Structure of Amorphous Selenium by 2D 77Se NMR Spectroscopy: An End to The Dilemma of Chain vs. Ring
 

Structure of Amorphous Selenium by 2D 77Se NMR Spectroscopy: An End to The Dilemma of Chain vs. Ring


Amorphous selenium, owing to its tremendous technological importance and perhaps to its chemical simplicity, has been studied for nearly a century and yet an unequivocal structural description of this material remains lacking in the literature to date. The primary controversy regarding the structure of a-Se relates to the relative fraction of Se atoms residing in infinite (Se) chains vs. in Se8 rings. Here we present the results of a two-dimensional solid-state 77Se nuclear magnetic resonance (NMR) spectroscopic study of the chain and ring crystalline allotropes of Se as well as of amorphous Se to unequivocally demonstrate that (i) the Se8 rings and the infinite (Se) chains are characterized by their unique 77Se NMR signatures and (ii) the structure of amorphous Se consists exclusively of infinite (Se) chains.

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