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- Palladium(II)_cyanide abstract "Palladium(II) cyanides are chemical species with the empirical formula Pd(CN)n(2-n)-. The dicyanide (n = 2, CAS: [2035-66-7]) is a coordination polymer which was the first pure palladium compound isolated. In his attempts to produce pure platinum metal in 1804, W.H. Wollaston added mercuric cyanide to a solution of impure platinum metal in aqua regia to precipitate palladium cyanide which was then ignited to recover palladium metal - a new element. It had long been suspected that the structure of palladium cyanide consists of square planar Pd(II) centers linked by bridging cyanide ligands, which are bonded through both the carbon and nitrogen atoms. The CN stretch in the infrared spectra of Pd(CN)2, at 2222 cm−1, is typical of bridging cyanide ions. It is now known that the compound commonly known as "Palladium(II) cyanide" is in fact a nanocrystaline material better described using the formula Pd(CN)2.0.29H2O. The interior of the sheets do indeed consist of square-planar palladium ions linked by head-to-tail disordered bridging cyanide groups to form 4,4-nets. These sheets are approximately 3 nm x 3 nm in size and are terminated by an equal number of water and cyanide groups maintaining the charge neutrality of the sheets. These sheets then stack with very little long range order resulting in Bragg diffraction patterns with very broad peaks. The Pd-C and Pd-N bond lengths, determined using total neutron diffraction, are both 1.98 Å.The compound is rather insoluble in water with a solubility product of log Ksp = -42.The slightly more topical palladium(II) cyanide is the dianion [Pd(CN)4]2-. The equilibrium constant for the competition reactionPdL2+ + 4CN- [Pd(CN)4]2- + L, L = 1,4,8,11-tetraazaundecane (2,3,2-tet)was found to have a value of log K = 14.5. Combination with the formation of the palladium complex with the tetradentate ligand [Pd(H2O)4]2+ + L PdL2+ + 4 H2O, log K = 47.9gives[Pd(H2O)4]2+ + 4CN- [Pd(CN)4]2- + 4H2O, log β4 = 62.3.This appears to be the highest formation constant known for any metal ion.The affinity of Pd for cyanide is so great that palladium metal is attacked by cyanide solutions:Pd(s) + 2 H+ + 4 CN- [Pd(CN)4]2- + H2This reaction is reminiscent of the “cyanide process” for the extraction of gold, although in the latter reaction O2 is proposed to be involved, to give H2O.Exchange of between free cyanide ion and [Pd(CN)4]2- has been evaluated by 13C NMR spectroscopy. That exchange occurs at all illustrates the ability of some compounds to be labile (fast reactions) but also stable (high formation constants). The reaction rate is described as follows:rate = k2[M(CN)42-][CN-], where k2 120 M-1-s-1The bimolecular kinetics implicate a so-called associative pathway. The associative mechanism of exchange entails rate-limiting attack of cyanide on [Pd(CN)4]2-, possibly with the intermediacy of a highly reactive pentacoordinate species [Pd(CN)5]3-. By comparison, the rate constant for [Ni(CN)4]2- is > 500,000 M-1-s−1, whereas [Pt(CN)4]2-exchanges more slowly at 26 M−1s−1. Such associative reactions are characterized by large negative entropies of activation, in this case: -178 and -143 kJ/(mol·K) for Pd and Pt, respectively.In organic synthesis palladium cyanide is used in the synthesis of olefinic cyanides from olefins. and as a catalyst in the regioselective reaction between cyanotrimethylsilane and oxiranes .".
- Palladium(II)_cyanide iupacName "Palladium(2+) dicyanide".
- Palladium(II)_cyanide wikiPageID "4436162".
- Palladium(II)_cyanide wikiPageRevisionID "544323087".
- Palladium(II)_cyanide hasPhotoCollection Palladium(II)_cyanide.
- Palladium(II)_cyanide iupacname "Palladium dicyanide".
- Palladium(II)_cyanide subject Category:Cyanides.
- Palladium(II)_cyanide subject Category:Palladium_compounds.
- Palladium(II)_cyanide type Abstraction100002137.
- Palladium(II)_cyanide type Chemical114806838.
- Palladium(II)_cyanide type Cognition100023271.
- Palladium(II)_cyanide type Compound105870180.
- Palladium(II)_cyanide type Compound114818238.
- Palladium(II)_cyanide type Concept105835747.
- Palladium(II)_cyanide type Content105809192.
- Palladium(II)_cyanide type Cyanides.
- Palladium(II)_cyanide type Idea105833840.
- Palladium(II)_cyanide type Material114580897.
- Palladium(II)_cyanide type Matter100020827.
- Palladium(II)_cyanide type Nitrile114827346.
- Palladium(II)_cyanide type OrganicCompound114727670.
- Palladium(II)_cyanide type PalladiumCompounds.
- Palladium(II)_cyanide type Part113809207.
- Palladium(II)_cyanide type PhysicalEntity100001930.
- Palladium(II)_cyanide type PsychologicalFeature100023100.
- Palladium(II)_cyanide type Relation100031921.
- Palladium(II)_cyanide type Substance100019613.
- Palladium(II)_cyanide type Whole105869584.
- Palladium(II)_cyanide type ChemicalCompound.
- Palladium(II)_cyanide type ChemicalSubstance.
- Palladium(II)_cyanide type ChemicalObject.
- Palladium(II)_cyanide type Thing.
- Palladium(II)_cyanide comment "Palladium(II) cyanides are chemical species with the empirical formula Pd(CN)n(2-n)-. The dicyanide (n = 2, CAS: [2035-66-7]) is a coordination polymer which was the first pure palladium compound isolated. In his attempts to produce pure platinum metal in 1804, W.H. Wollaston added mercuric cyanide to a solution of impure platinum metal in aqua regia to precipitate palladium cyanide which was then ignited to recover palladium metal - a new element.".
- Palladium(II)_cyanide label "Palladium(II) cyanide".
- Palladium(II)_cyanide label "Цианид палладия(II)".
- Palladium(II)_cyanide sameAs m.0c28j0.
- Palladium(II)_cyanide sameAs Q4505501.
- Palladium(II)_cyanide sameAs Q4505501.
- Palladium(II)_cyanide sameAs Palladium(II)_cyanide.
- Palladium(II)_cyanide wasDerivedFrom Palladium(II)_cyanide?oldid=544323087.
- Palladium(II)_cyanide isPrimaryTopicOf Palladium(II)_cyanide.