Crystal Structure, Thermal Behavior, and Luminescence of BaZnCl4-II:Sm2+ and Comparision to BaZnCl4-I:Sm2+

✍ Scribed by Claudia Wickleder

• Book ID: 102611214
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 473 KB
• Volume: 162
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9279

✦ Synopsis

Slightly di4erent reaction conditions lead to two modi5cations of single crystalline BaZnCl 4 . The crystal structure of BaZnCl 4 -II (orthorhombic, Pbcn (No. 60), Z ‫؍‬ 4, a ‫؍‬ 6.5041(9), b ‫؍‬ 15.363(3), c ‫؍‬ 6.819(1) A > , R all ‫؍‬ 0.0608) consists of edge and corner sharing [BaCl 8 ] polyhedra with [ZnCl 4 ] tetrahedra 5lling the holes of the [BaCl 8 ] network. The polyhedra in BaZnCl 4 -I are nearly equal but the linkage is di4erent. Both modi5cations can be obtained as single phases from BaCl 2 /ZnCl 2 mixtures and show no phase transitions down to 4 K. Emission spectra of both modi5cations doped with Sm 2؉ reveal 4 f 5 5d 1 P 7 F J as well as 5 D 0 P 7 F J transitions. In spite of the similar surrounding of Sm 2؉ in both modi5cations the shift of the maximum of the dPf emission is 450 cm ؊1 , showing that small changes in the coordination polyhedra of divalent rare earths cause large changes in luminescence properties.