Tetraselenium tetranitride

     Among the compounds formed by Se and N, we mention only Se analogues of S₄N₄. Selenium tetranitride, Se₄N₄, can be prepared by reacting SeCl₄ with {(Me₃Si)₂N}₂Se. It forms orange, hygroscopic crystals and is highly explosive. The structure of Se4N4 is like that of S₄N₄ (15.59) with Se_N bond lengths of 180pm and cross-cage Se^……Se separations of 276pm (compare with r_cov)Se( = 117 pm). The reactivity of Se₄N₄ has not been as fully explored as that of S₄N₄. Reaction 15.118 is an adaptation of the synthesis of Se₄N₄ and leads to the 1,5-isomer of Se₂S₂N₄ (1.1). In the solid state structure, the S and Se atoms are disordered making it difficult to tell whether the crystalline sample is Se₂S₂N₄ or a solid solution of S₄N₄ and Se₄N₄. Mass spectrometric data are consistent with the presence of Se₂S₂N₄, and the appearance of only one signal in the ¹⁴N NMR spectrum confirms the 1,5- rather than 1,3-isomer.

          (1.1)

(1.1)