Studies in the Oxinate derivatives of Chromium

Conditions for preparation of chromium (II) oxinate have been defined. The analysis of the product, as well as the conditions, under which it is precipitated, confirm that the product is initially different from chromium (III) oxinate. The redissolution of chromium (II) oxinate in hydrochloric acid gives a solution with no reducing properties. It has been shown that oxine itself in acidic solutions is not capable of oxidising chromous ions and hence the conversion of chromous to chromic appears to occur at the dissolution stage. Conditions of precipitation of chromium (III) oxinate have been studied in detail and ith as been shown that complete precipitation occurs in the pH range 4–8, on boiling the solution. A chloroform solution of chromium (III) oxinate obeys Beer's law and can be estimated colorimetrically.