Regularities of the property changes in the compounds EuLnCuS3 (Ln = La-Lu)

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies

“…Despite that EuYCuSe 3 belongs to the same structural type as EuLnCuSe 3 (Ln = Sm-Ho), and the yttrium ion radius is less than that of holmium, the unit cell parameters of the yttrium-based selenide are larger than those for EuDyCuSe 3 and EuHoCuSe 3 , which is in agreement with the data obtained for isostructural quaternary sulfides ALnCuS 3 (A = Sr, Eu) [10,42,68,69]. This can be explained by the electronic structure of yttrium, which is a d-element.…”

“…In the structures of EuLnCuSe 3 (Ln = Sm, Gd, Tb, Dy, Ho, Y; structural type Eu 2 CuS 3 ), six Eu-Se distances, namely two Eu-Se1 i , two Eu-Se2 i and two Eu-Se3 i , are shorter than 3.2 Å, while the seventh and the longest distance Eu-Se3 ii gradually increases in the following sequence: 3.331 Å (EuSmCuSe 3 ) → 3.359 Å (EuGdCuSe 3 ) → 3.384 Å (EuTbCuSe 3 ) → 3.412 Å (EuDyCuSe 3 ) → 3.424 Å (EuYCuSe 3 ) → 3.507 Å (EuHoCuSe 3 ) (Figure 3, Table S4 in the Supplementary Materials). A similar trend was observed for isostructural compounds EuLnCuS 3 [10] and SrLnCuS 3 [67].…”

“…Particularly, changing the coordination polyhedron from the monocapped trigonal prism LnSe 7 in EuLaCuSe 3 to the LnSe 6 octahedron (Ln = Eu-Y) leads to the change in the structural type Ba 2 MnS 3 to Eu 2 CuS 3 , and the monocapped trigonal prism EuSe 7 in EuLnCuSe 3 (Ln = Eu-Y) to the trigonal prism EuSe 6 in EuLnCuSe 3 (Ln = Tm-Lu) leads to the change in the structural type Eu 2 CuS 3 to KZrCuS 3 . A similar change in the structural types was observed for SrLnCuSe 3 (Ln = La-Lu) [26][27][28]36,42] and EuLnCuS 3 [10]. Thus, the change in the structural type in EuLnCuSe 3 is dictated by the size of the Ln 3+ cation.…”

“…Finally, a similarity in the structural types of EuLnCuSe 3 and SrLnCuSe 3 could be observed, since the radius of Eu 2+ (1.17 Å, coordination number = 6 [61]) is close to the radius of Sr 2+ (1.18 Å, coordination number = 6 [61]), which was observed for the sulfides EuLnCuS 3 [10] and SrLnCuS 3 [51]. For a series of selenides SrLnCuSe 3 (Ln = La-Lu, Y, Sc), the existence of three structural types Ba 2 MnS 3 , Eu 2 CuS 3 and KZrCuS 3 (Table S1 in the Supplementary Materials) was experimentally established [26][27][28]36,42].…”

“…Nowadays, the copper-containing chalcogenides are of particular interest and in the limelight of many studies, the reason being their thermal, electrical and optical properties, which make them promising materials for infrared (IR) and nonlinear optics [1,2], photocatalysis, photoelectric energy and proton conductivity [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Development of electronic technologies opened prospects for the copper containing selenides as one of the most promising absorbers in thin film photovoltaic cells and high-performance thermoelectric materials [19,20].…”