Search

Selenite and tellurite compounds have garnered a lot of attention in both fundamental and applied chemistry. Se4+ and Te4+ cations possess lone pair electrons, which change the coordination environments and performance of these compounds. Here, three new transition metal selenite and tellurite compounds, MSe2O6 (M = Zr, Hf) and HfTe3O8, have been obtained by conventional hydrothermal reactions. The crystallographic structures of the three compounds are discussed in detail; meanwhile, thermal analysis, optical spectra, birefringence and theoretical calculations are also reported. Isostructural ZrSe2O6 and HfSe2O6 exhibit partially distorted octahedral and tetrahedral configurations. Moreover, ZrSe2O6 and HfSe2O6 have birefringence (Δn = 0.1052, 0.096) and short UV cut-off edges (212, 208 nm), and compared with ZrSe2O6, the thermal stability of HfSe2O6 is slightly larger. ZrSe2O6 and HfSe2O6 are adequate candidates as birefringent crystals in the UV region. Remarkably, HfTe3O8 not only has high thermal stability, but also provides a short UV cut-off edge (234 nm). It can meet the multiple requirements of the developing photoelectric system for UV window materials and has broad application prospects. Furthermore, the intrinsic relationship between the physical properties of the three crystals and their unique electronic structures is revealed. [ABSTRACT FROM AUTHOR]

Selenite and tellurite compounds have garnered a lot of attention in both fundamental and applied chemistry. Se4+ and Te4+ cations possess lone pair electrons, which change the coordination environments and performance of these compounds. Here, three new transition metal selenite and tellurite compounds, MSe2O6 (M = Zr, Hf) and HfTe3O8, have been obtained by conventional hydrothermal reactions. The crystallographic structures of the three compounds are discussed in detail; meanwhile, thermal analysis, optical spectra, birefringence and theoretical calculations are also reported. Isostructural ZrSe2O6 and HfSe2O6 exhibit partially distorted octahedral and tetrahedral configurations. Moreover, ZrSe2O6 and HfSe2O6 have birefringence (Δn = 0.1052, 0.096) and short UV cut-off edges (212, 208 nm), and compared with ZrSe2O6, the thermal stability of HfSe2O6 is slightly larger. ZrSe2O6 and HfSe2O6 are adequate candidates as birefringent crystals in the UV region. Remarkably, HfTe3O8 not only has high thermal stability, but also provides a short UV cut-off edge (234 nm). It can meet the multiple requirements of the developing photoelectric system for UV window materials and has broad application prospects. Furthermore, the intrinsic relationship between the physical properties of the three crystals and their unique electronic structures is revealed. [ABSTRACT FROM AUTHOR]

Environment‐friendly lead‐free potassium‐sodium niobate (KNN) has become one of the most extensively investigated ferroelectrics in the past decade, while high transparency KNN single crystal has never been realized yet. Here, a transparent KNN single crystal is successfully grown by the top seeded solution growth method. The KNN crystal possesses a very wide transmittance range of 0.37–8 µm, completely covering the important mid‐infrared atmospheric transparent window (3–5 µm). Noticeably, the KNN crystal exhibits the largest second‐harmonic generation efficiency (7.6× that of potassium‐titanyl phosphate (KTP)) with type‐I phase matchability under the fundamental wavelength of 1064 nm among all of the studied mid‐infrared oxide nonlinear optical crystals reported so far. This work demonstrates a novel mid‐infrared nonlinear optical oxide crystal with a giant second‐harmonic generation and wide transparency range, providing a new idea for the exploration of nonlinear oxide crystals. [ABSTRACT FROM AUTHOR]