Syntheses, Structures, Magnetism, and Optical Properties of Lutetium-Based Interlanthanide Selenides

• Published in: Inorganic chemistry Vol. 46; no. 22; pp. 9213 - 9220
• Main Authors: Jin, Geng Bang, Choi, Eun Sang, Guertin, Robert P, Brooks, James S, Booth, Corwin H, Albrecht-Schmitt, Thomas E
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 29.10.2007
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic701012j

Ln3LuSe6 (Ln = La, Ce), β-LnLuSe3 (Ln = Pr, Nd), and Ln x Lu4 - x Se6 (Ln = Sm, Gd; x = 1.82, 1.87) have been synthesized using a Sb2Se3 flux at 1000 °C. Ln3LuSe6 (Ln = La, Ce) adopts the U3ScS6-type three-dimensional structure, which is constructed from two-dimensional slabs with the gaps between these slabs being filled by octahedrally coordinated Lu3+ ions. The series of β-LnLuSe3 (Ln = Pr, Nd) are isotypic with UFeS3. Their structures include layers formed from LuSe6 octahedra that are separated by eight-coordinate Ln3+ (Ln = Pr, Nd) ions in bicapped trigonal prismatic environments. Sm1.82Lu2.18Se6 and Gd1.87Lu2.13Se6 crystallize in the disordered F-Ln2S3 type structure with the eight-coordinate bicapped trigonal prismatic Ln(1) ions residing in the one-dimensional channels formed by three different double chains via edge- and corner-sharing. These double chains are constructed from Ln(2)Se7 monocapped trigonal prisms, Ln(3)Se6 octahedra, and Ln(4)S6 octahedra, respectively. The magnetic susceptibilities of β-PrLuSe3 and β-NdLuSe3 follow the Curie−Weiss law. Sm1.82Lu2.18Se6 shows van Vleck paramagnetism. Magnetic susceptibility measurements show that Gd1.87Lu2.13Se6 undergoes an antiferromagnetic transition around 4 K. Ce3LuSe6 exhibits soft ferromagnetism below 5 K. The optical band gaps for La3LuSe6, Ce3LuSe6, β-PrLuSe3, β-NdLuSe3, Sm1.82Lu2.18Se6, and Gd1.87Lu2.13Se6 are 1.26, 1.10, 1.56, 1.61, 1.51, and 1.56 eV, respectively.