Publikationsdatum:
2011-12-24
Beschreibung:
From solid state reactions of Ag 2 O, HgO, and Sb 2 O 3 at high temperatures under elevated oxygen pressures a new silver mercury antimonate, Ag 5 HgSbO 6 , has been obtained. According to a single crystal structure determination Ag 5 HgSbO 6 crystallizes in space group P 1 c (no. 163) with a = 5.9263(4), c = 12.3023(7) Å, V = 374.18(4) Å 3 , Z = 2, 498 independent reflections, R 1 = 0.030, wR 2 = 0.059 ( I ≥ 2 σ ( I ). Ag 5 HgSbO 6 consists of HgSbO 6 layers, analogous to BiI 3, which are separated by Kagome nets formed by Ag + ions. Perpendicular to these layers and along the c axis linear strings of Ag + ions run through the large voids of the layers. Accordingly, Ag 5 HgSbO 6 adopts the Ag 5 Pb 2 O 6 type of structure where the lead positions are occupied by mercury and antimony alternatingly. The finding of mercury in octahedral coordination, particularly besides the lower charged Ag + cations in linear coordination, which is also highly preferred by Hg 2+ ions, is rather unexpected. Ag 5 HgSbO 6 starts to decompose at 450 °C and, in contrast to subvalent and metallic Ag 5 Pb 2 O 6 , the new compound is charge balanced and semiconducting ( ρ = 5.7 Ωcm at ambient temperature, E a = 0.047 eV).
Print ISSN:
0044-2313
Digitale ISSN:
1521-3749
Thema:
Chemie und Pharmazie
