- Rare earth metal disulfides - Syntheses and crystal structures of α-CeS2, α-NdS2, β-LaS2, β-CeS2, and β-PrS2
-
α-CeS2 and α-NdS2 were obtained by a metathesis reaction of the anhydrous trichlorides LfiCI3 (Ln = Ce, Nd) and Na2S2 at 1070 K. The two compounds adopt a monoclinic structure type, the so-called CeSe
- Schleid, Thomas,Lauxmann, Petra,Graf, Christian,Bartsch, Christian,Doert, Thomas
-
-
Read Online
- STUDIES ON LANTHANOIDS-ANTIMONY-CHALCOGENIDES. I. SYNTHESIS AND CRYSTAL DATA OF THREE NEW LANTHANUM ANTIMONY CHALCOGENIDES.
-
Three new La-Sb chalcogenides were synthesized by hydrothermal or evacuated silica tube methods. (1) LaSbO//2S//2: a bright-red needle crystal; crystal system, hexagonal; space group, P6//3/m; lattice constants, a equals 14. 954(3), c equals 3. 898(2) A, and Z equals 6. (2) La//6Sb//8S//2//1: a blackish-red columnar crystal with metallic luster, orthorhombic, P222, a equals 14. 317(2), b equals 15. 239(4), c equals 8. 685(1) A, and Z equals 2. (3) La//3Sb//3S//1//0: a bright-red plate-like crystal, monoclinic, a equals 13. 209(6), b equals 14. 229(6), c equals 5. 583(1) A, beta equals 94. 54(3) degree , and Z equals 2.
- Gao,Nakai,Nagashima
-
-
Read Online
- LaS1.9, CeS1.9, PrS1.9, NdS1.9, and GdS1.9: Five new lanthanide polysulfides - Syntheses, crystal structures and their structural relationship to the ZrSSi type
-
Crystals of the five new lanthanide polysulfides LaS1.9, CeS1.9, PrS1.9, NdS1.9, and GdS1.9 have been prepared by different synthetic routes. According to X-ray structure analyses, the compounds adopt the tetragonal CeSe1.9 type structure (space group: P42/n, no. 86) with the lattice parameters a = 9.111(1)A, c = 16.336(2) A (LaS1.9), a = 9.015(3) A, c = 16.168(4) A(CeS1.9), a = 8.947(3) A, c = 16.054(4) A (PrS1.9), a = 8.901 (3) A, c = 16.022(4) A(NdS1.9), and a = 8.714(1) A, c = 15.791(1) A (GdS1.9), respectively. The crystal structure consists of puckered [LnS] double slabs and planar sulfur layers alternating along [001]. Each planar sulfur layer contains disulfide dumbbells, isolated anions and ordered vacancies.
- Doert, Thomas,Graf, Christian,Lauxmann, Petra,Schleid, Thomas
-
-
Read Online
- The La2S3LaS2 system: Thermodynamic and kinetic study
-
A detailed thermodynamic study of the LaS2La2S 3 system in the temperature range 3501000 °C was performed, starting from high quality crystals LaS2 as the highest polysulfide in the system, and using a sensitive static tensimetric method with a quartz Bourdon gauge and a membrane as a null-point instrument. The pSTx diagram obtained has shown that the phase region covering the composition between LaS2 and La2S3, which was previously described as a single grossly nonstoichiometric phase, consists of three discrete stoichiometric phases, LaS2.00, LaS1.91, and LaS1.76, where compositions could be determined with an accuracy of ±0.01 f.u. The thermodynamic characteristics of evaporation of the polysulfides as well as standard heat of LaS2 formation were calculated. The role of kinetics in the formation of ordered superstructures of sulfur-poorer polysulfides with different formal concentration of vacancies is considered.
- Vasilyeva,Nikolaev
-
-
Read Online