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The crystal structure of Er2.34La0.66Ge1.28S7 and the LaxRyGe3S12 phases (R – Tb, Dy, Ho and Er)
Journal of Alloys and Compounds 738 (2018) 263e269
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The crystal structure of Er2.34La0.66Ge1.28S7 and the LaxRyGe3S12 phases (R e Tb, Dy, Ho and Er) M. Daszkiewicz a, O.V. Smitiukh b, O.V. Marchuk b, *, L.D. Gulay c a
Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P. O. Box 1410, 50-950 Wrocław, Poland Department of Inorganic and Physical Chemistry, Eastern European National University, Voli Ave 13, 43025 Lutsk, Ukraine c Department of Ecology and Protection of Environment, Eastern European National University, Voli Ave 13, 43025 Lutsk, Ukraine b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 17 October 2017 Received in revised form 8 December 2017 Accepted 19 December 2017 Available online 20 December 2017
Isothermal section of the Er2S3eLa2S3eGeS2 system at 770 K was investigated. The phase boundaries of the solid solution La4e4xR4xGe3S12 (x ¼ 0e0.75, R e Tb, Dy, Ho and Er) were determined, and their structure was investigated by single crystal and powder X-ray diffraction. The existence of new quaternary compound Er2.34La0.66Ge1.28S7 was established and its crystal structure was determined by X-ray single crystal diffraction (space group Р63, Pearson symbol hР24e1.44, a ¼ 0.96934(3) nm, c ¼ 0.58680(2) nm, R1 ¼ 0.0220). © 2017 Elsevier B.V. All rights reserved.
Keywords: Chalcogenides Rare earth compounds Crystal structure X-ray powder diffraction
1. Introduction The development of modern inorganic chemistry and semiconductor material science is associated with the design of new materials that would possess pre-set functional properties. One approach to find new substances with semiconductor properties is to study the interaction of the components of complex chalcogenide systems [1]. The study of the composition-structure-property relationship of a substance as well as the determination of its thermodynamic conditions of existence is one of the tasks of physico-chemical analysis. The information about the crystalline structure of a compound not only provides some data on interatomic distances and the coordination surrounding of atoms but also makes possible certain assumptions and conclusions about the mechanisms of chemical transformations and predictions on the synthesis of new substances. The crystal structure is one of the fundamental characteristics of a compound that determines a range of its physicochemical properties. The accumulation of experimental data on the conditions for the
* Corresponding author. E-mail address: [email protected] (O.V. Marchuk). https://doi.org/10.1016/j.jallcom.2017.12.207 0925-8388/© 2017 Elsevier B.V. All rights reserved.
formation and existence of compounds makes the process of designing new materials on their basis more purposeful [2]. Presented work is one of the stages of the systematic study of the interaction of components in complex sulfide systems R2S3eR'2S3eDIVS2 (DIV e Si, Ge, Sn; R e Lanthanide) and of determination of the crystal structure of the compounds formed therein [3]. Principal crystallographic characteristics of the binary and of the ternary components of the quasi-quaternary system Er2S3eLa2S3eGeS2 are shown in Table 1. 2. Experimental details A total of 63 samples were synthesized for the investigation of the system. The samples for the studies were prepared of the individual components of semiconductor purity. The alloys were synthesized in evacuated quartz containers in an MP-30 programmable electrical muffle furnace by heating to 1423 К at a rate of 12 К/h; exposure at 1423 К for 4 h; cooling to 770 К at a rate of 12 К/h; homogenizing and annealing at 770 К for 240 h; and finally quenching into cold water. Powder XRD patterns to determine the phase composition of synthesized alloys were recorded at a DRON 4-13 diffractometer in the range 2Q ¼ 10e80 (CuKa radiation, scan step 0.05 , 4 s exposure at each point). The data were processes using WinCSD
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Table 1 Crystallographic characteristics of the binary and of the ternary components of the quasi-quaternary system Er2S3eLa2S3eGeS2. Compound
Er2S3 La2S3 GeS2 GeS2 Er3Ge1.33S7 La2GeS5 La3Ge1.25S7 La4Ge3S12 ErLaS3 Er3LaS6
Space group
P21/m Pnma P21/с Fdd2 Р63 P21/с Р63 R3c Pnma P21/m
Lattice parameters, nm
Ref.
a
b
c
1.0072 0.766 0.6720 1,68 1.02970 0.7641 1.0297 1.940 1.6510 1.095
0.3976 b ¼ 98.66 0.422 1.6101 b ¼ 90.88 2238 e 1.2702 b ¼ 101.39 e e 0.3996 1.126 b ¼ 108.6
1.7389 0.1595 1.1436 0,687 0.58120 0.7893 0.58120 0.810 2.12597 0.398
[4] [5] [6] [7] [8] [9] [8] [9] [10] [11]
software package [12]. The investigation of the crystal structure of the quaternary phases was performed using X-ray single crystal diffraction. The Xray intensities data were collected on a Oxford Diffraction X'calibur four-circle single-crystal X-ray diffractometer with CCD Atlas detector, using graphite-monochromatized MoKa radiation (l ¼ 0.071073 nm). The raw data were treated with the CrysAlis Data Reduction program taking into account an absorption correction. The intensities of the reflections were corrected for Lorentz and polarization factors. The crystal structure was solved by Patterson methods and refined by the full-matrix least-squares method using SHELXL-2014 [13]. Acentric space groups were checked with the PLATON program, and no additional symmetry elements were found [14]. 3. Results and discussion Literature sources report the existence of GeS2 in two modifications, with the phase transition temperature of 770 K. We have identified at the annealing temperature the monoclinic modification of GeS2 (P21/с). The investigation of the quasi-quasiternary system Er2S3eLa2S3eGeS2 confirms the existence of three ternary compounds, La4Ge3S12 (space group R3c, own structure type),
Fig. 1. Isothermal section of the quasi-ternary system Er2S3eLa2S3eGeS2 at 770 K.
Table 2 Crystallographic data and structure refinement details for the Er2.34La0.66Ge1.28S7 compound. Empirical formula Formula weight Space group Unit cell dimensions: a (nm) c (nm) V (nm3) Number of formula units per unit cell Calculated density Absorption coefficient F(000) Crystal color Crystal size Q range for data collection Index ranges
Reflections collected Independent reflections Refinement method Absolute structure parameter Data/restraints/parameters Goodness-of-fit on F2 Final R indices [I>2s(I)] R indices (all data) Extinction coefficient Largest diff. peak and hole 103
Er2.34La0.66Ge1.28S7 800.45 P63 (No 173) 0.96934(3) 0.58680(2) 0.47749(3) 2 5.572 28.754 700 black 0.055 0.029 0.024 mm 2.426e26.702 12 h 12 12 h 12 7 l 7 7908 686 [R(int.) ¼ 0.0490] Full-matrix least-square on F2 0.35(2) 686/1/40 1.062 R1 ¼ 0.0220 wR2 ¼ 0.0448 R1 ¼ 0.0229 wR2 ¼ 0.0450 e 0.683 and 0.974 e/nm3
La2GeS5 (space group P21/c, own structure type), La3Ge1.25S7 (space group P63, structure type Dy3Ge1.25S7). No ternary compounds were observed in the Er2S3eGeS2 section. A part of the isothermal section of the Er2S3eLa2S3eGeS2 system at 770 K is presented in Fig. 1. A ternary phase Er3Ge1.33S7 was reported in Ref. [8] in the EreGeeS system outside the Er2S3eGeS2 section. We synthesized and annealed nine alloys of the composition Er3exLaxGe1.25S7 (x ¼ 0e0.7) and tested their phase composition. The synthesis of samples was according to the procedure described in the Experimental section. The formation of new quaternary compound of approximate composition Er2.4La0.6Ge1.25S7 was observed. A single crystal from the Er2.4La0.6Ge1.25S7 sample was selected to study its crystalline structure. Performed investigation determined the composition of the new quaternary phase as Er2.34La0.66Ge1.28S7 (structure type Dy3Ge1.25S7, space group P63, Pearson symbol hР24e1.44). Crystallographic data and structure refinement details for the Er2.34La0.66Ge1.28S7 compound are given in Table 2. Atomic coordinates and thermal displacement parameters are given in Table 3, and the interatomic distances are listed in Table 4. The position M of the mixture of randomly distributed La and Er atoms in the Er2.34La0.66Ge1.28S7 structure corresponds to the position of Dy in the structure of Dy3Ge1.25S7. The positions of Ge and S are the same in both structures. The unit cell projection and the coordination environment of atoms in the structure of the compound Er2.34La0.66Ge1.28S7 are depicted in Fig. 2. The atoms of the statistical mixture M (ErþLa) occupy the 6c site and are located in monocapped trigonal prisms with coordination number (6 þ 1). The Ge atoms are located in sites 2b and 2a which have octahedral and tetrahedral surrounding of sulfur atoms respectively. Sulfur atoms (6c and 2b sites) are coordinated by tetrahedra of cations. The existence at 770 K of the solid solution range of La4Ge3S12 (space group R3c, Pearson symbol hR38) was found in the quasiternary system Er2S3eLa2S3eGeS2; its extent is La4e4xEr4xGe3S12 (x ¼ 0e0.63). Additionally, we studied the extent of solid solutions in the
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Table 3 Atomic coordinates and thermal displacement parameters for the Er2.34La0.66Ge1.28S7 compound. Atom
Site
x/a
y/b
z/c
Ueq 102, nm2
U11
U22
U33
U23
U13
U12
M* Ge1 *Ge2 S1 S2 S3
6c 2b 2a 6c 6c 2b
0.21319(7) 1/3 0 0.2533(5) 0.4747(5) 1/3
0.35880(7) 2/3 0 0.1053(4) 0.5693(5) 2/3
0.5443(2) 0.1199(3) 0.2296(13) 0.4911(7) 0.2778(5) 0.7475(10)
0.0254(2) 0.0138(7) 0.009(3) 0.0288(12) 0.0197(9) 0.0168(14)
0.0185(3) 0.0170(10) 0.006(3) 0.0229(19) 0.023(2) 0.019(2)
0.0168(4) 0.0170(10) 0.006(3) 0.0176(18) 0.032(2) 0.019(2)
0.0391(4) 0.0073(10) 0.015(6) 0.045(3) 0.0122(15) 0.012(3)
0.0002(5) 0 0 0.0018(2) 0.0034(18) 0
0.0029(5) 0 0 0.0145(17) 0.0031(17) 0
0.0075(3) 0.0085(5) 0.0032(15) 0.0098(15) 0.0194(19) 0.0096(11)
*M e 0.78(3) Er þ 0.22(3) La. *Ge2 e 0.285(10) Ge. Ueq. is defined as one third of the trace of the orthogonalized Uij tensor. The anisotropic temperature factor exponent takes the form: 2p2[h2a*2U11 þ … þ 2hka*b*U12].
Table 4 Interatomic distances (d) and coordination numbers (C.N.) of atoms in the structure of the compound Er2.34La0.66Ge1.28S7. Atoms M
Ge1 Ge2 S1
S2
S3
e e e e e e e e e e e e e e e e e e e e
S1 S1 S1 S2 S3 S2 S2 S3 3S2 3S1 3S1 Ge2 M M M Ge1 M 2M Ge1 3M
d (nm)
C.N.
0.2692(4) 0.2737(4) 0.2770(4) 0.2804(4) 0.2865(3) 0.2868(4) 0.3067(4) 02186(6) 0.2218(4) 0.2554(6) 0.2631(6) 0.2554(6) 0.2737(4) 0.2770(4) 0.3367(4) 0.2288(4) 0.2868(4) 0.3067(4) 0.2186(6) 0.2865(3)
7
4 6 4
4
4
related systems La4Ge3S12e“R4Ge3S12” (R e Tb, Dy and Ho). The maximum range is observed in the La4Ge3S12e“Tb4Ge3S12” system. The change of the cell parameters within the La4e4xR4xGe3S12 solid solution ranges (R e Tb, Dy, Ho and Er) is plotted in Fig. 3. The variation in the maximum content of Tb, Dy, Ho and Er components in a solid solution range of La4Ge3S12 is associated with an reduction in the atomic radii of the elements; rare-earth cations with the closest to La3þ radius are most likely to substitute La atoms. The crystal structure of the La4e4xR4xGe3S12 solid solution (R e Tb, Dy, Ho and Er) was investigated using X-ray single crystal diffraction. Single crystals for the investigation were selected from the samples with the compositions La2R2Ge3S12 (R e Tb, Dy, Ho and Er). Results of the crystal structure determination of La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12 are presented in Table 5, where the atomic coordinates and thermal displacement parameters are given in Table 6 and interatomic distances are collected in Table 7. Two mixtures of the randomly distributed R and La atoms (M1 and M2) exist for all structures. Obtained data agree well with reported in Ref. [2] results for La4e4xY4xGe3S12 (x ¼ 0) solid solution. Unit cell projection and the coordination environment of atoms in the structure of the quaternary phases La4e4xR4xGe3S12 (R e Tb,
Fig. 2. Unit cell and coordination polyhedra in the structure of the compound Er2.34La0.66Ge1.28S7.
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Fig. 3. Variation of the rhombohedral cell parameters within the solid solution ranges La4e4xR4xGe3S12: а) R ¼ Tb (x ¼ 0e0.72); b) R ¼ Dy (x ¼ 0e0.70); c) R ¼ Ho (x ¼ 0e0.60); d) R ¼ Er (x ¼ 0e0.63).
Dy, Ho and Er) are shown in Fig. 4. The M1 (6a site) and M2 (18b site) atoms are located in trigonal and bi-capped trigonal prisms respectively. The Ge atoms (18b site) have a tetrahedral surrounding of sulfur atoms. The S1 and S4 atoms are surrounded by three atoms. Both S2 and S3 atoms are located in tetrahedra. Mixed M1 site prefers the small R cation and the M2 site prefers the large La
cation, similar to the La:Y analog. 4. Conclusion A new quaternary compound Er2.34La0.66Ge1.28S7 was found in the investigation of the isothermal section of the quasi-ternary
Table 5 Results of the crystal structure determination of La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12. Empirical formula
La2.02Tb1.98Ge3S12
La2.64Dy1.36Ge3S12
La2.25Ho1.75Ge3S12
La2.16Er1.84Ge3S12
Space group Formula weight Unit cell dimensions: a (nm) c (nm) V (nm3) Number of formula units per unit cell Calculated density Absorption coefficient F(000) Crystal color Crystal size Q range for data collection Index ranges
R3c (No 161) 1197.84
R3c (No 161) 1190.21
R3c (No 161) 1203.77
R3c (No 161) 1210.39
1.92627(5) 0.79263(2) 2.54705(16) 6 4.685 19.781 3191 yellow 0.162 0.128 0.103 mm 3.664e28.275 25 h 23 25 k 25 10 l 10 7177 1372 [R(int.) ¼ 0.0229] Full-matrix least-square on F2 0.018(10) 1372/1/60 1.090 R1 ¼ 0.0141 wR2 ¼ 0.0290 R1 ¼ 0.0151 wR2 ¼ 0.0293 e 0.429 and 0.710 e/nm3
1.92868(5) 0.79498(2) 2.56099(14) 6 4.630 18.978 3169 yellow 0.192 0.106 0.052 mm 3.660e27.450 24 h 21 23 k 24 10 l 10 6175 1287 [R(int.) ¼ 0.0490]
1.92448(6) 0.79096(4) 2.5370(2) 6 4.727 20.360 3201 black 0.301 0.078 0.071 mm 3.668e27.470 24 h 24 24 k 24 9 l 10 5780 1263 [R(int.) ¼ 0.0214]
1.92165(4) 0.78757(2) 2.51866(13) 6 4.788 21.228 3218 yellow 0.374 0.074 0.039 mm 3.673e27.473 24 h 23 24 k 24 10 l 10 7267 1270 [R(int.) ¼ 0.0255]
0.005(9) 1287/1/60 1.128 R1 ¼ 0.0151 wR2 ¼ 0.0296 R1 ¼ 0.0158 wR2 ¼ 0.0298 e 0.478 and 0.830 e/nm3
0.015(8) 1263/1/60 1.072 R1 ¼ 0.0133 wR2 ¼ 0.0258 R1 ¼ 0.0140 wR2 ¼ 0.0259 e 0.350 and 0.481 e/nm3
0.027(10) 1270/1/60 1.122 R1 ¼ 0.0155 wR2 ¼ 0.0360 R1 ¼ 0.0159 wR2 ¼ 0.0362 e 0.492 and 0.959 e/nm3
Reflections collected Independent reflections Refinement method Absolute structure parameter Data/restraints/parameters Goodness-of-fit on F2 Final R indices [I>2s(I)] R indices (all data) Extinction coefficient Largest diff. peak and hole 103
Table 6 Atomic coordinates and thermal displacement parameters for La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12. Atom
Site
z/c
Ueq 102, nm2
U11
U22
U33
U23
U13
U12
0 0.23214(2) 0.18612(3) 0.17791(9) 0.05962(9) 0.20154(9) 0.27040(9) þ 0.867(18) Tb; þ 0.371(14) Tb.
0 0.00481(2) 0.19854(3) 0.28680(8) 0.12026(9) 0.11378(9) 0.27465(9)
0.00000(6) 0.29107(5) 0.34133(7) 0.50334(19) 0.2509(2) 0.50011(19) 0.14436(18)
0.01507(16) 0.01602(10) 0.01108(17) 0.0181(3) 0.0156(3) 0.0162(3) 0.0171(3)
0.0172(2) 0.01492(17) 0.0106(3) 0.0213(8) 0.0129(7) 0.0249(9) 0.0124(7)
0.0172(2) 0.01895(18) 0.0098(3) 0.0120(7) 0.0119(7) 0.0154(7) 0.0199(8)
0.0108(2) 0.01843(17) 0.0132(3) 0.0217(8) 0.0205(8) 0.0151(7) 0.0175(7)
0 0.00704(1) 0.0013(2) 0.0011(6) 0.0007(6) 0.0002(5) 0.0063(6)
0 0.00681(1) 0.0021(2) 0.0056(6) 0.0017(5) 0.0015(6) 0.0045(6)
0.00862(10) 0.01165(14) 0.0053(3) 0.0088(6) 0.0051(6) 0.0150(7) 0.0070(6)
0 0.23180(2) 0.18617(4) 0.17763(11) 0.06020(10) 0.20135(11) 0.27045(10) þ 0.649(17) Dy; þ 0.237(12) Dy.
0 0.00440(2) 0.19870(4) 0.28681(10) 0.12063(10) 0.11384(10) 0.27455(11)
0.00002(6) 0.29217(5) 0.34239(8) 0.5037(2) 0.2507(2) 0.5012(2) 0.1456(2)
0.01332(19) 0.01431(11) 0.01012(19) 0.0167(4) 0.0143(4) 0.0153(4) 0.0154(4)
0.0160(2) 0.0139(2) 0.0101(4) 0.0206(9) 0.0113(8) 0.0243(10) 0.0121(9)
0.0160(2) 0.0174(2) 0.0093(4) 0.0120(8) 0.0125(8) 0.0145(8) 0.0180(9)
0.0080(3) 0.01537(18) 0.0111(3) 0.0181(9) 0.0190(9) 0.0126(8) 0.0147(8)
0 0.00652(2) 0.0011(3) 0.0003(7) 0.0014(7) 0.0012(7) 0.0062(7)
0 0.00619(2) 0.0019(3) 0.0054(7) 0.0012(7) 0.0013(7) 0.0038(7)
0.00800(12) 0.01061(18) 0.0049(3) 0.0085(7) 0.0058(7) 0.0139(8) 0.0066(7)
0 0.23235(2) 0.18600(4) 0.17798(10) 0.05927(9) 0.20170(10) 0.27032(9) þ 0.784(16) Ho; þ 0.323(11) Ho.
0 0.00512(2) 0.19840(3) 0.28676(9) 0.12012(9) 0.11377(9) 0.27474(10)
0.00000(5) 0.29028(4) 0.34061(7) 0.50298(19) 0.2511(2) 0.49982(18) 0.14319(18)
0.01514(17) 0.01557(10) 0.01083(17) 0.0188(4) 0.0156(3) 0.0164(3) 0.0171(4)
0.0179(2) 0.01454(18) 0.0107(3) 0.0224(8) 0.0120(7) 0.0255(9) 0.0137(8)
0.0179(2) 0.01920(19) 0.0097(3) 0.0124(7) 0.0132(7) 0.0159(8 0.0206(8)
0.0095(2) 0.01722(15) 0.0124(3) 0.0223(8) 0.0208(7) 0.0140(7) 0.0161(7)
0 0.00705(13) 0.0014(2) 0.0007(6) 0.0004(6) 0.0012(6) 0.0077(6)
0 0.00671(13) 0.0025(2) 0.0069(6) 0.0022(6) 0.0015(6) 0.0057(6)
0.00897(11) 0.01162(15) 0.0053(3) 0.0091(7) 0.0058(6) 0.0152(7) 0.0078(7)
0 0.23269(2) 0.18583(4) 0.17814(12) 0.05862(10) 0.20200(11) 0.27028(11) þ 0.800(18) Er; þ 0.348(13) Er.
0 0.00561(2) 0.19819(4) 0.28665(10) 0.11948(11) 0.11378(11) 0.27482(11)
0.00000(7) 0.28909(5) 0.3395(9) 0.5030(3) 0.2514(3) 0.4996(2) 0.1414(2)
0.0156(2) 0.01575(13) 0.0106(2) 0.0197(4) 0.0156(4) 0.0159(4) 0.0174(4)
0.0184(2) 0.0142(2) 0.0104(4) 0.0227(9) 0.0115(8) 0.0235(10) 0.0140(9)
0.0184(2) 0.0196(2) 0.0090(3) 0.0119(8) 0.0121(8) 0.0149(8) 0.0207(9)
0.0099(3) 0.0176(2) 0.0130(3) 0.0248(10) 0.0218(9) 0.0154(8) 0.0178(9)
0 0.00745(15) 0.0016(3) 0.0011(7) 0.0001(7) 0.0015(7) 0.0079(7)
0 0.00701(15) 0.0029(3) 0.0090(7) 0.0022(7) 0.0024(7) 0.0064(7)
0.00921(12) 0.01162(16) 0.0052(3) 0.0088(7) 0.0048(7) 0.0143(7) 0.0088(7)
M. Daszkiewicz et al. / Journal of Alloys and Compounds 738 (2018) 263e269
La2.02Tb1.98Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.133(18) La M2* e 0.629(14) La La2.64Dy1.36Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.351(17) La M2* e 0.763(12) La La2.25Ho1.75Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.216(16) La M2* e 0.677(11) La La2.16Er1.84Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.200(18) La M2* e 0.652(13) La
y/b
x/a
Ueq. is defined as one third of the trace of the orthogonalized Uij tensor. The anisotropic temperature factor exponent takes the form: 2p2[h2a*2U11 þ … þ 2hka*b*U12].
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Table 7 Interatomic distances (d) and coordination numbers (C.N.) of atoms in the structures of La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12. La2.02Tb1.98Ge3S12 Atoms M1*
e3S2 e3S2
M2*
eS4 eS1 eS4 eS2 eS3 eS1 eS3
Ge
eS3
eGe eM2 eM2 eGe e2M1 eM2 eGe eM1 eM2 eM2
S4
0.28146(15) 0.28250(16)
6
M1*
0.28515(15) 0.28964(15)
7
M2*
eGe eM2 eM2
La2.25Ho1.75Ge3S12
d (nm)
C.N.
Atoms
e3S2 e3S2
0.28260(18) 0.28342(18)
6
M1*
eS4 eS1
0.28539(17) 0.29093(18)
7
M2*
0.29079(15)
eS4
0.29230(15) 0.29557(15)
La2.16Er1.84Ge3S12
d (nm)
C.N.
Atoms
d (nm)
C.N.
e3S2 e3S2
0.28080(15) 0.28200(16)
6
M1*
e3S2 e3S2
0.27904(19) 0.2806(2)
6
eS4 eS1
0.28512(15) 0.28888(16)
7
M2*
eS4 eS1
0.28491(18) 0.28770(19)
7
0.29098(17)
eS4
0.29044(16)
eS4
0.28986(19)
eS2
0.29326(17)
eS2
0.29145(15)
eS2
0.29050(18)
eS3
0.29663(17)
eS3
0.29497(15)
eS3
0.29398(18)
0.29668(17)
eS1
0.29766(18)
eS1
0.29614(17)
eS1
0.2947(2)
0.30266(15)
eS3
0.30343(18)
eS3
0.30176(15)
eS3
0.30007(19)
eS3 eS1
0.21993(19) 0.22000(17)
eS3 eS1
0.21958(16) 0.21972(15)
eS3 eS1
0.2195(2) 0.21956(18)
eS4
0.22027(18)
eS4
0.22013(15)
eS4
0.22012(19)
4
Ge
eS2
0.22456(18)
eGe eM2
0.22000(17) 0.29093(18)
eM2
0.29766(18)
eGe e2M1
0.22456(18) 0.28260(18)
eM2
0.29098(17)
eGe eM1
0.21993(19) 0.33727(18)
0.29557(15)
eM2
0.30267(15)
eM2 eGe eM2
0.22027(18) 0.28537(17)
eM2
0.29326(17)
0.22472(16)
eS2
S3
Atoms
0.22006(15)
eS4
S2
C.N.
0.21960(16) 0.21984(15)
eS1
S1
La2.64Dy1.36Ge3S12
d (nm)
0.21984(15) 0.28964(15)
3
S1
0.29668(17) 0.22472(16) 0.28146(15)
4
S2
0.29078(15) 0.21960(16) 0.28146(15)
0.22006(15) 0.28514(15) 0.29230(15)
4
3
S3
S4
4
Ge
eS2
0.22461(16)
eGe eM2
0.21972(15) 0.28889(16)
eM2
0.29613(17)
eGe e2M1
0.22461(16) 0.28199(16)
eM2
0.29044(16)
eGe eM1
0.21958(16) 0.28079(15)
0.29663(17)
eM2
0.30344(18)
eM2 eGe eM2
0.22012(19) 0.28510(15)
eM2
0.29144(15)
3
4
4
3
S1
S2
S3
S4
4
Ge
eS2
0.22466(19)
eGe eM2
0.21956(18) 0.28771(19)
eM2
0.2947(2)
eGe e2M1
0.22466(19) 0.27904(19)
eM2
0.29050(18)
eGe eM1
0.2195(2) 0.27903(19)
0.29497(15)
eM2
0.29398(18)
0.30176(15)
eM2
0.30007(19)
eGe eM2
0.22012(19) 0.28491(18)
eM2
0.28986(19)
3
4
4
3
S1
S2
S3
S4
4
3
4
4
3
Fig. 4. Unit cell and coordination polyhedra in the structure of the compounds LaхRуGe3S12 (х ¼ 2.02e2.56, y ¼ 1.36e1.98, R e Er, Ho, Dy and Tb).
system Er2S3eLa2S3eGeS2. The crystal structure of the compound, as well as the solid solutions La4e4xR4xGe3S12 (R e Tb, Dy, Ho and Er; x ¼ 0e0.75), was determined by X-ray single crystal method. Er2.34La0.66Ge1.28S7 crystallizes in the space group P63; the La4e4xR4xGe3S12 phases crystallize in the space group R3c. Atom location and coordination surrounding is demonstrated for these structures.
References [1] I.D. Olekseyuk, Quasi-potriyini Halcohenidni Systemy, Lutsk: Vezha e VDU іm. Lesia Ukrainka. Т1, 1999, p. 168. [2] Lubomir D. Gulay, Marek Daszkiewicz, Oleg V. Marchuk, Quaternary R2X3PbS-ZX2(X¼S, Se; Z¼Si, Ge, Sn) chalcogenides, in: Handbook on the Physics and Chemistry of Rare Earths, vol. 48, 2015, p. 162. [3] O.V. Smitiukh, O.V. Marchuk, I.D. Olekseyuk, L.D. Gulay, The Y2Se3‒La2Se3‒ GeS2 system at 770 K, J. Alloys Compd. 698 (2016) 739e742.
M. Daszkiewicz et al. / Journal of Alloys and Compounds 738 (2018) 263e269 [4] A.R. Landa-Canovas, U. Amador, L.C. Otero-Diaz, Erbium sulfide-Delta, J. Alloys Compd. 323 (2001) 91e96. [5] P. Basancon, C. Adolphe, J. Flahaut, P. Laruelle, Lanthanum (II) sulfide, Mater. Res. Bull. 4 (1969) 227e238. [6] G. Dittmar, H. Schaefer, Die Kristallstruktur von H.T.-GeS2, Acta Cryst. 31 (1975) 2060e2064. [7] W.H. Zachariasen, The crystal structure of germanium disulphide, J. Chem. Phys. B. 4 (1936) 618e619. [8] Z. Huiyi, Z. Fakun, G. Guocong, H. Jinshun, Syntheses and single-crystal structures of La3AgSnS7, Ln3MxMS7 (Ln ¼ La, Ho, Er; M¼ Ge, Sn; 1/4<¼ x<¼ 1/2), J. Alloys Compd. 458 (2008) 123e129. [9] A. Mazurier, J. Etienne, Structure crystalline de LaGeS5, Acta Cryst. B 29 (1973)
269
817e821. [10] Tien Vo Van, P. Khodadad, Syntheses, structure, magnetism, and optical properties of the ordered mixed-lanthanide sulfides gamma-LnLn'S3 (Ln ¼ La, Ce; Ln' ¼ Er, Tm, Yb), Bull. Soc. Chim. France 10 (1971) 3454e3458. [11] N. Rodier, V. Tien, M. Guittard, Sulfures mixtes du type CeYb3S6 formes par deux elements IIIA (scandium, yttrium et lanthanides), Mater. Res. Bull. 11 (1976) 1209e1218. [12] L.G. Akselrud, P.Yu. Zavalii, Yu. Grin, et al., WinCSD: software package for crystallographic calculations (Version 4), J. Appl. Cryst 47 (2014) 803e805. [13] G.M. Sheldrick, A Short History of SHELX Acta Crystallogr A64, 2008, p. 112. [14] A.L. Spek, PLATON: a Multipurpose Crystallographic Tool, Utrecht University, Utrecht, the Netherlands, 2007.
Contents lists available at ScienceDirect
Journal of Alloys and Compounds journal homepage: http://www.elsevier.com/locate/jalcom
The crystal structure of Er2.34La0.66Ge1.28S7 and the LaxRyGe3S12 phases (R e Tb, Dy, Ho and Er) M. Daszkiewicz a, O.V. Smitiukh b, O.V. Marchuk b, *, L.D. Gulay c a
Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P. O. Box 1410, 50-950 Wrocław, Poland Department of Inorganic and Physical Chemistry, Eastern European National University, Voli Ave 13, 43025 Lutsk, Ukraine c Department of Ecology and Protection of Environment, Eastern European National University, Voli Ave 13, 43025 Lutsk, Ukraine b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 17 October 2017 Received in revised form 8 December 2017 Accepted 19 December 2017 Available online 20 December 2017
Isothermal section of the Er2S3eLa2S3eGeS2 system at 770 K was investigated. The phase boundaries of the solid solution La4e4xR4xGe3S12 (x ¼ 0e0.75, R e Tb, Dy, Ho and Er) were determined, and their structure was investigated by single crystal and powder X-ray diffraction. The existence of new quaternary compound Er2.34La0.66Ge1.28S7 was established and its crystal structure was determined by X-ray single crystal diffraction (space group Р63, Pearson symbol hР24e1.44, a ¼ 0.96934(3) nm, c ¼ 0.58680(2) nm, R1 ¼ 0.0220). © 2017 Elsevier B.V. All rights reserved.
Keywords: Chalcogenides Rare earth compounds Crystal structure X-ray powder diffraction
1. Introduction The development of modern inorganic chemistry and semiconductor material science is associated with the design of new materials that would possess pre-set functional properties. One approach to find new substances with semiconductor properties is to study the interaction of the components of complex chalcogenide systems [1]. The study of the composition-structure-property relationship of a substance as well as the determination of its thermodynamic conditions of existence is one of the tasks of physico-chemical analysis. The information about the crystalline structure of a compound not only provides some data on interatomic distances and the coordination surrounding of atoms but also makes possible certain assumptions and conclusions about the mechanisms of chemical transformations and predictions on the synthesis of new substances. The crystal structure is one of the fundamental characteristics of a compound that determines a range of its physicochemical properties. The accumulation of experimental data on the conditions for the
* Corresponding author. E-mail address: [email protected] (O.V. Marchuk). https://doi.org/10.1016/j.jallcom.2017.12.207 0925-8388/© 2017 Elsevier B.V. All rights reserved.
formation and existence of compounds makes the process of designing new materials on their basis more purposeful [2]. Presented work is one of the stages of the systematic study of the interaction of components in complex sulfide systems R2S3eR'2S3eDIVS2 (DIV e Si, Ge, Sn; R e Lanthanide) and of determination of the crystal structure of the compounds formed therein [3]. Principal crystallographic characteristics of the binary and of the ternary components of the quasi-quaternary system Er2S3eLa2S3eGeS2 are shown in Table 1. 2. Experimental details A total of 63 samples were synthesized for the investigation of the system. The samples for the studies were prepared of the individual components of semiconductor purity. The alloys were synthesized in evacuated quartz containers in an MP-30 programmable electrical muffle furnace by heating to 1423 К at a rate of 12 К/h; exposure at 1423 К for 4 h; cooling to 770 К at a rate of 12 К/h; homogenizing and annealing at 770 К for 240 h; and finally quenching into cold water. Powder XRD patterns to determine the phase composition of synthesized alloys were recorded at a DRON 4-13 diffractometer in the range 2Q ¼ 10e80 (CuKa radiation, scan step 0.05 , 4 s exposure at each point). The data were processes using WinCSD
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Table 1 Crystallographic characteristics of the binary and of the ternary components of the quasi-quaternary system Er2S3eLa2S3eGeS2. Compound
Er2S3 La2S3 GeS2 GeS2 Er3Ge1.33S7 La2GeS5 La3Ge1.25S7 La4Ge3S12 ErLaS3 Er3LaS6
Space group
P21/m Pnma P21/с Fdd2 Р63 P21/с Р63 R3c Pnma P21/m
Lattice parameters, nm
Ref.
a
b
c
1.0072 0.766 0.6720 1,68 1.02970 0.7641 1.0297 1.940 1.6510 1.095
0.3976 b ¼ 98.66 0.422 1.6101 b ¼ 90.88 2238 e 1.2702 b ¼ 101.39 e e 0.3996 1.126 b ¼ 108.6
1.7389 0.1595 1.1436 0,687 0.58120 0.7893 0.58120 0.810 2.12597 0.398
[4] [5] [6] [7] [8] [9] [8] [9] [10] [11]
software package [12]. The investigation of the crystal structure of the quaternary phases was performed using X-ray single crystal diffraction. The Xray intensities data were collected on a Oxford Diffraction X'calibur four-circle single-crystal X-ray diffractometer with CCD Atlas detector, using graphite-monochromatized MoKa radiation (l ¼ 0.071073 nm). The raw data were treated with the CrysAlis Data Reduction program taking into account an absorption correction. The intensities of the reflections were corrected for Lorentz and polarization factors. The crystal structure was solved by Patterson methods and refined by the full-matrix least-squares method using SHELXL-2014 [13]. Acentric space groups were checked with the PLATON program, and no additional symmetry elements were found [14]. 3. Results and discussion Literature sources report the existence of GeS2 in two modifications, with the phase transition temperature of 770 K. We have identified at the annealing temperature the monoclinic modification of GeS2 (P21/с). The investigation of the quasi-quasiternary system Er2S3eLa2S3eGeS2 confirms the existence of three ternary compounds, La4Ge3S12 (space group R3c, own structure type),
Fig. 1. Isothermal section of the quasi-ternary system Er2S3eLa2S3eGeS2 at 770 K.
Table 2 Crystallographic data and structure refinement details for the Er2.34La0.66Ge1.28S7 compound. Empirical formula Formula weight Space group Unit cell dimensions: a (nm) c (nm) V (nm3) Number of formula units per unit cell Calculated density Absorption coefficient F(000) Crystal color Crystal size Q range for data collection Index ranges
Reflections collected Independent reflections Refinement method Absolute structure parameter Data/restraints/parameters Goodness-of-fit on F2 Final R indices [I>2s(I)] R indices (all data) Extinction coefficient Largest diff. peak and hole 103
Er2.34La0.66Ge1.28S7 800.45 P63 (No 173) 0.96934(3) 0.58680(2) 0.47749(3) 2 5.572 28.754 700 black 0.055 0.029 0.024 mm 2.426e26.702 12 h 12 12 h 12 7 l 7 7908 686 [R(int.) ¼ 0.0490] Full-matrix least-square on F2 0.35(2) 686/1/40 1.062 R1 ¼ 0.0220 wR2 ¼ 0.0448 R1 ¼ 0.0229 wR2 ¼ 0.0450 e 0.683 and 0.974 e/nm3
La2GeS5 (space group P21/c, own structure type), La3Ge1.25S7 (space group P63, structure type Dy3Ge1.25S7). No ternary compounds were observed in the Er2S3eGeS2 section. A part of the isothermal section of the Er2S3eLa2S3eGeS2 system at 770 K is presented in Fig. 1. A ternary phase Er3Ge1.33S7 was reported in Ref. [8] in the EreGeeS system outside the Er2S3eGeS2 section. We synthesized and annealed nine alloys of the composition Er3exLaxGe1.25S7 (x ¼ 0e0.7) and tested their phase composition. The synthesis of samples was according to the procedure described in the Experimental section. The formation of new quaternary compound of approximate composition Er2.4La0.6Ge1.25S7 was observed. A single crystal from the Er2.4La0.6Ge1.25S7 sample was selected to study its crystalline structure. Performed investigation determined the composition of the new quaternary phase as Er2.34La0.66Ge1.28S7 (structure type Dy3Ge1.25S7, space group P63, Pearson symbol hР24e1.44). Crystallographic data and structure refinement details for the Er2.34La0.66Ge1.28S7 compound are given in Table 2. Atomic coordinates and thermal displacement parameters are given in Table 3, and the interatomic distances are listed in Table 4. The position M of the mixture of randomly distributed La and Er atoms in the Er2.34La0.66Ge1.28S7 structure corresponds to the position of Dy in the structure of Dy3Ge1.25S7. The positions of Ge and S are the same in both structures. The unit cell projection and the coordination environment of atoms in the structure of the compound Er2.34La0.66Ge1.28S7 are depicted in Fig. 2. The atoms of the statistical mixture M (ErþLa) occupy the 6c site and are located in monocapped trigonal prisms with coordination number (6 þ 1). The Ge atoms are located in sites 2b and 2a which have octahedral and tetrahedral surrounding of sulfur atoms respectively. Sulfur atoms (6c and 2b sites) are coordinated by tetrahedra of cations. The existence at 770 K of the solid solution range of La4Ge3S12 (space group R3c, Pearson symbol hR38) was found in the quasiternary system Er2S3eLa2S3eGeS2; its extent is La4e4xEr4xGe3S12 (x ¼ 0e0.63). Additionally, we studied the extent of solid solutions in the
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265
Table 3 Atomic coordinates and thermal displacement parameters for the Er2.34La0.66Ge1.28S7 compound. Atom
Site
x/a
y/b
z/c
Ueq 102, nm2
U11
U22
U33
U23
U13
U12
M* Ge1 *Ge2 S1 S2 S3
6c 2b 2a 6c 6c 2b
0.21319(7) 1/3 0 0.2533(5) 0.4747(5) 1/3
0.35880(7) 2/3 0 0.1053(4) 0.5693(5) 2/3
0.5443(2) 0.1199(3) 0.2296(13) 0.4911(7) 0.2778(5) 0.7475(10)
0.0254(2) 0.0138(7) 0.009(3) 0.0288(12) 0.0197(9) 0.0168(14)
0.0185(3) 0.0170(10) 0.006(3) 0.0229(19) 0.023(2) 0.019(2)
0.0168(4) 0.0170(10) 0.006(3) 0.0176(18) 0.032(2) 0.019(2)
0.0391(4) 0.0073(10) 0.015(6) 0.045(3) 0.0122(15) 0.012(3)
0.0002(5) 0 0 0.0018(2) 0.0034(18) 0
0.0029(5) 0 0 0.0145(17) 0.0031(17) 0
0.0075(3) 0.0085(5) 0.0032(15) 0.0098(15) 0.0194(19) 0.0096(11)
*M e 0.78(3) Er þ 0.22(3) La. *Ge2 e 0.285(10) Ge. Ueq. is defined as one third of the trace of the orthogonalized Uij tensor. The anisotropic temperature factor exponent takes the form: 2p2[h2a*2U11 þ … þ 2hka*b*U12].
Table 4 Interatomic distances (d) and coordination numbers (C.N.) of atoms in the structure of the compound Er2.34La0.66Ge1.28S7. Atoms M
Ge1 Ge2 S1
S2
S3
e e e e e e e e e e e e e e e e e e e e
S1 S1 S1 S2 S3 S2 S2 S3 3S2 3S1 3S1 Ge2 M M M Ge1 M 2M Ge1 3M
d (nm)
C.N.
0.2692(4) 0.2737(4) 0.2770(4) 0.2804(4) 0.2865(3) 0.2868(4) 0.3067(4) 02186(6) 0.2218(4) 0.2554(6) 0.2631(6) 0.2554(6) 0.2737(4) 0.2770(4) 0.3367(4) 0.2288(4) 0.2868(4) 0.3067(4) 0.2186(6) 0.2865(3)
7
4 6 4
4
4
related systems La4Ge3S12e“R4Ge3S12” (R e Tb, Dy and Ho). The maximum range is observed in the La4Ge3S12e“Tb4Ge3S12” system. The change of the cell parameters within the La4e4xR4xGe3S12 solid solution ranges (R e Tb, Dy, Ho and Er) is plotted in Fig. 3. The variation in the maximum content of Tb, Dy, Ho and Er components in a solid solution range of La4Ge3S12 is associated with an reduction in the atomic radii of the elements; rare-earth cations with the closest to La3þ radius are most likely to substitute La atoms. The crystal structure of the La4e4xR4xGe3S12 solid solution (R e Tb, Dy, Ho and Er) was investigated using X-ray single crystal diffraction. Single crystals for the investigation were selected from the samples with the compositions La2R2Ge3S12 (R e Tb, Dy, Ho and Er). Results of the crystal structure determination of La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12 are presented in Table 5, where the atomic coordinates and thermal displacement parameters are given in Table 6 and interatomic distances are collected in Table 7. Two mixtures of the randomly distributed R and La atoms (M1 and M2) exist for all structures. Obtained data agree well with reported in Ref. [2] results for La4e4xY4xGe3S12 (x ¼ 0) solid solution. Unit cell projection and the coordination environment of atoms in the structure of the quaternary phases La4e4xR4xGe3S12 (R e Tb,
Fig. 2. Unit cell and coordination polyhedra in the structure of the compound Er2.34La0.66Ge1.28S7.
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Fig. 3. Variation of the rhombohedral cell parameters within the solid solution ranges La4e4xR4xGe3S12: а) R ¼ Tb (x ¼ 0e0.72); b) R ¼ Dy (x ¼ 0e0.70); c) R ¼ Ho (x ¼ 0e0.60); d) R ¼ Er (x ¼ 0e0.63).
Dy, Ho and Er) are shown in Fig. 4. The M1 (6a site) and M2 (18b site) atoms are located in trigonal and bi-capped trigonal prisms respectively. The Ge atoms (18b site) have a tetrahedral surrounding of sulfur atoms. The S1 and S4 atoms are surrounded by three atoms. Both S2 and S3 atoms are located in tetrahedra. Mixed M1 site prefers the small R cation and the M2 site prefers the large La
cation, similar to the La:Y analog. 4. Conclusion A new quaternary compound Er2.34La0.66Ge1.28S7 was found in the investigation of the isothermal section of the quasi-ternary
Table 5 Results of the crystal structure determination of La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12. Empirical formula
La2.02Tb1.98Ge3S12
La2.64Dy1.36Ge3S12
La2.25Ho1.75Ge3S12
La2.16Er1.84Ge3S12
Space group Formula weight Unit cell dimensions: a (nm) c (nm) V (nm3) Number of formula units per unit cell Calculated density Absorption coefficient F(000) Crystal color Crystal size Q range for data collection Index ranges
R3c (No 161) 1197.84
R3c (No 161) 1190.21
R3c (No 161) 1203.77
R3c (No 161) 1210.39
1.92627(5) 0.79263(2) 2.54705(16) 6 4.685 19.781 3191 yellow 0.162 0.128 0.103 mm 3.664e28.275 25 h 23 25 k 25 10 l 10 7177 1372 [R(int.) ¼ 0.0229] Full-matrix least-square on F2 0.018(10) 1372/1/60 1.090 R1 ¼ 0.0141 wR2 ¼ 0.0290 R1 ¼ 0.0151 wR2 ¼ 0.0293 e 0.429 and 0.710 e/nm3
1.92868(5) 0.79498(2) 2.56099(14) 6 4.630 18.978 3169 yellow 0.192 0.106 0.052 mm 3.660e27.450 24 h 21 23 k 24 10 l 10 6175 1287 [R(int.) ¼ 0.0490]
1.92448(6) 0.79096(4) 2.5370(2) 6 4.727 20.360 3201 black 0.301 0.078 0.071 mm 3.668e27.470 24 h 24 24 k 24 9 l 10 5780 1263 [R(int.) ¼ 0.0214]
1.92165(4) 0.78757(2) 2.51866(13) 6 4.788 21.228 3218 yellow 0.374 0.074 0.039 mm 3.673e27.473 24 h 23 24 k 24 10 l 10 7267 1270 [R(int.) ¼ 0.0255]
0.005(9) 1287/1/60 1.128 R1 ¼ 0.0151 wR2 ¼ 0.0296 R1 ¼ 0.0158 wR2 ¼ 0.0298 e 0.478 and 0.830 e/nm3
0.015(8) 1263/1/60 1.072 R1 ¼ 0.0133 wR2 ¼ 0.0258 R1 ¼ 0.0140 wR2 ¼ 0.0259 e 0.350 and 0.481 e/nm3
0.027(10) 1270/1/60 1.122 R1 ¼ 0.0155 wR2 ¼ 0.0360 R1 ¼ 0.0159 wR2 ¼ 0.0362 e 0.492 and 0.959 e/nm3
Reflections collected Independent reflections Refinement method Absolute structure parameter Data/restraints/parameters Goodness-of-fit on F2 Final R indices [I>2s(I)] R indices (all data) Extinction coefficient Largest diff. peak and hole 103
Table 6 Atomic coordinates and thermal displacement parameters for La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12. Atom
Site
z/c
Ueq 102, nm2
U11
U22
U33
U23
U13
U12
0 0.23214(2) 0.18612(3) 0.17791(9) 0.05962(9) 0.20154(9) 0.27040(9) þ 0.867(18) Tb; þ 0.371(14) Tb.
0 0.00481(2) 0.19854(3) 0.28680(8) 0.12026(9) 0.11378(9) 0.27465(9)
0.00000(6) 0.29107(5) 0.34133(7) 0.50334(19) 0.2509(2) 0.50011(19) 0.14436(18)
0.01507(16) 0.01602(10) 0.01108(17) 0.0181(3) 0.0156(3) 0.0162(3) 0.0171(3)
0.0172(2) 0.01492(17) 0.0106(3) 0.0213(8) 0.0129(7) 0.0249(9) 0.0124(7)
0.0172(2) 0.01895(18) 0.0098(3) 0.0120(7) 0.0119(7) 0.0154(7) 0.0199(8)
0.0108(2) 0.01843(17) 0.0132(3) 0.0217(8) 0.0205(8) 0.0151(7) 0.0175(7)
0 0.00704(1) 0.0013(2) 0.0011(6) 0.0007(6) 0.0002(5) 0.0063(6)
0 0.00681(1) 0.0021(2) 0.0056(6) 0.0017(5) 0.0015(6) 0.0045(6)
0.00862(10) 0.01165(14) 0.0053(3) 0.0088(6) 0.0051(6) 0.0150(7) 0.0070(6)
0 0.23180(2) 0.18617(4) 0.17763(11) 0.06020(10) 0.20135(11) 0.27045(10) þ 0.649(17) Dy; þ 0.237(12) Dy.
0 0.00440(2) 0.19870(4) 0.28681(10) 0.12063(10) 0.11384(10) 0.27455(11)
0.00002(6) 0.29217(5) 0.34239(8) 0.5037(2) 0.2507(2) 0.5012(2) 0.1456(2)
0.01332(19) 0.01431(11) 0.01012(19) 0.0167(4) 0.0143(4) 0.0153(4) 0.0154(4)
0.0160(2) 0.0139(2) 0.0101(4) 0.0206(9) 0.0113(8) 0.0243(10) 0.0121(9)
0.0160(2) 0.0174(2) 0.0093(4) 0.0120(8) 0.0125(8) 0.0145(8) 0.0180(9)
0.0080(3) 0.01537(18) 0.0111(3) 0.0181(9) 0.0190(9) 0.0126(8) 0.0147(8)
0 0.00652(2) 0.0011(3) 0.0003(7) 0.0014(7) 0.0012(7) 0.0062(7)
0 0.00619(2) 0.0019(3) 0.0054(7) 0.0012(7) 0.0013(7) 0.0038(7)
0.00800(12) 0.01061(18) 0.0049(3) 0.0085(7) 0.0058(7) 0.0139(8) 0.0066(7)
0 0.23235(2) 0.18600(4) 0.17798(10) 0.05927(9) 0.20170(10) 0.27032(9) þ 0.784(16) Ho; þ 0.323(11) Ho.
0 0.00512(2) 0.19840(3) 0.28676(9) 0.12012(9) 0.11377(9) 0.27474(10)
0.00000(5) 0.29028(4) 0.34061(7) 0.50298(19) 0.2511(2) 0.49982(18) 0.14319(18)
0.01514(17) 0.01557(10) 0.01083(17) 0.0188(4) 0.0156(3) 0.0164(3) 0.0171(4)
0.0179(2) 0.01454(18) 0.0107(3) 0.0224(8) 0.0120(7) 0.0255(9) 0.0137(8)
0.0179(2) 0.01920(19) 0.0097(3) 0.0124(7) 0.0132(7) 0.0159(8 0.0206(8)
0.0095(2) 0.01722(15) 0.0124(3) 0.0223(8) 0.0208(7) 0.0140(7) 0.0161(7)
0 0.00705(13) 0.0014(2) 0.0007(6) 0.0004(6) 0.0012(6) 0.0077(6)
0 0.00671(13) 0.0025(2) 0.0069(6) 0.0022(6) 0.0015(6) 0.0057(6)
0.00897(11) 0.01162(15) 0.0053(3) 0.0091(7) 0.0058(6) 0.0152(7) 0.0078(7)
0 0.23269(2) 0.18583(4) 0.17814(12) 0.05862(10) 0.20200(11) 0.27028(11) þ 0.800(18) Er; þ 0.348(13) Er.
0 0.00561(2) 0.19819(4) 0.28665(10) 0.11948(11) 0.11378(11) 0.27482(11)
0.00000(7) 0.28909(5) 0.3395(9) 0.5030(3) 0.2514(3) 0.4996(2) 0.1414(2)
0.0156(2) 0.01575(13) 0.0106(2) 0.0197(4) 0.0156(4) 0.0159(4) 0.0174(4)
0.0184(2) 0.0142(2) 0.0104(4) 0.0227(9) 0.0115(8) 0.0235(10) 0.0140(9)
0.0184(2) 0.0196(2) 0.0090(3) 0.0119(8) 0.0121(8) 0.0149(8) 0.0207(9)
0.0099(3) 0.0176(2) 0.0130(3) 0.0248(10) 0.0218(9) 0.0154(8) 0.0178(9)
0 0.00745(15) 0.0016(3) 0.0011(7) 0.0001(7) 0.0015(7) 0.0079(7)
0 0.00701(15) 0.0029(3) 0.0090(7) 0.0022(7) 0.0024(7) 0.0064(7)
0.00921(12) 0.01162(16) 0.0052(3) 0.0088(7) 0.0048(7) 0.0143(7) 0.0088(7)
M. Daszkiewicz et al. / Journal of Alloys and Compounds 738 (2018) 263e269
La2.02Tb1.98Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.133(18) La M2* e 0.629(14) La La2.64Dy1.36Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.351(17) La M2* e 0.763(12) La La2.25Ho1.75Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.216(16) La M2* e 0.677(11) La La2.16Er1.84Ge3S12 M1* 6a M2* 18b Ge 18b S1 18b S2 18b S3 18b S4 18b M1* e 0.200(18) La M2* e 0.652(13) La
y/b
x/a
Ueq. is defined as one third of the trace of the orthogonalized Uij tensor. The anisotropic temperature factor exponent takes the form: 2p2[h2a*2U11 þ … þ 2hka*b*U12].
267
268
M. Daszkiewicz et al. / Journal of Alloys and Compounds 738 (2018) 263e269
Table 7 Interatomic distances (d) and coordination numbers (C.N.) of atoms in the structures of La2.02Tb1.98Ge3S12, La2.64Dy1.36Ge3S12, La2.25Ho1.75Ge3S12 and La2.16Er1.84Ge3S12. La2.02Tb1.98Ge3S12 Atoms M1*
e3S2 e3S2
M2*
eS4 eS1 eS4 eS2 eS3 eS1 eS3
Ge
eS3
eGe eM2 eM2 eGe e2M1 eM2 eGe eM1 eM2 eM2
S4
0.28146(15) 0.28250(16)
6
M1*
0.28515(15) 0.28964(15)
7
M2*
eGe eM2 eM2
La2.25Ho1.75Ge3S12
d (nm)
C.N.
Atoms
e3S2 e3S2
0.28260(18) 0.28342(18)
6
M1*
eS4 eS1
0.28539(17) 0.29093(18)
7
M2*
0.29079(15)
eS4
0.29230(15) 0.29557(15)
La2.16Er1.84Ge3S12
d (nm)
C.N.
Atoms
d (nm)
C.N.
e3S2 e3S2
0.28080(15) 0.28200(16)
6
M1*
e3S2 e3S2
0.27904(19) 0.2806(2)
6
eS4 eS1
0.28512(15) 0.28888(16)
7
M2*
eS4 eS1
0.28491(18) 0.28770(19)
7
0.29098(17)
eS4
0.29044(16)
eS4
0.28986(19)
eS2
0.29326(17)
eS2
0.29145(15)
eS2
0.29050(18)
eS3
0.29663(17)
eS3
0.29497(15)
eS3
0.29398(18)
0.29668(17)
eS1
0.29766(18)
eS1
0.29614(17)
eS1
0.2947(2)
0.30266(15)
eS3
0.30343(18)
eS3
0.30176(15)
eS3
0.30007(19)
eS3 eS1
0.21993(19) 0.22000(17)
eS3 eS1
0.21958(16) 0.21972(15)
eS3 eS1
0.2195(2) 0.21956(18)
eS4
0.22027(18)
eS4
0.22013(15)
eS4
0.22012(19)
4
Ge
eS2
0.22456(18)
eGe eM2
0.22000(17) 0.29093(18)
eM2
0.29766(18)
eGe e2M1
0.22456(18) 0.28260(18)
eM2
0.29098(17)
eGe eM1
0.21993(19) 0.33727(18)
0.29557(15)
eM2
0.30267(15)
eM2 eGe eM2
0.22027(18) 0.28537(17)
eM2
0.29326(17)
0.22472(16)
eS2
S3
Atoms
0.22006(15)
eS4
S2
C.N.
0.21960(16) 0.21984(15)
eS1
S1
La2.64Dy1.36Ge3S12
d (nm)
0.21984(15) 0.28964(15)
3
S1
0.29668(17) 0.22472(16) 0.28146(15)
4
S2
0.29078(15) 0.21960(16) 0.28146(15)
0.22006(15) 0.28514(15) 0.29230(15)
4
3
S3
S4
4
Ge
eS2
0.22461(16)
eGe eM2
0.21972(15) 0.28889(16)
eM2
0.29613(17)
eGe e2M1
0.22461(16) 0.28199(16)
eM2
0.29044(16)
eGe eM1
0.21958(16) 0.28079(15)
0.29663(17)
eM2
0.30344(18)
eM2 eGe eM2
0.22012(19) 0.28510(15)
eM2
0.29144(15)
3
4
4
3
S1
S2
S3
S4
4
Ge
eS2
0.22466(19)
eGe eM2
0.21956(18) 0.28771(19)
eM2
0.2947(2)
eGe e2M1
0.22466(19) 0.27904(19)
eM2
0.29050(18)
eGe eM1
0.2195(2) 0.27903(19)
0.29497(15)
eM2
0.29398(18)
0.30176(15)
eM2
0.30007(19)
eGe eM2
0.22012(19) 0.28491(18)
eM2
0.28986(19)
3
4
4
3
S1
S2
S3
S4
4
3
4
4
3
Fig. 4. Unit cell and coordination polyhedra in the structure of the compounds LaхRуGe3S12 (х ¼ 2.02e2.56, y ¼ 1.36e1.98, R e Er, Ho, Dy and Tb).
system Er2S3eLa2S3eGeS2. The crystal structure of the compound, as well as the solid solutions La4e4xR4xGe3S12 (R e Tb, Dy, Ho and Er; x ¼ 0e0.75), was determined by X-ray single crystal method. Er2.34La0.66Ge1.28S7 crystallizes in the space group P63; the La4e4xR4xGe3S12 phases crystallize in the space group R3c. Atom location and coordination surrounding is demonstrated for these structures.
References [1] I.D. Olekseyuk, Quasi-potriyini Halcohenidni Systemy, Lutsk: Vezha e VDU іm. Lesia Ukrainka. Т1, 1999, p. 168. [2] Lubomir D. Gulay, Marek Daszkiewicz, Oleg V. Marchuk, Quaternary R2X3PbS-ZX2(X¼S, Se; Z¼Si, Ge, Sn) chalcogenides, in: Handbook on the Physics and Chemistry of Rare Earths, vol. 48, 2015, p. 162. [3] O.V. Smitiukh, O.V. Marchuk, I.D. Olekseyuk, L.D. Gulay, The Y2Se3‒La2Se3‒ GeS2 system at 770 K, J. Alloys Compd. 698 (2016) 739e742.
M. Daszkiewicz et al. / Journal of Alloys and Compounds 738 (2018) 263e269 [4] A.R. Landa-Canovas, U. Amador, L.C. Otero-Diaz, Erbium sulfide-Delta, J. Alloys Compd. 323 (2001) 91e96. [5] P. Basancon, C. Adolphe, J. Flahaut, P. Laruelle, Lanthanum (II) sulfide, Mater. Res. Bull. 4 (1969) 227e238. [6] G. Dittmar, H. Schaefer, Die Kristallstruktur von H.T.-GeS2, Acta Cryst. 31 (1975) 2060e2064. [7] W.H. Zachariasen, The crystal structure of germanium disulphide, J. Chem. Phys. B. 4 (1936) 618e619. [8] Z. Huiyi, Z. Fakun, G. Guocong, H. Jinshun, Syntheses and single-crystal structures of La3AgSnS7, Ln3MxMS7 (Ln ¼ La, Ho, Er; M¼ Ge, Sn; 1/4<¼ x<¼ 1/2), J. Alloys Compd. 458 (2008) 123e129. [9] A. Mazurier, J. Etienne, Structure crystalline de LaGeS5, Acta Cryst. B 29 (1973)
269
817e821. [10] Tien Vo Van, P. Khodadad, Syntheses, structure, magnetism, and optical properties of the ordered mixed-lanthanide sulfides gamma-LnLn'S3 (Ln ¼ La, Ce; Ln' ¼ Er, Tm, Yb), Bull. Soc. Chim. France 10 (1971) 3454e3458. [11] N. Rodier, V. Tien, M. Guittard, Sulfures mixtes du type CeYb3S6 formes par deux elements IIIA (scandium, yttrium et lanthanides), Mater. Res. Bull. 11 (1976) 1209e1218. [12] L.G. Akselrud, P.Yu. Zavalii, Yu. Grin, et al., WinCSD: software package for crystallographic calculations (Version 4), J. Appl. Cryst 47 (2014) 803e805. [13] G.M. Sheldrick, A Short History of SHELX Acta Crystallogr A64, 2008, p. 112. [14] A.L. Spek, PLATON: a Multipurpose Crystallographic Tool, Utrecht University, Utrecht, the Netherlands, 2007.