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Trimeric Units [Ag 3 X 8 ] 5– with Face‐sharing Polyhedra in the Series Tl 2 Ag X 3 ( X = Cl, Br, I): Synthesis, Crystal Structure, and Vibrational Spectra
Author(s) -
Hillebrecht Harald,
Ade Martin
Publication year - 2018
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700358
Subject(s) - isostructural , octahedron , crystallography , ternary operation , ampoule , crystal structure , halide , hydrothermal circulation , materials science , chemistry , analytical chemistry (journal) , inorganic chemistry , seismology , computer science , programming language , geology , chromatography
The ternary compounds Tl 2 Ag X 3 ( X = Cl, Br, I) were obtained as colorless single crystals by reaction of the binary halides Ag X and Tl X ( X = Cl, Br, I) together with concentrated H X solutions under hydrothermal conditions. Silica glass ampoules were filled to 50 % with these solutions and heated for several days up to 250 °C. The reaction was carried out in steel autoclaves to prevent bursting. All the compounds are isostructural and crystallize trigonally with the already known Tl 2 AgI 3 type ( R 3 , Z = 9), but Tl 2 AgCl 3 [ a = 9.5075(6), c = 18.585(2) Å, R 1 = 0.035, wR 2 = 0.062] and Tl 2 AgBr 3 [ a = 9.8758(6), c = 19.1532(14) Å, R 1 = 0.046, wR 2 = 0.085] were characterized for the first time. The crystal structure consists of unique [Ag 3 X 8 ] 5– units, which are formed by a central [Ag X 6 ] 5– octahedron with two face‐sharing [Ag X 4 ] 4– tetrahedra in trans position. The Ag + ··· Ag + distance is nearly independent from the anion size and amounts to 3.13–3.16 Å. The distance results just from repulsive interactions. Vibrational spectra were recorded for the complete series. DTA measurements confirm the peritectic formation of both compounds with X = Cl and Br.