New ternary alkalioxometallates of the first-row transition-metal elements through the azide nitrate route [Elektronische Ressource] / vorgelegt von Naveed Zafar Ali

Ali

Informations

• Publié par: universitat_stuttgart
• Publié le: 01 janvier 2011
• Nombre de lectures: 44
• Langue: English
• Poids de l'ouvrage: 18 Mo

Extrait

Max-Planck-Institute für Festkörperforschung

Stuttgart







New ternary alkalioxometallates of the first-row
transition-metal elements through the
Azide Nitrate Route

Naveed Zafar Ali















Dissertation an der Universität Stuttgart

Stuttgart, 2011




New ternary alkalioxometallates of the first-row transition-
metal elements through the Azide Nitrate Route



Von der Fakultät Chemie der Universität Stuttgart
zur Erlangung der Würde eines
Doktors der Naturwissenschaften (Dr. rer. nat.)
genehmigte Abhandlung



Vorgelegt von
Naveed Zafar Ali
aus Islamabad, Pakistan



Hauptberichter: Prof. Dr. Dr. h. c. mult. Martin Jansen
Mitberichter: Prof. Dr. Robert E. Dinnebier
Mitprüfer und Prüfungsvorsitzender: Prof. Dr. Thomas Schleid


Tag der Einreichung der Arbeit: 26.01.2011
Tag der mündlichen Prüfung: 02.03.2011



Max-Planck-Institut für Festkörperforschung, Stuttgart
2011










































































































Dedicated to: My Adorable Family.
Table of contents
Contents
1: Introduction…………………………………….……………………………… 1

2: Methods and instrumentation………………………………………………… 14
2.1 Working Methodology……………………………………………………… 14
2.1.1 Working under inert atmosphere……………..………………… 14
2.1.1.1 Vacuum and inert gas glass apparatus.......................... 14
2.1.1.2 Glove box..................................................................... 16
2.1.1.3 Schlenk technique........................................................ 17
2.1.2 Investigation under high pressure……………………………… 18
2.1.3 Azide-Nitrate/Nitrite Route…………………………………….. 20
2.1.4 Crystal growth………………………………………………….. 22
2.1.5 High – temperature laboratory furnaces………….…………... 23
2.2 Analytical Techniques………………………………………….…………. 24
2.2.1 X-ray diffraction methods………………………….………… 24
2.2.2 Powder X-ray diffraction………………………….…………. 24
2.2.3 Precession technique………………………………………….... 30
2.2.4 Single crystal diffraction……………………………………….. 31
2.2.5 Raman spectroscopy…………………………………………… 33
2.2.6 Energy dispersive X-ray spectroscopy (EDX+SEM) …………. 33
2.2.7 Thermal analysis…………………………………….................. 34
2.2.8 Temperature dependence of the specific heat (Cp) ……............. 36
2.2.9 Conductivity measurements…………………………................. 36
2.2.10 Magnetic measurements…………………………..................... 37
2.2.11 Mössbauer spectroscopy………………………........................ 40
2.2.12 Synchrotron radiation………………………............................. 43
2.2.13 Neutron diffraction………………………................................. 44
2.2.14 MAPLE calculations…………………….................................. 46
2.2.15 Bilbao crystallographic server……………………................... 47
2.3 References……………………....................................................................... 47
i Table of contents
3: Synthesis of (active) starting materials………………...................................... 50
3.1 Synthesis of alkali azides (AN ) ……………………..................................... 50 3
3.1.1 Lithium, potassium, rubidium and cesium azides….................... 50
3.1.2 Drying Assembly......................................................................... 54
3.2 Synthesis of (active) transition metal binary oxides....................................... 55
3.2.1 Iron(III)-oxide, Fe O ................................................................... 55 2 3
3.2.2 Cobalt(II-III)-oxide, Co O .......................................................... 57 3 4
3.2.3 Copper (II)-oxide, CuO................................................................ 58
3.2.4 Chromium (III)-oxide, Cr O ....................................................... 59 2 3
3.3 References....................................... ............................................................... 60

4: The AFeO (A = K, Rb and Cs) family 2
Three-dimensional magnetic iron oxides……………….................................... 61
4.1 Introduction…................................................................................................. 62
4.2 Experimental................................................................................................... 67
4.2.1 Synthesis...................................................................................... 67
4.2.2 X-ray single crystal diffraction.................................................... 68
4.2.3 High-resolution synchrotron powder diffraction......................... 73
4.2.4 Neutron diffraction experiments................................................. 73
4.2.5 Thermal analysis and magnetic susceptibility measurement…... 75
4.2.6 Mössbauer Spectroscopy on RbFeO and CsFeO ...................... 75 2 2
4.3 Results and discussion..................................................................................... 76
4.3.1 Single crystal X-ray diffraction.................................................... 76
4.3.2 Thermal analysis and magnetic susceptibility characterization……… 87
4.3.3 High-resolution synchrotron powder diffraction………………. 90
4.3.4 Neutron scattering experiments................................................... 102
4.4 Discussion and Conclusions............................................................................ 116
4.5 Mössbauer Spectroscopy on RbFeO and CsFeO .......................................... 122 2 2
4.6 Parametric Rietveld refinement....................................................................... 129
4.7 References....................................................................................................... 132

ii Table of contents
5: New two-dimensional layered magnetic oxides................................................ 136
5-A: Synthesis, crystal structure and magnetic properties of CsCoO , 2
a new two dimensional layered structure............................................................ 137
5.1 Introduction..................................................................................................... 137
5.2 Experimental Details....................................................................................... 139
5.3 Results and discussion..................................................................................... 144
5.3.1 Single crystal X-ray diffraction.................................................... 144
5.3.2 Structural phase transitions in CsCoO ........................................ 150 2
5.3.3 The result of a temperature-dependent resistivity........................ 154
5.3.4 Thermal analysis and magnetic characterization......................... 156
5.4 Conclusion....................................................................................................... 159
5-B: Synthesis, crystal structure and magnetic properties of β-KCrO ........................ 161 2
5.5 Introduction..................................................................................................... 161
5.6 Experimental................................................................................................... 162
5.7 Results and discussion..................................................................................... 168
5.7.1 Description of crystal structure.................................................... 168
5.7.2 MAPLE calculations.................................................................... 170
5.8 Structural phase transitions............................................................................. 171
5.9 A comparison of α-KCrO to β-KCrO ........................................................... 174 2 2
5.10 Magnetic properties....................................................................................... 175
5.11 The specific heat for KCrO .......................................................................... 178 2
5.12 Conclusion..................................................................................................... 179
5.13 References..................................................................................................... 180


6: One-Dimensional Alkali-oxocuprates................................................................ 186
6.1. Synthesis, structure and magnetic properties of the new Wigner
crystallized chain cuprate Na C