium atom has a radius of 137.6.pm and its Van der Waals radius is 163.pm. In its elemental form, CAS 7440-05-3, palladium has a silvery white appearance. Elemental PalladiumPalladium is a member of the platinum group of metals (along with platinum, rhodium, ruthenium, iridium and osmium). Palladium has the lowest melting point and is the least dense of the group. Palladium can occurs as a natural alloy with other platinum-group metals. Nickel-copper deposits are the main commercial source of palladium. Palladium was first discovered by William Hyde Wollaston in 1802.

Symbol: Pd
Atomic Number: 46
Atomic Weight: 106.42
Element Category: transition metal
Group, Period, Block: 10, 5, d
Color: silvery white metallic/ silvery-white
Other Names: Palladio
Melting Point: 1554.9 °C, 2830.82 °F, 1828.05 K
Boiling Point: 2963 °C, 5365 °F, 3236 K
Density: 12.023 g·cm3
Liquid Density @ Melting Point: 10.38 g·cm3
Density @ 20°C: 12.02 g/cm3
Density of Solid: 12023 kg·m3
Specific Heat: 0.24 (kJ/kg K)
Superconductivity Temperature: N/A
Triple Point: 1825 K, 3.5 × 10 3 kPa
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 17.2
Heat of Vaporization (kJ·mol-1): 361.5
Heat of Atomization (kJ·mol-1): 377.4
Thermal Conductivity: 71.8 W·m?1·K?1
Thermal Expansion: (25 °C) 11.8 µm·m-1·K-1
Electrical Resistivity: (20 °C) 105.4 nΩ·m
Tensile Strength: N/A
Molar Heat Capacity: 25.98 J·mol-1·K-1
Young's Modulus: 121 GPa
Shear Modulus: 44 GPa
Bulk Modulus: 180 GPa
Poisson Ratio: 0.39
Mohs Hardness: 4.75
Vickers Hardness: 461 MPa
Brinell Hardness: 310 MPa
Speed of Sound: (20 °C) 3070 m·s-1
Pauling Electronegativity: 2.2
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.35
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 1.8
Reflectivity (%): 72
Refractive Index: N/A
Electrons: 46
Protons: 46
Neutrons: 60
Electron Configuration: [Kr] 4d10
Atomic Radius: 137 pm
Atomic Radius,
non-bonded (Å):
2.1
Covalent Radius: 139±6 pm
Covalent Radius (Å): 1.3
Van der Waals Radius: 163 pm
Oxidation States: 0, +1, +2, +4, +6 (mildly basic oxide)
Phase: Solid
Crystal Structure: face-centered cubic
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 54.206
1st Ionization Energy: 520.23 kJ·mol-1
2nd Ionization Energy: 7298.22 kJ·mol-1
3rd Ionization Energy: 11815.13 kJ·mol-1
CAS Number: 5/3/7440
EC Number: 231-115-6
MDL Number: MFCD00011167
Beilstein Number: N/A
SMILES Identifier: [Pd]
InChI Identifier: InChI=1S/Pd
InChI Key: KDLHZDBZIXYQEI-UHFFFAOYSA-N
PubChem CID: 23938
ChemSpider ID: 22380
Earth - Total: 0.89 ppm
Mercury - Total: 1.79 ppm
Venus - Total: 0.87 ppm
Earth - Seawater (Oceans), ppb by weight: N/A
Earth - Seawater (Oceans), ppb by atoms: N/A
Earth -  Crust (Crustal Rocks), ppb by weight: 6.3
Earth -  Crust (Crustal Rocks), ppb by atoms: 1
Sun - Total, ppb by weight: 3
Sun - Total, ppb by atoms: 0.04
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: 670
Meterorite (Carbonaceous), ppb by atoms: 130
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: N/A
Universe, ppb by atom: N/A
Discovered By: William Hyde Wollaston
Discovery Date: 1803
First Isolation: William Hyde Wollaston (1803)

Health, Safety & Transportation Information for Palladium

Safety data for Palladium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) palladium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word N/A
Hazard Statements N/A
Hazard Codes N/A
Risk Codes N/A
Safety Precautions N/A
RTECS Number N/A
Transport Information N/A
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)
N/A

Palladium Isotopes

Naturally occurring palladium (Pd) has four stable isotopes: 104Pd, 105Pd, 106Pd, and 108Pd.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
91Pd 90.94911(61)# 10# ms [>1.5 µs] ß+to 91Rh 7/2+# N/A 731.06 -
92Pd 91.94042(54)# 1.1(3) s [0.7(+4-2) s] ß+to 92Rh 0+ N/A 747.52 -
93Pd 92.93591(43)# 1.07(12) s ß+to 93Rh (9/2+) N/A 760.26 -
94Pd 93.92877(43)# 9.0(5) s ß+to 94Rh 0+ N/A 774.86 -
95Pd 94.92469(43)# 10# s ß+to 95Rh 9/2+# N/A 786.67 -
96Pd 95.91816(16) 122(2) s ß+to 96Rh 0+ N/A 800.33 -
97Pd 96.91648(32) 3.10(9) min ß+to 97Rh 5/2+# N/A 810.28 -
98Pd 97.912721(23) 17.7(3) min ß+to 98Rh 0+ N/A 822.08 -
99Pd 98.911768(16) 21.4(2) min ß+to 99Rh (5/2)+ N/A 831.09 -
100Pd 99.908506(12) 3.63(9) d EC to 100Rh 0+ N/A 841.97 -
101Pd 100.908289(19) 8.47(6) h EC to 101Rh 5/2+ -0.66 857.5 -
102Pd 101.905609(3) Observationally Stable - 0+ N/A 865.58 1.02
103Pd 102.906087(3) 16.991(19) d EC to 103Rh 5/2+ N/A 873.66 -
104Pd 103.904036(4) STABLE - 0+ N/A 881.73 11.14
105Pd 104.905085(4) STABLE - 5/2+ -0.642 889.81 22.33
106Pd 105.903486(4) STABLE - 0+ N/A 897.89 27.33
107Pd 106.905133(4) 6.5(3)E+6 y ß- to 107Ag 5/2+ N/A 905.97 -
108Pd 107.903892(4) STABLE - 0+ N/A 914.05 26.46
109Pd 108.905950(4) 13.7012(24) h ß- to 109Ag 5/2+ N/A 922.13 -
110Pd 109.905153(12) Observationally Stable - 0+ N/A 930.21 11.72
111Pd 110.907671(12) 23.4(2) min ß- to 111Ag 5/2+ N/A 938.28 -
112Pd 111.907314(19) 21.03(5) h ß- to 113Ag 0+ N/A 946.36 -
113Pd 112.91015(4) 93(5) s ß- to 114Ag (5/2+) N/A 945.13 -
114Pd 113.910363(25) 2.42(6) min ß- to 115Ag 0+ N/A 953.2 -
115Pd 114.91368(7) 25(2) s ß- to 116Ag (5/2+)# N/A 961.28 -
116Pd 115.91416(6) 11.8(4) s ß- to 117Ag 0+ N/A 969.36 -
117Pd 116.91784(6) 4.3(3) s ß- to 118Ag (5/2+) N/A 977.44 -
118Pd 117.91898(23) 1.9(1) s ß- to 119Ag 0+ N/A 985.52 -
119Pd 118.92311(32)# 0.92(13) s ß- to 120Ag N/A N/A 984.28 -
120Pd 119.92469(13) 0.5(1) s ß- to 121Ag 0+ N/A 992.36 -
121Pd 120.92887(54)# 400# ms [>300 ns] ß- to 122Ag N/A N/A 1000.44 -
122Pd 121.93055(43)# 300# ms [>300 ns] ß- to 123Ag 0+ N/A 999.2 -
123Pd 122.93493(64)# 200# ms [>300 ns] ß- to 124Ag N/A N/A 1007.28 -
124Pd 123.93688(54)# 100# ms [>300 ns] Unknown 0+ N/A 1015.36 -
125Pd 125 0.44(3) µs / 0.33(4) µs
(2 isomers)
Unknown N/A N/A N/A -
126Pd 126 5.8(8) µs Unknown N/A N/A N/A -
Palladium Elemental Symbol

Recent Research & Development for Palladium

  • Palladium-Catalyzed Intramolecular Cyclization of Ynamides: Synthesis of 4-Halo-oxazolones. Huang H, He G, Zhu G, Zhu X, Qiu S, Zhu H. J Org Chem. 2015 Mar 16.
  • Monocarboxylation and Intramolecular Coupling of Butenylated Arenes via Palladium-Catalyzed C-H Activation Process. Liu R, Lu ZH, Hu XH, Li JL, Yang XJ. Org Lett. 2015 Mar 12.
  • Palladium-Catalyzed Cycloisomerization and Aerobic Oxidative Cycloisomerization of Homoallenyl Amides: A Facile and Divergent Approach to 2-Aminofurans. Cheng C, Liu S, Zhu G. Org Lett. 2015 Mar 12.
  • Exhibition of the Brønsted acid-base character of a Schiff base in palladium(ii) complex formation: lithium complexation, fluxional properties and catalysis of Suzuki reactions in water. Kumar R, Mani G. Dalton Trans. 2015 Mar 16.
  • Highly selective detection of palladium and picric acid by a luminescent MOF: a dual functional fluorescent sensor. Sanda S, Parshamoni S, Biswas S, Konar S. Chem Commun (Camb). 2015 Mar 16.
  • Palladium-Catalyzed Cs2CO3-Promoted Arylation of Unactivated C(sp3)-H Bonds by (Diacetoxyiodo)arenes: Shifting the Reactivity of (Diacetoxyiodo)arenes from Acetoxylation to Arylation. Gou Q, Zhang ZF, Liu ZC, Qin J. J Org Chem. 2015 Mar 12.
  • Frustrated Lewis pair-like reactions of nucleophilic palladium carbenes with B(C6F5)3. Cui P, Comanescu CC, Iluc VM. Chem Commun (Camb). 2015 Mar 10.
  • New palladium(ii) and platinum(ii) 5,5-diethylbarbiturate complexes with 2-phenylpyridine, 2,2'-bipyridine and 2,2'-dipyridylamine: synthesis, structures, DNA binding, molecular docking, cellular uptake, antioxidant activity and cytotoxicity. Icsel C, Yilmaz VT, Kaya Y, Samli H, Harrison WT, Buyukgungor O. Dalton Trans. 2015 Mar 16.
  • A Tris(triazolate) Ligand for a Highly Active and Magnetically Recoverable Palladium Catalyst of Selective Alcohol Oxidation Using Air at Atmospheric Pressure. Wang D, Deraedt C, Salmon L, Labrugère C, Etienne L, Ruiz J, Astruc D. Chemistry. 2015 Mar 9.
  • One pot synthesis of diarylfurans from aryl esters and PhI(OAc)2via palladium-associated iodonium ylides. Bao YS, Agula B, Zhaorigetu B, Jia M, Baiyin M. Org Biomol Chem. 2015 Mar 11.
  • A novel water-soluble ESIPT fluorescent probe with high quantum yield and red emission for ratiometric detectionto inorganic and organic palladium. Gao T, Xu P, Liu M, Bi A, Zeng W. Chem Asian J. 2015 Mar 10.
  • Reactions of phenylacetylene with nickel POCOP-pincer hydride complexes resulting in different outcomes from their palladium analogues. Wilson GL, Abraha M, Krause JA, Guan H. Dalton Trans. 2015 Mar 16.
  • Insights into the reaction mechanism of CO oxidative coupling to dimethyl oxalate over palladium: a combined DFT and IR study. Li Q, Zhou Z, Chen R, Sun B, Qiao L, Yao Y, Wu K. Phys Chem Chem Phys. 2015 Mar 11.
  • Palladium-catalyzed oxidative C-H/C-H cross-coupling of 1-substituted 1,2,3-triazoles with furans and thiophenes. Yu X, Huang Z, Liu W, Shi S, Kuang C. Org Biomol Chem. 2015 Mar 13.
  • Chemical Remodeling of Cell-Surface Sialic Acids through a Palladium-Triggered Bioorthogonal Elimination Reaction. Wang J, Cheng B, Li J, Zhang Z, Hong W, Chen X, Chen PR. Angew Chem Int Ed Engl. 2015 Mar 12.
  • Palladium Nanotubes Formed by Lipid Tubule Templating and Their Application in Ethanol Electrocatalysis. Wang Y, Ma S, Su Y, Han X. Chemistry. 2015 Mar 12.
  • Host-Guest Behavior of a Heavy-Atom Heterocycle Re4(CO)16(μ-SbPh2)2(μ-H)2 Obtained from a Palladium-Assisted Ring Opening Dimerization of Re2(CO)8(μ-SbPh2)(μ-H). Adams RD, Pearl WC Jr, Wong YO, Hall MB, Walensky JR. Inorg Chem. 2015 Mar 10.
  • Tackling poison and leach: catalysis by dangling thiol-palladium functions within a porous metal-organic solid. Gui B, Yee KK, Wong YL, Yiu SM, Zeller M, Wang C, Xu Z. Chem Commun (Camb). 2015 Mar 11.
  • Palladium-meta-Terarylphosphine Catalyst for the Mizoroki-Heck Reaction of (Hetero-)Aryl Bromides and Functional Olefins. Tay DW, Jong H, Lim YH, Wu W, Chew X, Robins EG, Johannes CW. J Org Chem. 2015 Mar 13.
  • Palladium(ii)-1-phenylthio-2-arylchalcogenoethane complexes: palladium phosphide nano-peanut and ribbon formation controlled by chalcogen and Suzuki coupling activation. Kumar Rao G, Kumar A, Saleem F, Singh MP, Kumar S, Kumar B, Mukherjee G, Singh AK. Dalton Trans. 2015 Mar 11.