Tetrasulfur tetranitride

Orange crystals ( 25 ° C)

Fixed

178.2 ° C

Insoluble in water

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Tetrasulfur is an inorganic chemical compound of the sulfur from the group consisting of the nitrides.

Production and representation

Tetrasulfur can be obtained with ammonia in dichloromethane followed by recrystallization in toluene by reaction of a mixture of sulfur ( II) chloride and sulfur ( I) chloride.

Also possible is the preparation by reaction of sulfur with the liquid ammonia in the presence of silver nitrate.

Properties

Tetrasulfur is one of the longest known cage compounds ( structure with D2d symmetry) and was first described in the year 1835. It tends to explosive decomposition and is thermochromic, meaning that it changes its color from colorless ( at 77 K), over bright orange ( at 298 K) to red ( at 373 K). When passing over gaseous tetrasulfur silver wool at 200 to 300 ° C, it passes into the annular dimer Dischwefeldinitrid S2N2. Tetrasulfur sublimated mbar below 130 ° C, pressure at 0.1. In water it is insoluble in alkalies and in acids with decomposition only with protonation. Solid tetrasulfur decomposes when heated above 130 ° C or in case of shock explosively into its elements (460 kJ / mol).

Gaseous tetrasulfur decomposes above 200 ° C mainly in Dischwefeldinitrid, which also form S3N3 and S4N2. Above 300 ° C and it decomposes in the elements and Schwefelmononitrid SN.

Use

Tetrasulfur is one of the major raw materials for the production of sulfur -nitrogen compounds such as the cyclic trimer of Thionitrosylchlorid or Tetraschwefeltetraimid.