HYDROTHERMAL SYNTHESIS OF K2PDSE10 - COEXISTENCE OF 2 LARGE INTERPENETRATING 3-DIMENSIONAL FRAMEWORKS OF [PD(SE4)2]2- AND [PD(SE6)2]2-

The hydrothermal reaction of PdCl2 with K2Se4 in the presence of different KOH and water in the 1:5:5:40 ratio produced K2[PdSe10] (I), the first metal polychalcogenide compound containing two interpenetrating three-dimensional frameworks. The black rectangular chunky crystals of I are insoluble in water and most organic solvents. They crystallize in the orthorhombic space group I2(1)2(1)2(1) (no. 24) with a = 15.872 (9) angstrom, b = 15.922 (9) angstrom, c = 12.885 (8) angstrom, V = 3256 (6) angstrom3. I is composed of two independent interpenetrating 3D diamond-like frameworks of [Pd(Se4)2]2- and [Pd(Se6)2]2-. Each framework contains large tunnels running parallel to the a- and b-crystallographic axes. The coordination geometry around Pd is square-planar. The average Pd-Se and Se-Se distances are 2.462 (5) and 2.35 (2) angstrom, respectively. The closest distances between K+ ions and Se atoms are in the range of 3.27 (2) and 3.75 (2) angstrom.