A process for producing a homogenous multi compound system which is hydroxide- and/or oxide-based includes a first alternative process comprising providing a first and a second refractory metal in respective hydrofluoric solutions, and mixing the first and second hydrofluoric solutions to provide a mixed hydrofluoric solution comprising a dissolved first and second refractory metal. A second alternative process comprises dissolving the first and the second refractory metal in an alternative mixed hydrofluoric solution. The mixed hydrofluoric solution or the alternative mixed hydrofluoric solution is precipitated with a precipitant to provide a solids mixture in a suspension. The first and second refractory metal is from the group consisting of Mo, W, Nb, Re, Zr, Hf, V, Sb, Si, Al, and Ta. The first and second refractory metal are different. At least one of the first and second refractory metal is provided as a fluoro and/or as an oxyfluoro complex.