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Graduate School of Ajou University Department of Energy Systems 3. Theses(Master)

새로운 2 차원 사성분계 황화물의 합성 및 구조 연구

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dc.contributor.advisor윤호섭-
dc.contributor.author배상현-
dc.date.accessioned2022-11-29T03:01:16Z-
dc.date.available2022-11-29T03:01:16Z-
dc.date.issued2020-02-
dc.identifier.other29859-
dc.identifier.urihttps://dspace.ajou.ac.kr/handle/2018.oak/20947-
dc.description학위논문(석사)--아주대학교 일반대학원 :에너지시스템학과,2020. 2-
dc.description.tableofcontentsCHAPTER Ι. Synthesis and Structural Studies of a New Two-dimensional Quaternary Sulfide, Cs2HfPd3S6 1 Abstract 2 Introduction 3 Experimental 4 Synthesis 4 X-ray Crystallography 4 Result and discussion 6 Figure 1. (a) Square planar PdS4, (b) trigonal prism HfS6, and (c) basic repeating units, Hf2Pd2S12 7 Figure 2. Linking mode of the basic units 8 Figure 3. The infinite two-dimensional layer 2[HfPd3S62-] 9 Figure 4. Perspective view of the CsHfPd3S6 10 Figure 5. The structure of CsHfPd3S6 11 Table 1. Crystallographic details for Cs2HfPd3S6 and related compounds 12 Table 2.Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (2) for Cs2HfPd3S6 13 Table 3. Anisotropic displacement parameters (2) for Cs2HfPd3S6 14 Table 4. Selected bond distances () and Angles () for Cs2HfPd3S6 15 CHAPTER ΙI. Synthesis and Structural Studies of a New Mixed-valent Two-dimensional Quaternary Sulfide, K2Ta6Pd9S24 23 Abstract 24 Introduction 25 Experimental 26 Synthesis 26 X-ray Crystallography 26 Result and discussion 28 Figure 1. (a) Square planar PdS4, (b) trigonal prism TaS6, and (c) basic repeating units, Ta2Pd2S12 29 Figure 2. Linking mode of the basic units 30 Figure 3. The infinite two-dimensional layer 2[Ta6Pd9S242-] 31 Figure 4. The infinite two-dimensional layer 2[Ta6Pd9S242-] with alkali metal 32 Figure 5. The structure of K2Ta6Pd9S24 33 Table 1. Crystallographic details for K2Ta6Pd9S24 33 Table 2. Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (2) for K2Ta6Pd9S24 34 Table 3. Anisotropic displacement parameters (2) for K2Ta6Pd9S24 35 Table 4. Selected bond distances () and Angles () for K2Ta6Pd9S24 36-
dc.language.isoeng-
dc.publisherThe Graduate School, Ajou University-
dc.rights아주대학교 논문은 저작권에 의해 보호받습니다.-
dc.title새로운 2 차원 사성분계 황화물의 합성 및 구조 연구-
dc.title.alternativeBae Sanghyun-
dc.typeThesis-
dc.contributor.affiliation아주대학교 일반대학원-
dc.contributor.alternativeNameBae Sanghyun-
dc.contributor.department일반대학원 에너지시스템학과-
dc.date.awarded2020. 2-
dc.description.degreeMaster-
dc.identifier.localId1138698-
dc.identifier.uciI804:41038-000000029859-
dc.identifier.urlhttp://dcoll.ajou.ac.kr:9080/dcollection/common/orgView/000000029859-
dc.description.alternativeAbstractChalcogens (S, Se, and Te) are less electronegative and more polarizable compared with oxygen and they show greater covalencies and inter-chalcogen interactions. As a result, chalcogenides prefer low-dimensional structures and usually they have anisotropic structures and properties. Research in the alkali metal transition metal chalcogenides have been a very active area for two decades due to their unusual structural features and the novel physical properties. However, no quaternary alkali metals/early transition metals/ palladium chalcogenide has ever been reported yet. In our laboratory, we have prepared a number of multinary chalcogenides with the use of alkali metal halide as reactive fluxes and we were able to prepare new phases in this family. The new quaternary palladium sulfides, K2Ta6Pd9S24 and Cs2HfPd3S6 have been prepared from elemental powders through alkali metal halide flux methods and they are structurally characterized by single crystal X-ray diffraction techniques. They adopt two-dimensional layered structures. In these layers, the early transition metals of the groups 4 or 5 (Hf, Ta) are surrounded by six S atoms in a trigonal prismatic fashion and the Pd atoms are coordinated to four square planar S atoms. The structural diversity of these compounds come from the different connecting mode of these building blocks. In chapter I, synthesis and structure of the quaternary palladium sulfides, Cs2HfPd3S6 is discussed along with the related phases, Cs2ZrPd3S6 and CsTaPd3S6. For Cs2HfPd3S6, two HfS6 units are bridged by two Pd atoms by sharing edges to form the basic repeating units, Hf2Pd2S12. These units are linked together to complete the infinite anionic two-dimensional layer, 2¦∞[HfPd3S62-]. These layers stack on top of each other and the Cs+ ions reside between the layers to satisfy the charge neutrality to complete the structure. Replacement of tetravalent Hf4+ or Zr4+ with pentavalent Ta5+ has led to a new phase, CsTaPd3S6. In this compound, the layer, 2¦∞[TaPd3S6-] remains intact but the content of alkali metals should be reduced half to satisfy the charge neutrality. There is no strong S-S bonding interaction in these phases and assigning oxidation states of each element is clear. The charge valence of the compounds can be described as [Cs+]2[M4+][Pd2+]3[S2-]6 (Hf, Zr) and [Cs+][Ta5+][Pd2+]3[S2-]6. In chapter II, for K2Ta6Pd9S24, two trigonal prismatic TaS6 units are bridged by two Pd atoms by sharing edges to form the basic repeating units, Ta2Pd2S12. They are connected via Pd atoms to form a two-dimensional layer, 2¦∞[Ta6Pd9S242-]. These layers are separated by K+ ions through electrostatic coulombic interactions. Assigning the oxidation state of Ta in this compound is not straightforward. Especially, the oxidation state of Ta cannot be fixed as an integer. Consequently, we propose a randomly disordered mixed-valence model composed of 2/3 Ta5+ and 1/3 Ta4+ ions and the charge valence of the compound can be described as [K+]2[Ta4+]2[Ta5+]4[Pd2+]9[S2-]24.-
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