Synthesis, Structural, and Optical Characterization of a New Europium(II) Tin Selenide, Eu8(Sn4Se14)(Se3)2 with a (Sn4Se14)12– Building Block

Abstract

A new phase in europium-tin-chalcogenide chemistry has been prepared using the reactive flux method: Eu 8 -(Sn 4 Se 14 )(Se 3 ) 2 . The compound crystallizes in the orthorhombic space group P2 1 2 1 2 with cell parameters a = 11.990(2) A Ê , b = 16.425(4) A Ê , c = 8.543(1) A Ê , and Z = 2. Eu 8 (Sn 4 Se 14 )-(Se 3 ) 2 is a three dimensional structure with Eu II cations linked together with an unusual (Sn 4 Se 14 ) 12± anionic unit and (Se 3 ) 2± chains. UV-VIS-NIR band-gap analysis shows that these black metallic crystals are likely semiconductors with an optical band-gap of 1.07 eV.

Monoclinic Cu2Se3Sn

“…Since the metal-centred tetrahedra are connected only by the corners, the Se-centred coordination environment is also tetrahedral. Similar values of the Cu-Se and Sn-Se interatomic distances for tetrahedral surroundings are observed in the structures of LnCuSe 2 and Eu 2 SnSe 5 (Daszkiewicz et al, 2008;Evenson & Dorhout, 2001). However, from the bond-valence point of view the eight symmetry-independent Cu I ions are overbonded, because the bond-valence sums (BVS) for these ions [based on Cu-Se distances ranging from 2.380 (5) to 2.495 (5) Å ] are greater than the formal oxidation state, $1.40 (Table 1) (Brown, 1996).…”

The First Tetradentate μ‐1κ2:2κ2‐Sn2Se6 Ligand to a Lanthanide(III) Center: Solvothermal Syntheses and Characterizations of Lanthanide Selenidostannate Polymers with Tetraethylenepentamine as a Second Ligand

“…The complexes exhibit well‐defined steep absorption edges from which the band gaps ( E g ) can be estimated as 1.95, 2.12, and 2.34 eV for 1 , 2 , and 3 , respectively (Figure 8), indicating that the title complexes have semiconducting properties. The band gaps are smaller than that of the organic component free lanthanide polyselenidostannates Eu(Sn 4 Se 14 )(Se 3 ) 2 (1.07 eV) 21…”

The First Example of the Tetraselenidostannate Anion [SnSe4]4– as a Chelating Ligand to a Lanthanide Complex Ion: Solvothermal Synthesis and Characterization of Lanthanoid Selenidostannates [Hdien][Ln(dien)2(μ‐SnSe4)] (Ln = Sm, Eu) and [Eu2(dien)4(μ‐OH)2]Sn2Se6

“…The most related chelating coordination mode of the μ‐SnSe 4 ligand is observed in the [Cr(en) 2 (SnSe 4 )] – ion,6 but the [SnSe 4 ] 4– anion is more distorted in [Cr(en) 2 (SnSe 4 )] – owing to the formation of a nonplanar CrSe 2 Sn ring. The bond lengths Sm–Se [2.9468(7) Å] and Eu–Se [2.9345(9) Å] are shorter than those observed in nine‐coordinate lanthanide selenides, such as the bond lengths 2.9543(4)–3.2336(9) Å for the Sm–Se bond of the SmOSe 8 polyhedron in Sm 4 FeOSe 6 ,7 and 3.0575(9)–3.323(2) Å for the Eu–Se bond of the EuSe 9 polyhedron in Eu 8 (Sn 4 Se 14 )(Se 3 ) 2 8a and EuSbSe 3 8b. The Ln–N bond lengths are 2.590(5)–2.615(5) Å for Sm–N and 2.572(5)–2.597(6) Å for Eu–N (Table 1), and they are in the range observed in other Sm 3+ /Eu 3+ compounds with amino‐chelating ligands 2a,9.…”