Sulfur imides, S8-n NH

Boroholte, K. Dehnicke, H. Goesmann and D. Fenske, Z. anorg. allg. Chem., 586, 159-65 (1990). 

In no case have adjacent NH groups been observed. 

S7NH is a stable pale-yellow compound, mp 113.5° the structure is closely related to that of cyc/o-Sg as shown in Fig. 15.43a. The proton is acidic and undergoes many reactions of which the following are typical (see also p. 729)  

The 3 isomeric compounds S6(NH)2 form stable colourless crystals and have the structures illustrated in Fig. 15.43b, c, and The 

5-isomers melt at 130°, 133°, and 155° respectively. The 1,3,5- and 1,3,6-triimides melt with decomposition at 128° and 133° (Fig. 15.43e and f). The tetraimide, S4(NH)4 (mp 145°) is structurally very similar (Fig. 15.43g) the N atoms are each essentially trigonal planar and the heterocycle is somewhat flattened, the distance between the planes of the 4 N atoms and 4 S atoms being only 57 pm. The influence of extensive intermolecular H-bonding on the structure has been studied by electron deformation density techniques. 

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