CRYSTAL STRUCTURE OF ND3AG4XGE1.25-XSE7 (X = 0.05; 0.10; 0.15) CHALCOGENIDES
DOI:
https://doi.org/10.32782/pcsd-2024-3-3Keywords:
rare earth metals, chalcogenides, crystal structure, X-ray powder methodAbstract
Three samples of stoichiometric compositions Nd3Ag0.2Ge1.2Se7, Nd3Ag0.40Ge1.15Se7 і Nd3Ag0.60Ge1.10Se7, weighing one gram each, were obtained by sintering elementary high-purity in vacuumed quartz ampoules (1.33·10-2 Pa) at a maximum synthesis temperature 1150 °С. Crystal structure of Nd3Ag4xGe1.25-xSe7 selenides (x = 0.05; 0.10; 0.15): Nd3Ag0.2Ge1.2Se7 (a = 10.5661(1) Å, c = 6.0381(7) Å, RI = 0.0811, Rp = 0.1978), Nd3Ag0.4Ge1.15Se7 (a = 10.5863(4) Å, c = 6.0359(4) Å, RI = 0.0883, Rp = 0.2017) and Nd3Ag0.6Ge1.1Se7 (a = 10.6045(6) Å, c = 6.0446(5) Å, RI = 0.0880, Rp = 0.1904) was studied by X-ray powder method. The studied structures relate to the structural type La3CuSiS7 (SG P63; PS hP24). In their structure, Neodymium atoms are located in the site 6c (x y z) and, together with selenium atoms, form trigonal prisms with two additional atoms [Nd Se14Se23Se3] (CN = 8). Atoms of statistical mixtures R1 (0.20 Ge + 0.20 Ag), R2 (0.15 Ge + 0.40 Ag) and R3 (0.10 Ge + 0.60 Ag) occupying the site 2a (0 0 z) are located practically on one of the faces of the octahedron [R(Ag +Ge) 6Se]. Due to this, these atoms lie in the plane of triangles [M 3Se2]. Ge atoms localized in the site 2b (1/3 2/3 z) have a tetrahedral environment [Ge Se13Se3] of selenium atoms. Selenium in the crystal lattice has three atomic positions: Se1 (site 2b), Se2 and Se3 (site 6c). There are two formula units of Nd3Ag4xGe1.25-xSe7 per unit cell. Trigonal prisms [Nd 8Se] are connected by edges and form "blocks" (three prisms in each). Octahedra [R(Ag+Ge) 6Se] have common faces and form "columns" in the direction of the main axis. Trigonal prisms with octahedra form common faces. [Ge 4Se] tetrahedra are isolated from each other. When the content of argentum increases, the unit cell parameters increase due to the size factor. Germanium-containing selenides Nd3Ag4xGe1.25-xSe7 (x = 0.05; 0.10; 0.15) based on neodymium are promising chalcogenide phases on the basis of which materials for nonlinear optics can be created. Due to the presence of rare earth elements in the structure, materials based on such selenides can predictably have weak paramagnetic properties.
References
Gulay L., Lychmanyuk O. Crystal structure of the R3Si1.25Se7 (R = Pr, Nd and Sm) compounds. J. Alloys Compd. 2008. 458. P. 174–177. https://doi.org/10.1016/j.jallcom.2007.03.127
Смітюх О., Марчук О., Олексеюк І., Федорчук А. Кристалічна структура сполук Er1.5La(Pr)1.5Si1.67Se7. Вісн. Ужгор. нац. ун-ту. Серія «Хімія». 2017. 1(37). C. 44–47.
Daszkiewicz M., Smitiukh O., Marchuk O., Gulay L. The crystal structure of Er2.34La0.66Ge1.28S7 and the LaxRyGe3S12 phases (R – Tb, Dy, Ho and Er). J. Alloys Compd. 2018. 738. P. 263–269. https://doi.org/10.1016/j.jallcom.2017.12.207
Блашко Н., Марчук О., Смітюх О., Федорчук А. Кристалічна структура Pr3Ag4xGe1.25-xSe7 (x=0.10; 0.15). Вісн. Одеського ун-ту. Серія «Хімія». 2022. 27. 3(83). C. 27–35. https://doi.org/10.18524/2304-0947.2022.3(83).268609
Mei D., Yin W., Feng K., Lin Z., Bai L., Yao J., Wu Y. LiGaGe2Se6: A New IR Nonlinear Optical Material with Low Melting Point. Inorganic Chem. 2012. 51(2). P. 1035–1040. https://doi.org/10.1021/ic202202j
Yin W., Feng K., Hao W., Yao J., Wu Y. Syntheses, structures, and optical properties of Ba4MInSe6 (M = Cu, Ag). J. Solid State Chem. 2012. 192. P. 168–171. https://doi.org/10.1016/j.jssc.2012.03.068
Feng K., Zhang X., Yin W., Shi Y., Yao J., Wu Y. New Quaternary Rare-Earth Chalcogenides BaLnSn2Q6 (Ln = Ce, Pr, Nd, Q = S; Ln = Ce, Q = Se): Synthesis, Structure, and Magnetic Properties. Inorganic Chem. 2014. 53(4). P. 2248–2253. https://doi.org/10.1021/ic402934m
Hao W., Han Y., Huang R., Feng K, Yin W., Yao J., Wu Y. Ag1.75InSb5.75Se11: A new noncentrosymmetric compound with congruent-melting behavior. J. Solid State Chem. 2014. 218. P. 196–201. https://doi.org/10.1016/j.jssc.2014.06.026
Zhang X., Chen W., Mei D., Zheng C., Liao F., Li Y., Lin J., Huang F. Synthesis, structure, magnetic and photo response properties of La3CuGaSe7. J. Alloys Comp. 2014. 610. P. 671–675. https://doi.org/10.1016/j.jallcom.2014.05.086
Shi Y., Chen Y., Chen M., Wu L., Lin H., Zhou L., Chen L. Strongest Second Harmonic Generation in the Polar R3MTQ7 Family: Atomic Distribution Induced Nonlinear Optical Cooperation. Chem. Mat. 2015. 27(5). P. 1876–1884. https://doi.org/10.1021/acs.chemmater.5b00177
Kabanov A., Morkhova Y., Osipov V., Rothenberger M., Leisegang T., Blatov V. A novel class of multivalent ionic conductors with the La3CuSiS7 structure type: results of stepwise ICSD screening. Phys. Chem. Chem. Phys. 2024. 26(3). P. 2622–2628. https://doi.org/10.1039/D3CP04510B
Grin Y., Akselrud L. WinCSD: Software package for crystallographic calculations (Version 4). J. Appl. Cryst. 2014. 47(2). Р. 803–805. https://doi:10.1107/s1600576714001058
Momma, K., Izumi F. VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data. J. Appl. Cryst. 2011. 44(6). Р. 1272–1276. https://doi:10.1107/S0021889811038970
Guittard M., Julien-Pouzol M. Les composes hexagonaux de type La3CuSiS7. Bull. Soc. Chim. Fr. 1972. 3. P. 2207–2209.
Guittard M., Julien-Pouzol M. Les composes hexagonaux de type La3CuSiS7. Bull. Soc. Chim. Fr. 1970. 7. P. 2467–2469.
Shannon R. Revised effective ionic radii and systematic studied of interatomic distances in halides and chalcogenides. Acta Cryst. 1976. 39. P. 751–767. https://doi.org/10.1107/S0567739476001551
Wiberg N, Wiberg E, Holleman A. Lehrbuch der Anorganischen Chemie. Walter de Gruyter. 102. Auflage, 2007. P. 2003–2004.
