The published data on the complexes of zirconium with the aminopolycarboxylic acid, xylenol orange (X0), give conflicting evidence as to their composition.
BABKO ANI) SHTORALO~
report a I :I SO-zirconium complex in I N hydrochloric acid. and a 2 :I complex at PH 2. BABKO AND GRIDCIIINA~ describe the presence of a polyion, in 0.01-2.0 N hydrochloric acid media, with the structure -Zr(OH)a-0-Zr(OH)rOwhich undergoes decomposition to form complexes with X0.
BUDGSINSKY"
postulates a complex with 2 moles of zirconium per I mole of X0. CrfENci4-fi reports I :I complexes for both zirconium and hafnium in 0.2-1.0 N perchloric acid media, but also suggests that the complexes may have some other composition when excess of X0 is present. No experimental evidence is offered to support this latter suggestion.
EXI'ERISIENTAL
Afiparatus and reagents
Absorption measurements were carried out on a Zeiss Model RPQ 20AV double-beam recording spcctrophotometer using r-cm quartz cells. Standard Zr sohtion. xo-3 M solution in K N perchloric acid prepared from Merck analytical grade ZrOClz -8HsO. Standard Hf sol&ion. IO -3 M solution in I N perchloric acid prepared from Johnson, Matthey & Co. spectroscopically standardised HfOClz l 8HzO containing 0.47% Zr. Xylmol orange. I0 -3 M solution prepared from B.D.H. laboratory reagent. Pevclrlovic acid. B.D.H. AnalaR product was used.