Palladium (II) oxide

Crystal structure
	__ Pd 2+ __ O 2−
General
Surname	Palladium (II) oxide
other names	Palladium oxide; Palladium monoxide;
Ratio formula	PdO
Brief description	Greenish black, odorless powder
External identifiers / databases
EC number	215-218-3
ECHA InfoCard	100.013.836
PubChem	73974
Wikidata	Q421063
properties
Molar mass	122.42 g mol −1
Physical state	firmly
density	8.3 g cm −3
Melting point	750 ° C (decomposition)
solubility	almost insoluble in water and acids
safety instructions
GHS labeling of hazardous substances danger
H and P phrases	H: 272
	P: 210-220-221-280
Thermodynamic properties
ΔH f 0	349.95 kJ / mol (gas); −0.09 kJ / mol (crystal);
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Palladium (II) oxide is the most stable oxide of palladium . It is a greenish black, crystalline solid that melts at 750 ° C.

Extraction and presentation

Palladium oxide is formed by heating sponge palladium in the presence of oxygen at 350 ° C. The oxide is obtained as a black powder. Especially for catalytic applications, it can also be obtained by heating a mixture of palladium (II) chloride and potassium or sodium nitrate at 600 ° C. with subsequent leaching of the water-soluble residue. The hydrate form can be obtained by precipitation of palladium (II) nitrate with sodium hydroxide solution . The brown oxide hydrate can be converted into the dehydrated form by heating. The solubility in acids decreases with decreasing water content.

properties

Physical Properties

Palladium (II) oxide is in the form of greenish black tetragonal crystals. It is insoluble in water and acids, but slightly soluble in aqua regia .

Chemical properties

Palladium (II) oxide decomposes above 750 ° C to form palladium metal. When alkali lye is added to solutions containing palladium (II), yellow-brown palladium (II) oxide hydrate PdO · x H ₂ O is precipitated , which cannot be dehydrated without the simultaneous release of oxygen. In contrast to anhydrous PdO, it is soluble in acids.

use

Palladium oxide is used for the production of palladium hydrogenation catalysts by reduction with hydrogen .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Simon Cotton: The Chemistry of Precious Metals , Springer 1997.
↑ Data sheet palladium (II) oxide (PDF) from Merck , accessed on February 24, 2013.
↑ ^a ^b Datasheet Palladium (II) oxide (85% Pd), Palladium (II) oxide (85% Pd) hydrogenation catalyst for synthesis. CAS 1314-08-5, EC Number 215-218-3, chemical formula PdO. at Sigma-Aldrich , accessed December 7, 2019 ( PDF ).
^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 91st – 100th, improved and greatly expanded edition. Walter de Gruyter, Berlin 1985, ISBN 3-11-007511-3 .

[Cotton-1] ↑ ^a ^b ^c ^d ^e ^f ^g Simon Cotton: The Chemistry of Precious Metals , Springer 1997.

[merck-2] Data sheet palladium (II) oxide (PDF) from Merck , accessed on February 24, 2013.

[Sigma-3] Datasheet Palladium (II) oxide (85% Pd), Palladium (II) oxide (85% Pd) hydrogenation catalyst for synthesis. CAS 1314-08-5, EC Number 215-218-3, chemical formula PdO. at Sigma-Aldrich , accessed December 7, 2019 ( PDF ).

[Holleman-4] AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 91st – 100th, improved and greatly expanded edition. Walter de Gruyter, Berlin 1985, ISBN 3-11-007511-3 .