Synthesis, crystal structure, and advanced NMR characterization of a low temperature polymorph of SiSe2

摘要: A low temperature polymorphic modification of silicon diselenide was synthesized via solid-state reaction and its crystal structure determined by single X-ray diffraction. In contrast to the well-characterized high-temperature form SiSe2, where edge-sharing SiSe4 tetrahedra one-dimensional chains, in low-temperature polymorph two-dimensional puckered layers are formed edge- corner-sharing tetrahedra. Such rearrangements have a significant impact on electronic SiSe2 as revealed quantum chemical calculations optical spectroscopy. The experimentally indirect bandgap for is 2.00(5) eV. Multinuclear (77Se, 29Si) NMR spectroscopy combined with first principles applied characterize shift tensor parameters Si Se sites structure. These results will enable quantitative application 29Si 77Se future structural studies Si–Se glasses, whose structures consist both corner- SiSe4/2