Determining rhenium against a background of large amounts of molybdenum by the use of isopolycompounds and heteropolycompounds

There are close similarities in properties between rhenium and molybdenum on account of their electronic structures and similar atomic and ionic radii and ionization potentials which cause considerable difficulties not only in the technological separation of rhenium and molybdenum but also in determining when they are present together, according to the authors. In this paper, a spectrophotometric method of determining perrhenate against a background of large amounts of molybdate by the formation of isopolycompounds IPC and heterpolycompounds HPC is discussed. Systematic errors have been checked by regression analysis, and it has been found that the value from the control experiment represents a realistic and adequate correction for the constant error. The method has been checked out on model solutions and has been applied to the analysis of Re-Mo and Re-Ni-Fe alloys as well as to industrial solutions containing ammonia, sulfuric acid, and nitric acid