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Syntheses, crystal structures and spectroscopic properties of Ag{sub 2}Nb[P{sub 2}S{sub 6}][S{sub 2}] and KAg{sub 2}[PS{sub 4}]

Journal Article · · Journal of Solid State Chemistry
OSTI ID:21212216
 [1];  [1]
  1. Institut fuer Anorganische Chemie, Universitaet Kiel, Olshausenstr. 40, D-24098 Kiel (Germany)
Ag{sub 2}Nb[P{sub 2}S{sub 6}][S{sub 2}] (1) was obtained from the direct solid state reaction of Ag, Nb, P{sub 2}S{sub 5} and S at 500 deg. C. KAg{sub 2}[PS{sub 4}] (2) was prepared from the reaction of K{sub 2}S{sub 3}, Ag, Nd, P{sub 2}S{sub 5} and extra S powder at 700 deg. C. Compound 1 crystallizes in the orthorhombic space group Pnma with a=12.2188(11), b=26.3725(16), c=6.7517(4) A, V=2175.7(3) A{sup 3}, Z=8. Compound 2 crystallizes in the non-centrosymmetric tetragonal space group I4-bar2m with lattice parameters a=6.6471(7), c=8.1693(11) A, V=360.95(7) A{sup 3}, Z=2. The structure of Ag{sub 2}Nb[P{sub 2}S{sub 6}][S{sub 2}] (1) consists of [Nb{sub 2}S{sub 12}], [P{sub 2}S{sub 6}] and new found puckered [Ag{sub 2}S{sub 4}] chains which are along [001] direction. The Nb atoms are located at the center of distorted bicapped trigonal prisms. Two prisms share square face of two [S{sub 2}{sup 2-}] to form one [Nb{sub 2}S{sub 12}] unit, in which Nb-Nb bond is formed. The [Nb{sub 2}S{sub 12}] units share all S{sup 2-} corners with ethane-like [P{sub 2}S{sub 6}] units to form 14-membered rings. The novel puckered [Ag{sub 2}S{sub 4}] chains are composed of distorted [AgS{sub 4}] tetrahedra and [AgS{sub 3}] triangles that share corners with each other. These chains are connected with [P{sub 2}S{sub 6}] units and [Nb{sub 2}S{sub 12}] units to form three-dimensional frame work. The structural skeleton of 2 is built up from [AgS{sub 4}] and [PS{sub 4}] tetrahedra linked by corner-sharing. The three-dimensional anionic framework contains orthogonal, intersecting tunnels directed along [100] and [010]. This compound possesses a compressed chalcopyrite-like structure. The structure is compressed along [001] and results from eight coordination sphere for K{sup +}. Both compounds are characterized with UV/vis diffuse reflectance spectroscopy and compound 1 with IR and Raman spectra. - Graphical abstract: The thiophosphates Ag{sub 2}Nb[P{sub 2}S{sub 6}][S{sub 2}] and KAg{sub 2}[PS{sub 4}] crystallize as three-dimensional networks. A remarkable structural feature of the former compound is a [Ag{sub 2}S{sub 4}] chain composed of [AgS{sub 4}] tetrahedra and [AgS{sub 3}] triangles.
OSTI ID:
21212216
Journal Information:
Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 3 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
Country of Publication:
United States
Language:
English