Syntheses, Structures And Properties Of Novel Multinary Metal Selenides

Multinary metal selenides have extensively been studied because of their rich structural chemistry and chemical or physical properties.In this dissertation, we synthesized ten novel multi-component metal selenides by reactive flux method at intermediate temperature, which are KSnSe5, K7SnSe5, K4InSe3, K3InSe3, K2InSe2, AgBiS3, K4Sn3Se8, KAgBiSe4, K4Cu4GeSe13, and K2AgIn3Se6.The structures of K2AgIn3Se6 and K4Sn3Se8 have been determined by single-crystal X-ray diffraction. K2AgIn3Se6 crystallized in monoclinic space group C2/c with cell parameters a = 11.6411(7) ?, b = 11.6348(8) ?, c = 21.4179(12) ?, V = 2874.0(9) ?3, Z = 8. The crystal structure of K2AgIn3Se6 is constructed by packing neutral [K2AgIn3Se6] layers parallel to (001) plane along the c-axis direction through intermolecular force. K4Sn3Se8 crystals crystallized in orthorhombic space group Ccca with cell parameters, a = 8.2115(6) ? , b= 27.790(2) ?, c = 8.1865(6) ?, V = 1868.2(2) ? 3, Z = 4. K4Sn3Se8 is a zero-dimensional structure consisting of [Sn3Se8]4- trimeric anions and K+ cations. At the same time, the new AgBiS3 crystal was tested by XRD method. UV-VIS-NIR reflective spectrum studies indicated that K2AgIn3Se6 is an insulator with an energy gape of 2.8eV, K4Sn3Se8 a semiconductor with an energy gape of 2.4eV and AgBiS3 also a conductor with an energy gape of 0.79eV.At last we discussed the influence factors on the results from the flux reactions, including molar ratio of reactants, reaction temperature, heating program, cooling rate, and so on.