{"id":{"repo_id":"birmingham","oai_identifier":"oai:etheses.bham.ac.uk:484"},"canonical_url":"https://search.dev.ndltd.org/etd/birmingham/oai:etheses.bham.ac.uk:484","repository":{"repo_id":"birmingham","name":"University of Birmingham","base_url":"https://etheses.bham.ac.uk/cgi/oai2"},"display":{"title":"Anion manipulation in perovskite-related materials","abstract":"Sr\\(_2\\)Co\\(_2\\)O\\(_5\\) with the perovskite-related brownmillerite structure has been synthesised via quenching, with the orthorhombic unit cell parameters \\(a\\) = 5.4639(3) Å, \\(b\\) = 15.6486(8) Å and \\(c\\) = 5.5667(3) Å based on refinement of NPD data collected at 4K. Electron microscopy revealed L R L R intralayer ordering of chain orientations which requires a doubling of the unit cell along the \\(c\\) parameter, consistent with the assignment of the space group \\(Pcmb\\). However, on the length scale pertinent to NPD, no long-range order is observed and the disordered space group \\(Imma\\) appears more appropriate. Low-temperature fluorination of this material and the related brownmillerite phases Sr\\(_2\\)CoFeO\\(_5\\) and Sr\\(_2\\)Fe\\(_2\\)O\\(_5\\) has been found to give different products depending on the starting material. Sr\\(_2\\)Co\\(_2\\)O\\(_5\\) and Sr\\(_2\\)CoFeO\\(_5\\) are amenable to fluorine insertion reactions with corresponding oxidation of transition metal cations, forming cubic perovskite phases of the nominal compositions SrCoO\\(_{2.5}\\)F\\(_{0.5}\\) (\\(a\\) = 3.8574(3) Å) and SrCo\\(_{0.5}\\)Fe\\(_{0.5}\\)O\\(_{2.5}\\)F\\(_{0.5}\\) (\\(a\\) = 3.872(2) Å). Fluorination of Sr\\(_2\\)Fe\\(_2\\)O\\(_5\\), however, results in a 1:1 mixture of two phases that were assigned to SrFeO\\(_2\\)F (\\(a\\) = 3.9481(3) Å) and SrFeO\\(_{3-δ}\\) (\\(a\\) = 3.8775(3) Å). Fluorine insertion into the oxygen defect superstructure manganite Sr\\(_2\\)MnO\\(_{3.5+x}\\) has been shown by TEM to result in two levels of fluorination. In the higher fluorine content sections, the fluorine anions displace oxygen anions from their apical positions into the equatorial vacancies, thus destroying the superstructure and giving a K\\(_2\\)NiF\\(_4\\) type structure (\\(a\\) = 3.8210(1) Å and \\(c\\) = 12.686(1) Å). Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\) with tetragonal symmetry (\\(P4/nmm\\) \\(a\\) = 3.8554(4) Å and \\(c\\) = 13.088(4) Å based on neutron powder diffraction) and a structure related to LaSrMnO\\(_4\\)F has been synthesised via low-temperature fluorination of the ternary nitride Ce\\(_2\\)MnN\\(_3\\). Two F\\(^-\\) anions are inserted but no F\\(^-\\)/N3\\(^-\\) substitution takes place, instead a structural rearrangement whereby one F\\(^-\\) expands the manganese coordination from four to six occurs and the second F\\(^-\\) inserts in alternate layers of interstitial sites, in a staged fashion. The effective magnetic moment in Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\), μ\\(_{eff}\\) = 5.38 μ\\(_B\\), is consistent with an intermediate value between that of Mn\\(^{3+}\\) (4.9 μ\\(_B\\)) and Mn\\(^{2+}\\) (5.9 μ\\(_B\\)) supporting the proposed stoichiometry, Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\).","abstract_html":"Sr<span class=\"etd-inline-math\"><sub>2</sub></span>Co<span class=\"etd-inline-math\"><sub>2</sub></span>O<span class=\"etd-inline-math\"><sub>5</sub></span> with the perovskite-related brownmillerite structure has been synthesised via quenching, with the orthorhombic unit cell parameters \\(a\\) = 5.4639(3) Å, \\(b\\) = 15.6486(8) Å and \\(c\\) = 5.5667(3) Å based on refinement of NPD data collected at 4K. Electron microscopy revealed L R L R intralayer ordering of chain orientations which requires a doubling of the unit cell along the \\(c\\) parameter, consistent with the assignment of the space group \\(Pcmb\\). However, on the length scale pertinent to NPD, no long-range order is observed and the disordered space group \\(Imma\\) appears more appropriate. Low-temperature fluorination of this material and the related brownmillerite phases Sr<span class=\"etd-inline-math\"><sub>2</sub></span>CoFeO<span class=\"etd-inline-math\"><sub>5</sub></span> and Sr<span class=\"etd-inline-math\"><sub>2</sub></span>Fe<span class=\"etd-inline-math\"><sub>2</sub></span>O<span class=\"etd-inline-math\"><sub>5</sub></span> has been found to give different products depending on the starting material. Sr<span class=\"etd-inline-math\"><sub>2</sub></span>Co<span class=\"etd-inline-math\"><sub>2</sub></span>O<span class=\"etd-inline-math\"><sub>5</sub></span> and Sr<span class=\"etd-inline-math\"><sub>2</sub></span>CoFeO<span class=\"etd-inline-math\"><sub>5</sub></span> are amenable to fluorine insertion reactions with corresponding oxidation of transition metal cations, forming cubic perovskite phases of the nominal compositions SrCoO<span class=\"etd-inline-math\"><sub>2.5</sub></span>F<span class=\"etd-inline-math\"><sub>0.5</sub></span> (\\(a\\) = 3.8574(3) Å) and SrCo<span class=\"etd-inline-math\"><sub>0.5</sub></span>Fe<span class=\"etd-inline-math\"><sub>0.5</sub></span>O<span class=\"etd-inline-math\"><sub>2.5</sub></span>F<span class=\"etd-inline-math\"><sub>0.5</sub></span> (\\(a\\) = 3.872(2) Å). Fluorination of Sr<span class=\"etd-inline-math\"><sub>2</sub></span>Fe<span class=\"etd-inline-math\"><sub>2</sub></span>O<span class=\"etd-inline-math\"><sub>5</sub></span>, however, results in a 1:1 mixture of two phases that were assigned to SrFeO<span class=\"etd-inline-math\"><sub>2</sub></span>F (\\(a\\) = 3.9481(3) Å) and SrFeO<span class=\"etd-inline-math\"><sub>3-δ</sub></span> (\\(a\\) = 3.8775(3) Å). Fluorine insertion into the oxygen defect superstructure manganite Sr<span class=\"etd-inline-math\"><sub>2</sub></span>MnO<span class=\"etd-inline-math\"><sub>3.5+x</sub></span> has been shown by TEM to result in two levels of fluorination. In the higher fluorine content sections, the fluorine anions displace oxygen anions from their apical positions into the equatorial vacancies, thus destroying the superstructure and giving a K<span class=\"etd-inline-math\"><sub>2</sub></span>NiF<span class=\"etd-inline-math\"><sub>4</sub></span> type structure (\\(a\\) = 3.8210(1) Å and \\(c\\) = 12.686(1) Å). Ce<span class=\"etd-inline-math\"><sub>2</sub></span>MnN<span class=\"etd-inline-math\"><sub>3</sub></span>F<span class=\"etd-inline-math\"><sub>2-δ</sub></span> with tetragonal symmetry (\\(P4/nmm\\) \\(a\\) = 3.8554(4) Å and \\(c\\) = 13.088(4) Å based on neutron powder diffraction) and a structure related to LaSrMnO<span class=\"etd-inline-math\"><sub>4</sub></span>F has been synthesised via low-temperature fluorination of the ternary nitride Ce<span class=\"etd-inline-math\"><sub>2</sub></span>MnN<span class=\"etd-inline-math\"><sub>3</sub></span>. Two F<span class=\"etd-inline-math\"><sup>-</sup></span> anions are inserted but no F<span class=\"etd-inline-math\"><sup>-</sup></span>/N3<span class=\"etd-inline-math\"><sup>-</sup></span> substitution takes place, instead a structural rearrangement whereby one F<span class=\"etd-inline-math\"><sup>-</sup></span> expands the manganese coordination from four to six occurs and the second F<span class=\"etd-inline-math\"><sup>-</sup></span> inserts in alternate layers of interstitial sites, in a staged fashion. The effective magnetic moment in Ce<span class=\"etd-inline-math\"><sub>2</sub></span>MnN<span class=\"etd-inline-math\"><sub>3</sub></span>F<span class=\"etd-inline-math\"><sub>2-δ</sub></span>, μ<span class=\"etd-inline-math\"><sub>eff</sub></span> = 5.38 μ<span class=\"etd-inline-math\"><sub>B</sub></span>, is consistent with an intermediate value between that of Mn<span class=\"etd-inline-math\"><sup>3+</sup></span> (4.9 μ<span class=\"etd-inline-math\"><sub>B</sub></span>) and Mn<span class=\"etd-inline-math\"><sup>2+</sup></span> (5.9 μ<span class=\"etd-inline-math\"><sub>B</sub></span>) supporting the proposed stoichiometry, Ce<span class=\"etd-inline-math\"><sub>2</sub></span>MnN<span class=\"etd-inline-math\"><sub>3</sub></span>F<span class=\"etd-inline-math\"><sub>2-δ</sub></span>.","abstract_has_math":true,"creators":["Sullivan, Eirin Courtney"],"institution":"University of Birmingham","degree_name":"d_ph","degree_level":"d_ph","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2009,"date_issued":"2009-12","date_published":"2009-12","updated_at":"2026-07-24T01:10:58Z","subjects":["QD Chemistry"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.sponsor","label":"Sponsor","values":["na"]},{"key":"dc:creator","label":"Author","values":["Sullivan, Eirin Courtney"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2009-12"]},{"key":"dc:date.issued","label":"Date","values":["2009-12"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["College of Engineering & Physical Sciences","School of Chemistry"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Birmingham"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["http://etheses.bham.ac.uk//id/eprint/484/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["d_ph"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["d_ph"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["QD Chemistry"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://etheses.bham.ac.uk//id/eprint/484/1/Sullivan09PhD_A1b.pdf","http://etheses.bham.ac.uk//id/eprint/484/2/Decl_IS_Sullivan09PhD.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Sr\\(_2\\)Co\\(_2\\)O\\(_5\\) with the perovskite-related brownmillerite structure has been synthesised via quenching, with the orthorhombic unit cell parameters \\(a\\) = 5.4639(3) Å, \\(b\\) = 15.6486(8) Å and \\(c\\) = 5.5667(3) Å based on refinement of NPD data collected at 4K. Electron microscopy revealed L R L R intralayer ordering of chain orientations which requires a doubling of the unit cell along the \\(c\\) parameter, consistent with the assignment of the space group \\(Pcmb\\). However, on the length scale pertinent to NPD, no long-range order is observed and the disordered space group \\(Imma\\) appears more appropriate. Low-temperature fluorination of this material and the related brownmillerite phases Sr\\(_2\\)CoFeO\\(_5\\) and Sr\\(_2\\)Fe\\(_2\\)O\\(_5\\) has been found to give different products depending on the starting material. Sr\\(_2\\)Co\\(_2\\)O\\(_5\\) and Sr\\(_2\\)CoFeO\\(_5\\) are amenable to fluorine insertion reactions with corresponding oxidation of transition metal cations, forming cubic perovskite phases of the nominal compositions SrCoO\\(_{2.5}\\)F\\(_{0.5}\\) (\\(a\\) = 3.8574(3) Å) and SrCo\\(_{0.5}\\)Fe\\(_{0.5}\\)O\\(_{2.5}\\)F\\(_{0.5}\\) (\\(a\\) = 3.872(2) Å). Fluorination of Sr\\(_2\\)Fe\\(_2\\)O\\(_5\\), however, results in a 1:1 mixture of two phases that were assigned to SrFeO\\(_2\\)F (\\(a\\) = 3.9481(3) Å) and SrFeO\\(_{3-δ}\\) (\\(a\\) = 3.8775(3) Å). Fluorine insertion into the oxygen defect superstructure manganite Sr\\(_2\\)MnO\\(_{3.5+x}\\) has been shown by TEM to result in two levels of fluorination. In the higher fluorine content sections, the fluorine anions displace oxygen anions from their apical positions into the equatorial vacancies, thus destroying the superstructure and giving a K\\(_2\\)NiF\\(_4\\) type structure (\\(a\\) = 3.8210(1) Å and \\(c\\) = 12.686(1) Å). Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\) with tetragonal symmetry (\\(P4/nmm\\) \\(a\\) = 3.8554(4) Å and \\(c\\) = 13.088(4) Å based on neutron powder diffraction) and a structure related to LaSrMnO\\(_4\\)F has been synthesised via low-temperature fluorination of the ternary nitride Ce\\(_2\\)MnN\\(_3\\). Two F\\(^-\\) anions are inserted but no F\\(^-\\)/N3\\(^-\\) substitution takes place, instead a structural rearrangement whereby one F\\(^-\\) expands the manganese coordination from four to six occurs and the second F\\(^-\\) inserts in alternate layers of interstitial sites, in a staged fashion. The effective magnetic moment in Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\), μ\\(_{eff}\\) = 5.38 μ\\(_B\\), is consistent with an intermediate value between that of Mn\\(^{3+}\\) (4.9 μ\\(_B\\)) and Mn\\(^{2+}\\) (5.9 μ\\(_B\\)) supporting the proposed stoichiometry, Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\)."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Anion manipulation in perovskite-related materials"]}]}],"canonical_facts":{"dc:contributor.sponsor":["na"],"dc:creator":["Sullivan, Eirin Courtney"],"dc:date":["2009-12"],"dc:date.issued":["2009-12"],"dc:description.abstract":["Sr\\(_2\\)Co\\(_2\\)O\\(_5\\) with the perovskite-related brownmillerite structure has been synthesised via quenching, with the orthorhombic unit cell parameters \\(a\\) = 5.4639(3) Å, \\(b\\) = 15.6486(8) Å and \\(c\\) = 5.5667(3) Å based on refinement of NPD data collected at 4K. Electron microscopy revealed L R L R intralayer ordering of chain orientations which requires a doubling of the unit cell along the \\(c\\) parameter, consistent with the assignment of the space group \\(Pcmb\\). However, on the length scale pertinent to NPD, no long-range order is observed and the disordered space group \\(Imma\\) appears more appropriate. Low-temperature fluorination of this material and the related brownmillerite phases Sr\\(_2\\)CoFeO\\(_5\\) and Sr\\(_2\\)Fe\\(_2\\)O\\(_5\\) has been found to give different products depending on the starting material. Sr\\(_2\\)Co\\(_2\\)O\\(_5\\) and Sr\\(_2\\)CoFeO\\(_5\\) are amenable to fluorine insertion reactions with corresponding oxidation of transition metal cations, forming cubic perovskite phases of the nominal compositions SrCoO\\(_{2.5}\\)F\\(_{0.5}\\) (\\(a\\) = 3.8574(3) Å) and SrCo\\(_{0.5}\\)Fe\\(_{0.5}\\)O\\(_{2.5}\\)F\\(_{0.5}\\) (\\(a\\) = 3.872(2) Å). Fluorination of Sr\\(_2\\)Fe\\(_2\\)O\\(_5\\), however, results in a 1:1 mixture of two phases that were assigned to SrFeO\\(_2\\)F (\\(a\\) = 3.9481(3) Å) and SrFeO\\(_{3-δ}\\) (\\(a\\) = 3.8775(3) Å). Fluorine insertion into the oxygen defect superstructure manganite Sr\\(_2\\)MnO\\(_{3.5+x}\\) has been shown by TEM to result in two levels of fluorination. In the higher fluorine content sections, the fluorine anions displace oxygen anions from their apical positions into the equatorial vacancies, thus destroying the superstructure and giving a K\\(_2\\)NiF\\(_4\\) type structure (\\(a\\) = 3.8210(1) Å and \\(c\\) = 12.686(1) Å). Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\) with tetragonal symmetry (\\(P4/nmm\\) \\(a\\) = 3.8554(4) Å and \\(c\\) = 13.088(4) Å based on neutron powder diffraction) and a structure related to LaSrMnO\\(_4\\)F has been synthesised via low-temperature fluorination of the ternary nitride Ce\\(_2\\)MnN\\(_3\\). Two F\\(^-\\) anions are inserted but no F\\(^-\\)/N3\\(^-\\) substitution takes place, instead a structural rearrangement whereby one F\\(^-\\) expands the manganese coordination from four to six occurs and the second F\\(^-\\) inserts in alternate layers of interstitial sites, in a staged fashion. The effective magnetic moment in Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\), μ\\(_{eff}\\) = 5.38 μ\\(_B\\), is consistent with an intermediate value between that of Mn\\(^{3+}\\) (4.9 μ\\(_B\\)) and Mn\\(^{2+}\\) (5.9 μ\\(_B\\)) supporting the proposed stoichiometry, Ce\\(_2\\)MnN\\(_3\\)F\\(_{2-δ}\\)."],"dc:format":["application/pdf"],"dc:identifier.uri":["http://etheses.bham.ac.uk//id/eprint/484/1/Sullivan09PhD_A1b.pdf","http://etheses.bham.ac.uk//id/eprint/484/2/Decl_IS_Sullivan09PhD.pdf"],"dc:publisher.department":["College of Engineering & Physical Sciences","School of Chemistry"],"dc:publisher.institution":["University of Birmingham"],"dc:relation.isreferencedby":["http://etheses.bham.ac.uk//id/eprint/484/"],"dc:subject":["QD Chemistry"],"dc:title":["Anion manipulation in perovskite-related materials"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["d_ph"],"dc:type.qualificationname":["d_ph"]},"updated_at":"2026-07-24T01:10:58Z"}