heather kukkee hbsc thesis abstract

perovskite-type compounds in the series tausonite-lueshite, (srtio₃-nanbo₃), were synthesized by solid-state reaction and analyzed using x-ray powder diffractometry.  the structures of several intermediate compositions were determined using the rietveld refinement method.  in the compositional range 0≤ x ≤0.2, the series consists of an undistorted cubic structure in the space group pm3m, with cell dimensions ranging from a≈3.905-3.916....  at the composition of x=0.9, a combination of the orthorhombic spaces groups pbma and pbnm is believed to occur (a ≈ 5.558, b ≈ 15.625, c ≈ 5.519 ...).  in the compositional range 0.95≤ x ≤1.00, the structure is orthorhombic and belongs to the space group pbma.  in the series (srtio₃-nanbo₃), the degree of structural distortion increases with x as a result of na substituting into the a-site for sr, and nb substituting into the b-site for ti.