A copper germanate containing potassium in its two-dimensional channel network

Single crystals of the new copper(II) germanate K2Cu3Ge5O14 have been grown . Conditions for the synthesis are reported. The crystal structure of this material has been established by single-crystal X-ray diffraction: triclini c, space group P (1) over bar a = 6.1859(4) Angstrom, b = 7.1484(5) Angstro m, c = 7.8491(5) Angstrom, alpha = 82.150(1)degrees, beta = 72.072(1)degree s, gamma = 80.773(1)degrees The structure consists of layers of composition [Ge5O14](infinity)(8-) formed by GeO4 tetrahedra and GeO6 octahedra. The c ohesion among them is established through chains of edge-sharing CuO5 squar e pyramids and CuO6 octahedra. This 3D structure contains a two-dimensional channel network were potassium ions are hosted. The downward deviation fro m Curie-Weiss behavior observed under 30 K in the molar magnetic susceptibi lity of K2Cu3Ge5O14 is attributed to the effect of the crystal field splitt ing of the ground term.