Extraordinarily Short Pb–Pb Bonds in the New Binary Intermetallic Ti6Pb4.8

✍ Scribed by Holger Kleinke

• Book ID: 102610610
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 375 KB
• Volume: 159
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9141

✦ Synopsis

Ti 6 Pb 4.8 is accessible via reactions in a Pb 6ux starting from the elements in evacuated silica tubes at 6803C. Larger single crystals can be obtained by adding traces of iodine to promote crystal growth. At higher temperatures, Ti 6 Pb 4.8 decomposes into Ti 4 Pb and Pb. Ti 6 Pb 4.8 crystallizes in the hexagonal -Ti 6 Sn 5 type, space group P6 3 /mmc, with the lattice dimensions a ‫؍‬ 939.23(8) and c ‫؍‬ 579.01( 5) pm for Ti 6 Pb 4.824(7) (Z ‫؍‬ 2). While the structure is dominated by the heteronuclear Ti+Pb bonds, linear Ti and Pb chains run parallel to the c axis with interatomic distances being equidistant by symmetry c/2 ‫؍‬ 289.5 pm). This results in a Pb+Pb distance being much shorter than a Pb+Pb single bond (typically 310 pm). Longer homonuclear distances of about 315 pm (Ti+Ti) and between 357 and 374 pm (Pb+Pb) occur perpendicular to the chain direction. All these interactions have bonding character, as the LMTO calculations of Ti 6 Pb 4.8 reveal.