Structural properties of the superconductor ${\mathrm{LaBa}}_2$${\mathrm{Cu}}_{3\mathrm{-}\mathrm{y}}$${\mathrm{O}}_{7\mathrm{-}\mathrm{z}}$ in the solid solution system ${\mathrm{La}}_{1+\mathit{x}}$${\mathrm{Ba}}_{2\mathrm{-}\mathit{x}}$${\mathrm{Cu}}_{3\mathrm{-}\mathit{y}}$${\mathrm{O}}_{7\mathrm{-}\mathit{z}}$

We present time-of-flight (TOF) neutron-powder-diffraction results of four samples in the solid-solution orthorhombic ${\mathrm{La}}_{1+\mathit{x}}$ ${\mathrm{Ba}}_{2\mathrm{-}\mathit{x}}$ ${\mathrm{Cu}}_{3\mathrm{-}\mathit{y}}$ ${\mathrm{O}}_{7\mathrm{-}\mathit{z}}$ system. The data for all of the samples were taken at room temperature. The average crystal structures of ${\mathrm{LaBa}}_2$ ${\mathrm{Cu}}_{2.90}$ ${\mathrm{O}}_{6.82}$ (${\mathit{T}}_{\mathit{c}}$=45 K), ${\mathrm{La}}_{1.56}$ ${\mathrm{Ba}}_{1.44}$ ${\mathrm{Cu}}_{2.86}$ ${\mathrm{BO}}_{6.98}$ (nonsuperconductor), and the impurity-free ${\mathrm{LaBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{6.85}$ ($T_c$=93 K) were refined by the Rietveld analysis which includes the refinement of the occupancies of the La and/or Ba atoms. The remaining sample was imhomogeneous ${\mathrm{LaBa}}_2$ ${\mathrm{Cu}}_{3\mathrm{-}\mathrm{y}}$ ${\mathrm{O}}_{7\mathrm{-}\mathrm{z}}$ ($T_c$=85 K).