SeCl2 Selenium

SeCl2 Selenium (II) chloride, 5 127 [SeCl3]+[AlCl4]- Selenium (IV) chloride, compound with aluminum chloride, 6 127 SeCl4 Selenium (IV) chloride, 5 125, 126... 

Selenium dichloride, SeCl2, is only stable in the gas phase. 

Selenium analogues RN=SeCl2 are unknown for R = aryl or alkyl and thermally unstable when R = CE3 or C2E5. The perfluoroalkyl derivatives are prepared by the reaction of dichloroamino compounds and Sc2Cl2 in CCI3E (Eq. 8.18), but they decompose at room temperature to the corresponding diazene and a mixture of selenium chlorides. 

A more versatile synthesis of 11.1 (and the selenium analogue) involves the cyclocondensation of trisilylated amidines with sulfur dichloride or SeCl2 generated in situ (Eq. 11.3). This route can be used to prepare the prototypal systems [HCNEEN]" (E = S, Se). It is also readily extended to the synthesis of multi-dichalcogenadiazolium cations such as 1,3- or 1,4-C6H4(CNEEN)2] (H-2, E = S, Se), °... 

The 15-membered ring Se9(N Bu)6 (6.9) is a unique member of the series of cyclic chalcogen imides (see Section 12.8.1). It was first obtained as the major product of the reaction of LiN( Bu)SiMe3 with Se2Cl2 or SeOCl2. It is also formed, in addition to smaller cyclic selenium imides, in the cyclocondensation of SeCl2 with er -butylamine in THF or from the decomposition of the sele-nium(IV) diimide BuN=Se=N Bu. ... 

The production of these compounds is considered to be evidence of the unsymmetrical structure, Se SeCl2, for selenium monochloride. 

This occurs when equimolecular quantities of selenium chloride (SeCl2) and phenyl-j8-naphthylamine are condensed in benzene solution. It crystallises as small, yellow, bushy needles, M.pt. 176° C., readily soluble in boiling benzene or boiling alcohol, sparingly soluble in cold acetic acid. 

Selenium monochloride reacts with antipyrine1 as though it were 66 selenoselenyl dichloride, Se SeCl2. When a concentrated solution of the chloride in carbon tetrachloride is added to a concentrated solution of antipyrine in chloroform at 0° C., diantipyryl diselenide (or selenoselenide) is deposited,... 

By symproportionation of elemental selenium and SeCLi in polar protic solvents, [SeCLt] and [Se2Cl6] can be stabilized. They crystallize with voluminous organic cations (with SeCl2 RCl ratios of 1 2 and 1 1) (equations 43-45). 

Skinner has deduced E Sc - Se) from Se<3(g) to be 41 kcal. On the other hand wc may note that (Se - Se) is equal to the difference between the heats of atomization of Se2Cl2 and SeCl2, which is approximately 50 kcal, using our value of the heat of atomization of selenium. The heats of formation are perhaps not very certainly known.38 and we have had to estimate the heat of vaporization of Se2Ci2. 

FER/HAA] Fernholt, L., Haaland, A., Seip, R., Kniep, R., Korte, L., The molecular structure of selenium dichloride, SeCl2, determined by gas electron diffraction, Z Naturforsch, B Chem. ScL, 38b, (1983), 1072-173. Cited on page 169. 

In contrast to sulfur chemistry where dihalides are well established, the isolation of dihalides of selenium and tellurium has only been achieved for SeCl2 and SeBr2 (reactions 15.71 and 15.72). Selenium dichloride is a thermally unstable red oil SeBr2 is a red-brown solid. 

---