COMPUTER ANALYSIS OF POTENTIOMETRIC AND SOLVENT EXTRACTION STUDIES OF THE FLUORIDE COMPLEXES OF HAFNIUM
Measurements on fluoride-containing hafnium solutions in 3M perchlorate media at 25 deg C by precision potentiometry and by solvent extraction distribution using thenoyltrifluoroacetone (TTA) and tri-n-octylphosphine oxide (TOPO) were subjected to high-speed digital computer analysis and the results interpreted in terms of the nature and stabilities of complex hafnium fluoride species present. Potentiometric hydrogen ion measurements with a quinhydrone half-cell gave the formation function for the mononuclear series of hafnium fluoride complexes from an average ligand number of about 2 to a maximum value of about 6. At radioactive trace concentrations of hafnium, TTA extracted only Hf/ sup 4+/, giving useful information on the formation of the first four fluoride complexes. TOPO extracted two species, one containing two fluoride ions per hafnium ion and the other none, and the data were interpretable in terms of five aqueous-phase species including HfF/sub 5/. The TTA and potentiometric data were combined in a weighted, non-linear regression machine program to calculate simultaneously the stepwise formation constants of the first six mononuclear fluoride complexes of hafnium. The values obtained were log k/sub 1/ = 4.89, log k/sub 2/ = 3.67, log k/sub 3/ = 2.97, log k/sub 4/ = 2.77, log k/sub 5/ = 1.55, and log k/sub 6/ = 2. where k/sub n/ = (HfF/sub n/) (H/sup +/)/(HfF/sub n-i/) (HF). (auth)
- Research Organization:
- Oklahoma State Univ., Stillwater; Massachusetts Inst. of Tech., Cambridge. Dept. of Chemistry; and Massachusetts Inst. of Tech., Cambridge. Lab. for Nuclear Science
- DOE Contract Number:
- AT(30-1)-905
- NSA Number:
- NSA-17-010600
- OSTI ID:
- 4734541
- Report Number(s):
- TID-15939
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- United States
- Language:
- English
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