Chemical, petrographic, and X‐ray diffraction methods were used to investigate the transformation of CaHPO 4 ·2H 2 O and Ca 8 H 2 (PO 4 ) 6 ·5H 2 O incubated in slightly acid and alkaline soils for 4, 16, and 44 weeks at 25 and 35C. At 25C, hydrolysis of CaHPO 4 ·2H 2 O to Ca 8 H 2 (PO 4 ) 6 ·5H 2 O was confirmed after 4 weeks in soils having a pH value higher than about 7.9, and at 44 weeks the new phase was found in soils with pH values higher than 6.9. Transformation of CaHPO 4 ·2H 2 O to Ca 8 H 2 (PO 4 ) 6 ·5H 2 O increased with increasing pH, temperature, and time of incubation but decreased in the presence of much magnesium. There was no evidence of conversion of added Ca 8 H 2 (PO 4 ) 6 ·5H 2 O to more basic phosphates.
No takes yet. Share an insight, caveat, or question.
Bell et al. (1970) studied this question.