{{Chembox <!-- Images --> <!-- Names --> |IUPACName = Palladium |OtherNames = Palladium black <!-- Sections --> |Section1 = {{Chembox Identifiers |CASNo = 7440-05-3 | ChEBI = 33363 | ChemSpiderID = 22380 |PubChem = 23938 |SMILES = [Pd] |UNII = 5TWQ1V240M |EC_number = 231-115-6 |InChI = 1S/Pd |InChIKey = KDLHZDBZIXYQEI-UHFFFAOYSA-N }} |Section2 = {{Chembox Properties |Formula = Pd |MolarMass = 106.42 |Appearance = Black powder |SolubleOther = Organic solvents }} }}
'''Palladium black''' is a coarse, sponge-like form of elemental palladium which offers a large surface area for catalytic activity. It is used in organic synthesis as a catalyst for hydrogenation reactions.<ref name=Shigeo>{{cite book|last1=Nishimura|first1=Shigeo|title=Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis|date=2001|publisher=Wiley-Interscience|location=New York|isbn=9780471396987|pages=34–35|edition=1st|url=https://books.google.com/books?id=RjZRAAAAMAAJ&q=0471396982}}</ref>
The term palladium black is also used colloquially to refer to a black precipitate of elemental palladium, which forms via decomposition of various palladium complexes.<ref>{{Cite journal|last1=Iwasawa|first1=Tetsuo|last2=Tokunaga|first2=Makoto|last3=Obora|first3=Yasushi|last4=Tsuji|first4=Yasushi|date=2004-06-01|title=Homogeneous Palladium Catalyst Suppressing Pd Black Formation in Air Oxidation of Alcohols|journal=Journal of the American Chemical Society|volume=126|issue=21|pages=6554–6555|doi=10.1021/ja031936l|pmid=15161274|bibcode=2004JAChS.126.6554I |issn=0002-7863}}</ref>
==Preparation== Palladium black is typically prepared from palladium(II) chloride or palladium(II)-ammonium chloride.<ref name=Shigeo /> The palladium chloride process entails the formation of palladium hydroxide using lithium hydroxide followed by reduction under hydrogen gas<ref>{{cite journal|last1=Nishimura|first1=Shigeo|last2=Itaya|first2=Takashi|last3=Shiota|first3=Michio|title=Reactions of cycloalkanones in the presence of platinum-metal catalysts and hydrogen|journal=Chemical Communications|date=1967|issue=9|pages=422–423|doi=10.1039/C19670000422}}</ref> while the palladium(II)-ammonium chloride route employs a solution of formic acid followed by the precipitation of the catalyst using potassium hydroxide.<ref>{{cite journal|last1=Zelinsky|first1=N.|last2=Glinka|first2=N.|title=Über gleichzeitige Reduktions- und Oxydationskatalyse|journal=Berichte der Deutschen Chemischen Gesellschaft|date=1911|volume=44|issue=3|pages=2305–2311|doi=10.1002/cber.19110440347|url=https://zenodo.org/record/1426459}}</ref>
==See also== *Platinum black *Platinum dioxide *Platinum on carbon *Palladium on carbon *Rhodium-platinum oxide
==References== {{reflist}}
Category:Palladium Category:Hydrogenation catalysts