Synthesis and characterization of reduced niobates CaLnNb2O7, Ln = Y, Nd with a pyrochlore structure
- 1. Moscow State Univ. (Russian Federation). Dept. of Chemistry
- 2. Stockholm Univ. (Sweden). Arrhenius Lab.
Description
The first known reduced niobates with a pyrochlore structure, CaLnNb2O7 Ln = Y, Nd, have been synthesized from Ca2Nb2O7, Ln2O3, and NbO2 in sealed Nb ampoules heated at 1,400 C for 6 h. Their studies show that these compounds have a small homogeneity region according to the formula Ca2-xLnxNb2O7, Ln = Nd with x = 0.9, 1.0; and Ln = Y with x = 1.0, 1.1. The prepared compounds were characterized by EDX (energy dispersive X-ray) analysis, X-ray and electron diffraction, and thermogravimetric analysis. The crystal structures of CaNdNb2O7 and CaYNb2O7 were refined using X-ray and neutron powder diffraction data. CaNdNb2O7 and CaYNb2O7 have undistorted pyrochlore structures: space group Fd3m, a = 10.416(1) A and 10.3159(8) A, respectively. Resistivity measurements show that CaNdNb2O7 exhibits semiconducting behavior
Additional details
Publishing Information
- Journal Title
- Materials Research Bulletin
- Journal Volume
- 32
- Journal Issue
- 4
- Journal Page Range
- p. 421-430.
- ISSN
- 0025-5408
- CODEN
- MRBUAC
INIS
- Country of Publication
- United States
- Country of Input or Organization
- United States
- INIS RN
- 28058523
- Subject category
- S36: MATERIALS SCIENCE;
- Resource subtype / Literary indicator
- Numerical Data
- Descriptors DEI
- CALCIUM OXIDES; CHEMICAL PREPARATION; CRYSTAL STRUCTURE; ELECTRIC CONDUCTIVITY; EXPERIMENTAL DATA; NEODYMIUM OXIDES; NEUTRON DIFFRACTION; NIOBIUM OXIDES; STOICHIOMETRY; X-RAY DIFFRACTION; YTTRIUM OXIDES
- Descriptors DEC
- ALKALINE EARTH METAL COMPOUNDS; CALCIUM COMPOUNDS; CHALCOGENIDES; COHERENT SCATTERING; DATA; DIFFRACTION; ELECTRICAL PROPERTIES; INFORMATION; NEODYMIUM COMPOUNDS; NIOBIUM COMPOUNDS; NUMERICAL DATA; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; RARE EARTH COMPOUNDS; SCATTERING; SYNTHESIS; TRANSITION ELEMENT COMPOUNDS; YTTRIUM COMPOUNDS