Perovskite-Type Ca1−xSrxNbO3(0≤x≤1) Phases: a synthesis, structure, and electron microscopy study
1998 (English)In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 141, 514-521 p.Article in journal (Refereed) Published
Reduced niobates Ca1−xSrxNbO3(0≤x≤1) with perovskite-type structures have been synthesized at 1500°C in niobium ampoules sealed under argon gas. The prepared compounds were characterized by X-ray powder diffraction, electron diffraction, high-resolution electron microscopy, and energy-dispersive X-ray analysis. The structure of CaNbO3(GdFeO3type) was refined using X-ray powder diffraction data. Electron diffraction studies showed that complex superstructures of the perovskite-type structure occur forx>0 in Ca1−xSrxNbO3: (i) forx=0.2 and 0.3 reflections corresponding to a supercell witha≈2×√2×aper,b≈4×aper, andc≈2×√2×aper(per=ideal perovskite) were observed, (ii) forx=0.5, 0.6, and 0.7 a cubic supercell was found witha=4×aper, whereas (iii) forx=0.8 and 0.9 the supercell is probably orthorhombic witha≈c≈√2×aperandb≈2×aper. Forx=1.0 a new orthorhombic modification of SrNbO3witha≈c≈√2×aperandb≈2×aperwas found. Resistivity measurements showed CaNbO3to have a nonmetallic type of conductivity, whereas the Sr-containing samples were metallic.
Place, publisher, year, edition, pages
1998. Vol. 141, 514-521 p.
Research subject Inorganic Chemistry
IdentifiersURN: urn:nbn:se:su:diva-43885DOI: 10.1006/jssc.1998.8007OAI: oai:DiVA.org:su-43885DiVA: diva2:371569