Syntheses, crystal structures, and solid state NMR investigations of K4M2P6S25 and K3M2P5S18 (M=Ti, Sn)
2002; Elsevier BV; Volume: 4; Issue: 5 Linguagem: Inglês
10.1016/s1293-2558(02)01320-1
ISSN1873-3085
AutoresVolkmar Derstroff, Wolfgang Tremel, Guido Regelsky, Jörn Schmedt auf der Günne, Hellmut Eckert,
Tópico(s)Iron-based superconductors research
ResumoReaction of K2S5 with P4S10 and Ti at 450 °C results in the formation of K4Ti2P6S25, a new titanium thiophosphate, whose crystal structure was solved by single-crystal X-ray diffraction. The title compound crystallizes in the orthorhombic space group Fdd2, with the lattice constants a=33.819(7), b=35.508(7), and c=6.251(1) Å (Z=8). The structure contains a layered arrangement of crosslinked quasi-one-dimensional Ti2P6S4−25 chains. The K+ ions are situated between the layers. The Ti atoms within the chains are octahedrally coordinated by P2S4−7 and P2S4−9 ligands. Reaction of K2S with P4S10, S and Ti at 600 °C results in the formation of K3Ti2P5S18, a novel titanium thiophosphate, which crystallizes in the monoclinic space group C2/c, with a=22.739(5), b=6.058(1), c=20.440(4) Å, and β=105.41(3)° (Z=4). The structure contains linear Ti2P5S3−18 chains with the K+ ions situated between the chains. The Ti atoms within the chains are octahedrally coordinated by PS3−4 and P2S4−7 ligands. Reaction of K2S with P4S10, S and Sn at 600 °C results in the formation of the isostructural compound K3SnP5S18, a novel tin thiophosphate, with the lattice parameters a=23.303(7), b=6.023(2), c=20.888(6) Å, and β=106.18(2)°. The spectroscopic characteristics of the thiophosphate groups, in particular that of the novel P2S4−9 entity are examined by UV–VIS, FT–IR and 31P one- and two-dimensional magic-angle spinning (MAS-) NMR studies. The NMR experiments illustrate the utility of double-quantum coherence techniques as a unique tool of site assignments based on 31P–31P spatial proximity, allowing a spectroscopic distinction of the P2S4−7 and the P2S4−9 groups can be differentiated based on their different chemical shift anisotropies.
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