Syntheses and Crystal Structures of Er2(SeO3)3 and Dy3(SeO3)4F

✍ Scribed by Ina Krügermann; Mathias S. Wickleder

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 437 KB
• Volume: 167
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9629

✦ Synopsis

The decomposition of Er 2 (SeO 4 ) 3 in the presence of LiF in a sealed gold ampoule at 8701C yielded single crystals of Er 2 (SeO 3 ) 3 . The triclinic crystal structure (P 1 1; Z ¼ 2; a ¼ 698:2ð1Þ; b ¼ 800:6ð1Þ; c ¼ 895:0ð1Þ pm; a ¼ 71:38ð1Þ; b ¼ 70:13ð1Þ; c ¼ 65:87ð1Þ1; R all ¼ 0:0364) contains two crystallographically different Er 3+ ions in seven-and eightfold coordination of oxygen atoms, respectively. The distances Er-O range from 220 to 256 pm. Each of the three crystallographically different selenite groups connects four Er 3+ ions with each other. The analogous reaction with Dy 2 (SeO 4 ) 3 did not lead to the anhydrous selenite but to single crystals of the selenite fluoride Dy 3 (SeO 3 ) 4 F. In the hexagonal crystal structure (P6 3 mc; Z ¼ 2; a ¼ 1035:96ð13Þ; c ¼ 686:47ð7Þ pm; R all ¼ 0:0305), one SeO 2À 3 group and an F À ion act as l 3 ligands connecting three Dy 3+ ions to triangles. The Dy 3+ ions are coordinated by eight oxygen atoms and one fluoride ion with distances between 234 and 256 pm. The crystal structures are strongly influenced by the lone pairs of the SeO 2À 3 ions. The IR spectra show the typical frequencies for selenite groups. # 2002 Elsevier Science (USA)