Palladium

Description	Palladium on carbon, often referred to as Pd/C, is a form of palladium used as a catalyst. The metal is supported on activated carbon in order to maximize its surface area and activity.
IUPAC Name	palladium
Molecular Weight	106.42
Molecular Formula	Pd
Canonical SMILES	[Pd]
InChI	1S/Pd
InChI Key	KDLHZDBZIXYQEI-UHFFFAOYSA-N
Boiling Point	2963 °C
Melting Point	1555ºC
Density	1.025 g/mL at 25ºC
Solubility	Soluble in aqua regia and fused alkalies; insoluble in organic acids
Appearance	Powder
Application	Among the platinum group metals, palladium is the least noble metal, exhibiting greater reactivity than other metals of the group. The metal forms mostly bivalent compounds, although a small number of tetravalent and a fewer trivalent compounds are known. Palladium exhibits a strong tendency to form complexes, most of which are four-coordinated square planar complexes of the metal in +2 oxidation state. When heated in air or oxygen above 350°C, palladium forms a black oxide, PdO coated over its surface. On further heating to over 790°C, the oxide decomposes back to the metal. Palladium dissolves more oxygen in molten state than in solid form. Palladium reacts with fluorine and chlorine at 500°C forming its halides, the black PdF3 and the red deliquescent solid PdCl2. Palladium is attacked by concentrated nitric acid, particularly in the presence of nitrogen oxides. The reaction is slow in dilute nitric acid. Finely divided palladium metal reacts with warm nitric acid forming palladium(II) nitrate, Pd(NO3)2. Hydrochloric acid has no affect on the metal. Reaction with boiling sulfuric acid yields palladium sulfate, PdSO4, and sulfur dioxide. Palladium readily dissolves in aqua regia forming chloropalladic acid, H2PdCl6. Evaporation of this solution yields palladium(II) chloride, PdCl2. Palladium absorbs hydrogen over 800 times its own volume over a range of temperature. By doing so, the metal swells, becoming brittle and cracked. Such absorption of hydrogen decreases the electrical conductivity of the metal. Also, such absorption activates molecular hydrogen, dissociating it to atomic hydrogen.
Storage	room temp
Assay	99.995% trace metals basis
EC Number	231-115-6
Fluorescence	1S/Pd
Form	powder
MDL Number	MFCD00011167
Packaging	1 g in glass bottle
Quality Level	100
Vapor Pressure	3.47 Pa (0.0260 mm Hg) at 1552 °C