The synthesis and characterisation of complex metal oxide materials
The synthesis and characterisation of complex metal oxide materials
A new palladate analogue, Ba11Pd11O20(CO3)2, of the complex copper oxide carbonate, Ba44Cu48O87.9(CO3)6, has been synthesised by reaction of PdO and BaCO3 at 810oC. The structure of this phase and that of the isostructural nickelate have been refined from high resolution powder neutron diffraction data. The structure consists of M18O24 cages and M6O12 rings (M = Pd, Ni), previously unknown for these metals, separated by barium ions and carbonate groups. A section of the structure separating two of M18O24 units exhibits a high degree of disorder and has been refined as containing either carbonate groups or isolated MO4 square planes. The presence and symmetry of the carbonate groups in these structures has been investigated by infrared and Raman spectroscopy.
Three solid solutions containing copper and palladium in square planar coordination have been synthesised and characterised. The 'BaCuxPd1-xO2' system adopts the barium palladium oxide carbonate structure, described above, over the entire range of x(0 ≤ x ≤ 1). CuxPd2-x O2 (0 ≤ x ≤ 11/2) has also been studied, crystallising with the PdO structure type, although the purely copper containing material, CuO, could not be synthesised with this structure. Sr2CuxPd1-xO3 (0 < x < 1) was found to be isostructural with the end members of the series. Attempts to introduce palladium into the double chains of copper oxygen square planes in YBa2Cu4O8+δ were unsuccessful.
Complete structural characterisation of Pb2Ba2Cu2MO8Cl (M = Nb, Ta) via the combined refinement of powder x-ray and neutron diffraction data, has been achieved, confirming the previous x-ray refinement. Structural analogues of this material have been synthesised giving the series of compounds, PbyBa4-yCu2MO8X (y = 2, 3; M = Nb, Ta, Sb; X = Cl, Br) of which seven new products have been isolated. Structural characterisation of these materials has been performed using the Rietveld refinement of powder x-ray diffraction data, indicating that all of these materials adopt the PB2Ba2Cu2TaO8Cl structure type where Pb2Cl layers separate triple layers formed from two CuO5 square pyramids sandwiching a distorted TaO6 octahedron.
University of Southampton
1997
Crooks, Richard James
(1997)
The synthesis and characterisation of complex metal oxide materials.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
A new palladate analogue, Ba11Pd11O20(CO3)2, of the complex copper oxide carbonate, Ba44Cu48O87.9(CO3)6, has been synthesised by reaction of PdO and BaCO3 at 810oC. The structure of this phase and that of the isostructural nickelate have been refined from high resolution powder neutron diffraction data. The structure consists of M18O24 cages and M6O12 rings (M = Pd, Ni), previously unknown for these metals, separated by barium ions and carbonate groups. A section of the structure separating two of M18O24 units exhibits a high degree of disorder and has been refined as containing either carbonate groups or isolated MO4 square planes. The presence and symmetry of the carbonate groups in these structures has been investigated by infrared and Raman spectroscopy.
Three solid solutions containing copper and palladium in square planar coordination have been synthesised and characterised. The 'BaCuxPd1-xO2' system adopts the barium palladium oxide carbonate structure, described above, over the entire range of x(0 ≤ x ≤ 1). CuxPd2-x O2 (0 ≤ x ≤ 11/2) has also been studied, crystallising with the PdO structure type, although the purely copper containing material, CuO, could not be synthesised with this structure. Sr2CuxPd1-xO3 (0 < x < 1) was found to be isostructural with the end members of the series. Attempts to introduce palladium into the double chains of copper oxygen square planes in YBa2Cu4O8+δ were unsuccessful.
Complete structural characterisation of Pb2Ba2Cu2MO8Cl (M = Nb, Ta) via the combined refinement of powder x-ray and neutron diffraction data, has been achieved, confirming the previous x-ray refinement. Structural analogues of this material have been synthesised giving the series of compounds, PbyBa4-yCu2MO8X (y = 2, 3; M = Nb, Ta, Sb; X = Cl, Br) of which seven new products have been isolated. Structural characterisation of these materials has been performed using the Rietveld refinement of powder x-ray diffraction data, indicating that all of these materials adopt the PB2Ba2Cu2TaO8Cl structure type where Pb2Cl layers separate triple layers formed from two CuO5 square pyramids sandwiching a distorted TaO6 octahedron.
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Published date: 1997
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Local EPrints ID: 463177
URI: http://eprints.soton.ac.uk/id/eprint/463177
PURE UUID: 3adf2e0c-9385-48bb-9900-c805d337db67
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Date deposited: 04 Jul 2022 20:47
Last modified: 04 Jul 2022 20:47
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Author:
Richard James Crooks
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