Abstract
The crystalline structure of new TlSr 2 PrCu 2 0 7−x was obtained at room temperature (300 K) and low temperature (100 K) from X-ray powder diffraction with CuKα radiation using Rietveld analysis. TlSr 2 PrCu 2 0 7−x has an isotypical structure with TlBa 2 CaCu 2 0 7 (1212). At 300 K, crystal data: Tl 0.864 Sr 2 PrCu 2 O 6.75 , M r =727.811, the tetragonal system, P4/mmm, a =3.85404(5) Å, c = 12.1046(2) Å, V=179.80 Å 3 , Z=1, D x =6.7218 g cm −3 , μ =1143.922 cm −1 (λ = 1.54051 Å), F(000)=317.0, the structure was refined with 28 parameters to R wp =5.29%, R p = 3.65% for 3551 step intensities and R b =7.40%, R f =639% for 155 peaks, “goodness of fit” 5=3.05. At 100 K, crystal data: Tl 0.858 Sr 2 PrCu 2 O 6.61 , M r =724.345, the tetragonal system, P4/mmm, a =3.84872(6) Å, c = 12.0771(3) Å, V=178.89 Å 3 , Z=1, D x =6.7235 g cm −3 , μ=1146.939 cm −1 (λ= 1.54051 Å), F(000) = 315.4, the structure was refined with 26 parameters to R wp =6.70%, R p =5.11% for 2926 step intensities and R b =7.83%, R f =6.70% for 131 peaks, “goodness of fit” S = 1.75. © 1994, Cambridge University Press. All rights reserved.