Abstract
Solubility isotherms for CaHPO4 · 2H2O, dicalcium phosphate dihydrate, DCPD, in the ternary system Ca(OH)2 - H3PO4 - H2O were determined at 5, 15, 25, and 37.5 °C in the pH range 3.5 - 7; the relative positions of the isotherms indicate that DCPD has a negative thermal coefficient of solubility. The solubility product, K s , of DCPD and the stability constants K x and K y for the ion pairs and , respectively, were obtained as functions of temperature by the use of a generalized least squares procedure subject to three condition functions - constancy of the solubility product, electrical neutrality in the solution, and congruent dissolution of the solid. The equations obtained are The existence of a maximum in K s in the neighborhood of 25 °C is plausible on the basis of available thermodynamic data for DCPD. Thermodynamic functions are reported for the solution of DCPD and for the association of the ion pairs.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of research of the National Bureau of Standards. Section A, Physics and chemistry
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.