Oxyhalides and thiohalides

The linear oxychlorides Si 0 iCl2n+2 have been prepared by passing a 

Whereas controlled hydrolysis of SiCl4 at —78°C gives the linear oxychlorides SinO iCl2 +2, a similar treatment of Si2Cl6 gives another series Si2 +20 Cl4 +6 containing pairs of linked Si atoms bonded into chains by 0 atoms  

In this way Si40Qio, Si602Cli4, and Si803Clig have been obtained as colourless liquids.  

Thiochlorides that have been prepared include Si2SQ5 (I), the cyclic compound (II). 

Electron diffraction studies have been made of tetramethyl cyclodisilthiane (a) and hexamethylcyclotrisilthiane (b)  

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Table 2 Representative List of Oxyhalide and Thiohalide Solvents and Some of Their Physical Properties (interesting as liquid cathodes and solvents for primary Li, Ca and Mg batteries)... 

Each trihalide may be made (although not necessarily most conveniently) by direct union of the elements. They will easily undergo atmospheric oxidation to the oxyhalide, add sulphur to form the thiohalide, hydrolyse under acid conditions to form phosphorous acid, readily add more halogen to form the pentahalide, and form addition complexes with various metals. 

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