Raman spectra of the compound NbCl5 . GaCl3 in the solid and in the molten state

Niobium(V) chloride and gallium(III) chloride exist in the solid state as dimer molecules. A 1:1-mixture of these two compounds reacts in the melt to a new molecule build of octahedron and tetrahedron sharing an edge. The existence of this new molecule can be seen in the Raman spectra. The niobium is loacted in the center of the octahedron, while the gallium is surrounded tetrahedrally. This molecule exists in the melt some degrees beyond the melting point too. But with rising temperature of the melt it dissociates in its components, of which the dimer Ga2Cl6 is stable in the molten state over a wide temperature range while the dimer Nb2Cl10 dissociates with rising temperature in monomer NbCl5 molecules. (author)