Abstract: | The new compounds K12Ta6Se35 and KTaTe3 have been synthesized through the reaction of Ta metal with a K2Qn(Q = Se, Te) flux. K12Ta6Se35, crystallizes with 4 formula units in space group Pbcn of the orthorhombic system in a cell of dimensions a = 8.3390(17) Å, b = 13.259(3) Å, c = 56.023(11) Å (t = −120 °C). KTaTe3 crystallizes with 20 formula units (or 4 formula units of K5Ta5Te15) in the monoclinic space group P21/c in a cell of dimension a = 7.7177(15) Å, b= 13.826(3) Å, c = 30.981(6) Å, and β = 90.11(3)° (t = −120 °C). Each structure consists of infinite anionic chains of Ta-containing polyhedra well separated by K+ cations. In K12Ta6Se35 there are Ta2Se11 units formed by the face sharing of two TaSe7 elongated bipyramids. These Ta2Se11 units are in turn interconnected by Se2 and Se3 units to form α1[Ta6Se3Se3512−]infinite chains. In KTaTe3, the α1[TaTe3−] infinite chains arise from the face sharing of distorted TaTe6 octahedra. |