STUDIES ON THE EXISTENCE OF TERNARY AMALGAMS OF ALKALI-METALS - THE SYSTEMS KHG2-RBHG2 AND NAHG2-CSHG2

The ternary systems KHg2-RbHg2 and NaHg2-CsHg2 are investigated by the rmal analyses and X-ray methods. Both systems are quasibinary: Lattice constants and cell volumes of samples in the system KHg2-RbHg2 are in accordance with Vegards law (continous formation of mixed crystals). No ternary compound was detected in this system. NaHg2-CsHg2 however s hows a peritectic decomposition at 300-degrees-C, which can be associa ted to the new ternary compound Na2CsHg6, crystallizing in the hexagon al system (a = 5.080(1) angstrom; c = 11.632(3) angstrom). Due to pron ounced disorder the crystal structure of Na2CsHg6 cannot be determined in full details. In principal it corresponds to an ordered variant of the NaHg2 structure (modified AlB2 type) with a triple c-axis.