AN ACCURATE METHOD OF IODOMETRIC TITRATION TO MEASURE COPPER VALENCE OF HIGH-T-C SUPERCONDUCTORS

The double iodometric titration is the method widely used to determine copper valence of high-T-c superconductors. There are some problems t hat remain to be solved, and certain procedures are used: adding KSCN to release adsorbed iodine, adding HN4HF2 to eliminate the interferenc e of some dopants, and using a new calculating equation to accurately calculate experiment results. Al- and Fe-doped samples were prepared a nd their copper valence, 2+p, was determined by the improved double io dometric titration method. With these samples, how to use the above pr ocedures to improve experiment results is discussed. We find that the iodometric titration method described here can be used to determine co pper valence and oxygen content for doped and undoped samples with hig h accuracy.