K6Tl2Sb3, A Zintl Phase with a Novel Heteroatomic [Tl4Sb612-] Chain1
journal contributionposted on 20.04.2001, 00:00 by Lisheng Chi, John D. Corbett
The title compound with heteratomic anionic chains [Tl4Sb612-] has been discovered in the K−Tl−Sb system. The phase is obtained from a range of compositions near K3TlSb1.5 following reaction first at 750−850 °C and then at 550 °C for one week or more. It crystallizes in the monoclinic system in space group C2/c, Z = 8, a = 9.951(1) Å, b = 17.137(3) Å, c = 19.640(6) Å, and β = 104.26(3)°. Swing-like (Tl4Sb6)12- units consisting of alternating Sb and Tl atoms in four- and eight-membered rings are linked through Tl−Tl bonds to form infinite one-dimensional chains along a⃗. EHTB calculations and resistivity measurements show that the compound is a semiconductor.