Abstract
There is some doubt and disagreement in the literature as to the usual coordination number of vanadium in the plus three oxidation state. According to the literature, the discrepancy is this: Moeller states that the coordination number of vanadium III is four, indicating a complex compound such as KVF4 which upon ionization would yield K+ and VF-4. On the other hand, Sidgwick states that the coordination number is usually six. He states that he doubts that it is ever lower than six. This indicates a compound such as K,VF6 which upon ionization would yield 3K+ and VF6. | No indication is found in these reference works as to the basis of their statements. The method used in the determination of the coordination number may have been a physical method, such as is described in this paper, or may have been the result of chemical analyses of complex compounds. The physical method described in this paper was conductometric titration. | There is little or no reference in the literature to insoluble complex salts of vanadium exhibiting the plus three oxidation state; therefore, it did not seem feasible to attempt the preparation and analysis of such compounds in order to establish the coordination number of the element. | The purpose of this investigation is to establish which of the conflicting reports of the coordination number of vanadium III is correct.