A One-Dimensional Cuprate Closely Related to the "0212"-Structure: Nd2Ba4Cu2O9

✍ Scribed by B. Domengès; F. Abbattista; C. Michel; M. Vallino; L. Barbey; N. Nguyen; B. Raveau

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 604 KB
• Volume: 106
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1993.1286

✦ Synopsis

The structure of the cuprate (\mathrm{Nd}{2} \mathrm{Ba}{4} \mathrm{Cu}{2} \mathrm{O}{4}) has been determined using both (\mathrm{X})-ray powder diffraction and high resolution electron microscopy. The compound crystallizes in the space group (P \overline{4} n 2) with (a=12.072, c=3.874 \AA). The structure consists of isolated chains of corner-sharing (\mathrm{CuO}{5}) pyramids whose cohesion is ensured by the presence of (\mathrm{Nd}^{3+}) and (\mathrm{Ba}^{2+}) cations, the coordination of which can be described as distorted monocapped trigonal prisms (\mathrm{BaO}{7}) and (\mathrm{NdO}{7}). A description of the structure in terms of pyramidal copper chains sharing their corners with (\mathrm{NdO}{5}) tetragonal pyramids is also given. The resulting three-dimensional framework (\left[\mathrm{Nd}{2} \mathrm{Cu}{2} \mathrm{O}{8}\right]{x}) forms octogonal tunnels where the barium cations and the additional oxygen are located. The close relationships between this one-dimensional cuprate and the layered cuprates are discussed. O 1993 Acadenic Press, Inc.