Premium
Kinetics of Isotope Exchange on Hydroxyapatite
Author(s) -
Kukura M.,
Bell L. C.,
Posner A. M.,
Quirk J. P.
Publication year - 1973
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1973.03615995003700030016x
Subject(s) - stoichiometry , isotope , kinetics , chemistry , diffusion , aqueous solution , recrystallization (geology) , ion exchange , isotopes of calcium , mineralogy , thermodynamics , geology , ion , organic chemistry , calcium , paleontology , physics , quantum mechanics
The kinetics of exchange of 32 P and 45 Ca in aqueous solution with synthetic, stoichiometric hydroxyapatitie was followed up to 200 hours. Seventy percent of the total exchange occurred in 1 hour, and isotopic equilibrium was reached at approximately 40 hours. Using McKay (13) plots, the exchange reaction was shown to be heterogeneous. Diffusion of isotope through solution “compartments” was considered to be rapid in relation to exchange occurring at the solid surface. The nature of the exchange curve was explained by the differing energies of activation of exchange for surface atoms located at different positions on the crystal landscape. The use of well‐crystallized, stoichiometric hydroxyapatite resulted in the establishment of a well‐defined isotopic equilibrium (11) with little evidence of loss of isotope through intracrystalline diffusion or recrystallization.