2004/11/12 by V. I. Belyi, V. I. Belyĭ, В.Н. Икорский +8
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Lanthanide and Transition Metal Complexes #Materials Science (cond-mat.mtrl-sci) #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0411327
9 pages, 6 figures
arxiv created 2004/11/12 · openalex publication_date 2004/11/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A comparative study of the crystalline and molecular structures of trifluoroacetate trihydrates of Tb(III) prepared from Tb(OH)3 and Tb2(CO3)3 by reaction with trifluoroacetic acid is made. Elemental analysis of the two reaction products in indicated them to be compounds of the same C6H6F9O9Tb. According to the X-ray structural analysis the molecular structure of the first product is described by the average statistical formula Tb2(CF3COO)5(CF3COOH)(H2O)5(OH) (Tb-I) and the compound is a dimer with a centre of inversion. In the second case the product is also a centrosymmetric dimer but its formula is Tb2(CF3COO)6(H2O)6 (Tb-II). The compounds only difference is in the crystallographic positions of their hydrogen atoms. A luminescent analysis using Tb3+ 5D4-> 7F0 transition indicated the presence within the structure of Tb-I of the structure of Tb-II. Magnetic measurements showed that Tb-II has an antiferromagnetic ordering at low temperatures. In the case of Tb-I there also appears a ferromagnetic ordering. On the basis of the available experimental results such a behaviour was explained to be the result of some peculiar features of the hydrogen bonds in the molecules.