Silver selenocyanates

The formation of aqueous silver(I)-selenocyanate complexes has been characterised in two restricted studies by Toropova [56TOR], and by Golub and Pomerants 

A salt of low solubility is also formed in the system according to the reaction Ag + SeCN AgSeCN(cr). (V. 121) 

This phase was first described by Birkenbach and Huttner [30BIR/HUT], who also estimated its aqueous solubility product from a one-point determination of [Ag ] in a saturated AgSeCN suspension to be log (AgSeCN, cr, 291 K) = — 15.4. 

Satyanarayama and Misra [74DAS/SAH] have more recently conducted a systematic study of the potential of the cell 

The Gibbs energy change corresponds to a solubility product for AgSeCN of  

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Silver Selenocyanate, AgCNSe, is obtained as a white precipitate closely resembling silver chloride by the action of silver nitrate on a solution of potassium selenocyanate. If, however, ammonia is previously added in excess to the silver nitrate solution, the selenocyanate is precipitated in minute satin-like crystals. 

Silver selenocyanate is readily blackened by the action of light. It is insoluble in water and only very sparingly soluble in ammonia and cold dilute acids. It is decomposed by boiling concentrated acids with the deposition of selenium, unless the acid used has oxidising properties. 

The selenocyanate ion is much less stable than the thiocyanate ion. However, silver selenocyanate complexes are in general more stable than the corresponding thiocyanates.148 Complex species of the type [Ag(SeCN) ]1 rt and [Ag SeCN)]"-1 (n = 1-4) have been predicted from potentiometric and solubility studies in aqueous solution. 

Diorgano tellurium dihalides stirred with silver selenocyanate or potassium selenocyanate in chloroform or acetone produce diorgano tellurium bis[selenocyanates] 3. 

DAS/SAH] Das, R. C., Sahu, G., Satyanarayana, D., Misra, S. N., Silver-silver selenocyanate electrode determination of standard electrode potential, solubility product of AgSeCN and various thermodynamic parameters at 35, 40, 45 and 50°C, Electrochim. Acta, 19, (1974), 887-890. Cited on page 307. 

A number of compounds of the types RBiY2 or R2BiY, where Y is an anionic group other than halogen, have been prepared by the reaction of a dihalo- or halobismuthine with a lithium, sodium, potassium, ammonium, silver, or lead alkoxide (120,121), amide (122,123), a2ide (124,125), carboxylate (121,126), cyanide (125,127), dithiocarbamate (128,129), mercaptide (130,131), nitrate (108), phenoxide (120), selenocyanate (125), silanolate (132), thiocyanate (125,127), or xanthate (133). Dialkyl- and diaryUialobismuthines can also be readily converted to secondary bismuthides by treatment with an alkali metal (50,105,134) ... 

I - Alkyny lphenyl selenides. Benzeneselenenyl bromide and silver nitrite (1 equiv.) rcncl to form a reagent (presumably C6H5SeN02) that converts 1-alkynes into 1-nlkynyl phenyl selenides (equation I).1 The same reaction has been effected in generally lower yields with phenyl selenocyanate catalyzed by Cu(I).2 The products tire useful intermediates for regio- and stereoselective synthesis of vinyl selenides. 

Two representative examples of this behavior are reflected in two distinct different chemical systems, namely (a) copper deposition from an acid sulfate electrolyte containing the co-inhibitors PEG-C1 and a bi-functional catalytic species SPS-C1 [12, 136, 243, 264] and (b) silver deposition from a cyanide electrolyte where inhibition is provided by adsorption of silver cyanide species and catalysis is achieved through adsorption of selenocyanate, SeCN [72-75]. Similar behavior is evident in some electrolytes used for the deposition of bright soft gold films [121, 180, 255-261, 267]. 

The generality of the CEAC mechanism has been demonstrated by extension to at least two other chemical systems, selenocyanate catalyzed silver deposition from a cyanide electrolyte [72-75] and iodine catalyzed CVD of copper from Cu(I)(hfac) (vtms) and related compounds [15, 77]. As shown in Figure 2.40, a one-to-one correlation between the SeCN-coverage and the silver deposition rate was established... 

Dichlorosilicon phthalocyanine (XIX) is prepared from silicon tetrachloride and phthalonitrile in quinoline at 200°C 168,170). The blue-green crystals, which sublime readily at 430°C in vacuo, hydrolyze forming dihydroxysilicon phthalocyanine (XX) when refluxed with equal volumes of pyridine and aqueous ammonia (200). The corresponding difluorosilicon phthalocyanine is resistant to hydrolysis. Conversion of the chloride to the corresponding dicyanate, dithiocyanate, and diselenocyanate occurs upon reaction with the appropriate silver pseudohalide (178). The complexes are believed to involve nitrogen to silicon bonding in the case of the thiocyanate and selenocyanate. 

Silver Azide. Cyanide, Cyanamides, Cyanate Selenocyanate and Thiocyanate Argon... 

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