Solid State Synthsis And Characterizations Of Muti-Compound Metal Chalcogenides

Metal chalcogenides with diversified structures and unusual properties can be achieved at intermediate temperature using the molten salt (alkali-metal polychalcogenide flux) method. Chalcogenides could offer good application prospects in the fields of superconductance, non-linear optics, high-energy battery and catalytic materials ect.Alkalimetal-containing multi-component metal chalcogenides, in general, in thermodynamically metastable state, and Q-Q bonds and M-M bonds, which lead to low dimensional structures, are often found, Moreover the compounds often have semiconducting behaviors in character.Only very few of the quaternary metal selenides KxMyM(y(Sez (M(=Zn,Cd,Hg) have been reported except K2Hg3Sn2Se, K2Hg3Ge2Se8, K6ZnSn5Se17 ect. In this dissertation, we mainly synthesized compounds which belong to KxMyM(y(Sez (M(=Zn,Cd,Hg) by molten salt method.Electron probe microanalyser was used for the qualitative and quantitive elemental analysis of the crystals selected. The results showed that we had synthesized thirteen novel quaternary metal selenides and ten ternary metal selenides by reactive flux method: K2CdIn2Se5,KHgSbSe3,KZnSbSe3,K4HgBiSe9,KHg4InSe6,K3CdSn3Se8,K2CdSnSe3,K2CdSnSe4,K2CdSn2Se5,K2CdSn3Se7,KPb3Sb3Se8,KCdInSe3,K2SnIn2Se6;K2Sn2Se4,K3Zr2Se9,KGeSe2,K9HgSe10,KGe2Se5,K3GeSe7,KNb2S7,K2NbSe9,K3In3Te,KBi9Se14.The structures of K2CdSnSe4 and K2Sn2Se4 have been determined by single-crystal Rigaku R-AXIS RAPID X-ray diffraction . Both of the two compounds are one-dimensional structure and crystallize in the tetragonal space group. Their space group is I-42m and I4cm.The compounds KHg4InSe6 and KZnSbSe3 were found to be lamellar by SEM and they were further identified to be new by powder X-ray diffraction experiment.The light absorbability of K2CdSnSe4, K2Sn2Se4 , KHg4InSe6 and KZnSbSe3 were also investigated using diffuse reflective spectra technique. The experiment results revealed that they are all semi-conductors and have strong light absorbability in a large range, which indicated that they are possible materials utilizing solar radiation. At last we discussed the syntheses method and influence factors on the synthesis of KxSnyCdy(Sez, including molar ratio of reactants, reaction temperature, molten salt, and so on.In this dissertation, many new members of KxMyM(y(Sez (M(=Zn,Cd,Hg) family have been obtained by molten salt method. The relation of structure and properties of the new members of KxSnyCdy(Sez family we have synthesized can be studied by further tests of crystal structure and properties.