Quantitative Analysis of Coexisting Byproducts in Orthorhombic YBa ₂ Cu ₃ O x by X‐ray Diffraction

BaCuO 2 , Y 2 Cu 2 O 5 , and Y 2 BaCuO 5 as well as YBa 2 Cu 3 O x were synthesized and nonlinear calibration curves for mole fraction versus integrated intensity ratio of X‐ray diffraction peaks were obtained for BaCuO 2‐ , Y 2 Cu 2 O 5‐ , and Y 2 BaCuO 5‐ YBa 2 Cu 3 O x systems. It is shown that the amount of BaCuO 2 contained in orthorhombic YBa 2 Cu 3 O x is not negligible, even if the relative intensity of the strongest diffraction peak of BaCuO 2 is negligibly weak.