G. Gabl, Kurt O. Klepp,
"New Complex Sulfides of the heavy Va-Metals with Pseudo-Onedimensional Structures. Preparation and Structural Characterization of K2AgNbS4, Cs2AgNbS4, K2AgTaS4, Rb2AgTaS4 and Cs2AgTaS4"
, in European Journal of Solid State and Inorganic Chemistry, 1997, ISSN: 0992-4361, K.O. Klepp, G. Gabl: New Complex Sulfides of the heavy Va-Metals with Pseudo-Onedimensional Structures. Preparation and Structural Characterization of K2AgNbS4, Cs2AgNbS4, K2AgTaS4, Rb2AgTaS4 and Cs2AgTaS4, Eur. J. Solid Inorg. Chem., 34 (1997) 1119 - 1131
Original Titel:
New Complex Sulfides of the heavy Va-Metals with Pseudo-Onedimensional Structures. Preparation and Structural Characterization of K2AgNbS4, Cs2AgNbS4, K2AgTaS4, Rb2AgTaS4 and Cs2AgTaS4
Sprache des Titels:
Englisch
Englische Kurzfassung:
The new compounds K2AgNbS4, Cs2AgNbS4, K2AgTaS4, Rb2AgTaS4 and Cs2AgTaS4 were obtained as colourless coarse crystals by reacting stoichiometric powdered mixtures of the corresponding alkali sulfide A2S, Va-metal, Ag and S at 900?C followed by slow cooling. They crystallize in the orthorhombic system, space group Fddd, Z=8 with a=5.9130(4)Ä, b=13.201(2)Ä, c=22.645(3)Ä (K2AgNbS4); a=5.9468(8)Ä, b=14.090(4)Ä, c=24.605(4)Ä (Cs2AgNbS4); a=5.929(1)Ä, b=13.197(2)Ä, c=22.645(8)Ä (K2AgTaS4); a=5.953(1)Ä, b=13.560(3)Ä, c=23.50(1)Ä (Rb2AgTaS4); and a=5.976(1)Ä, b=14.098(6)Ä, c=24.61(1)Ä (Cs2AgTaS4). The crystal structures were determined from crystal diffractometer data (MoK alpha radiation, 294K) and refined to conventional R-values of 0.017 (K2AgNbS4) to 0.032 (K2AgTaS4).
The compounds form an isostructural series. They are characterized by linear chains alternating AgS4- and TS4 tetrahedra sharing opposite edges which in the crystal structure are arranged in a hexagonal rod packing. Nb-S and Ta-S bond lengths are in the range of 2.272Ä to 2.286Ä, Ag-S bond lengths lie within 2.543Ä and 2.559Ä. The AgS4 tetrahedra are severly distorted in the chain direction. The alkali cations are coordinated to eight sulfur atoms in an irregular configuration. The atomic arrangement corresponds to that of K2CuNbSe4.
Journal:
European Journal of Solid State and Inorganic Chemistry
Erscheinungsjahr:
1997
Notiz zum Zitat:
K.O. Klepp, G. Gabl: New Complex Sulfides of the heavy Va-Metals with Pseudo-Onedimensional Structures. Preparation and Structural Characterization of K2AgNbS4, Cs2AgNbS4, K2AgTaS4, Rb2AgTaS4 and Cs2AgTaS4, Eur. J. Solid Inorg. Chem., 34 (1997) 1119 - 1131