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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

The typical purity of aluminium orthophosphate is 98%. All other impurities present at >5% are other inorganic phosphates or other related inorganic substances, similar to the registered substance, and which do not significantly affect its toxicological and ecotoxicological properties. There are no hazardous impurities present within the substance at levels >0.1%.

Aluminium orthophosphate has a reported melting point of >450°C.Aluminium orthophosphate was determined to be slightly soluble(less than or equal to 6.92 x 10-3 g/l of solution at 20.0 ± 0.5°C).

The ion chromatography method applied directly quantified the dissolved phosphate content of each sample solution and these have been corrected to equivalent test material concentrations based on the theoretical phosphate content of the test material. The water solubility of the test material has been determined to be less than or equal to 6.92 x 10-3 g/l of solution at 20.0 ± 0.5°C in un-buffered glass double-distilled water, resulting in sample solution pH’s in the range 6.6 to 7.1. As limited but variable concentrations were determined for the three individual samples, the definitive test concentration range being 2.81 x 10-3 g/l to 6.92 x 10-3 g/l, an overall limit value has been reported as a worst-case scenario for risk assessment. No correlation between initial saturation period and final test material concentration was observed, indicating that variation was not due to either hydrolysis or the failure of a saturation plateau to be achieved. The temperature range of 10°C to 30°C was shown not to have a significant influence on the water solubility of the test material, with concentrations of 4.38 x 10-3 g/l, 2.81 x 10 3 g/l and 3.62 x 10-3 g/l being determined at temperatures of 10°, 20°C and 30°C respectively failing to correlate with their final equilibration temperatures. However, solubility was identified as being significantly influenced by solution pH. Although solubility at pH 9 was only approximately twice that observed in un-buffered water (1.97 x 10-2 g/l with a final solution pH of 8.4), a significant increase was observed at pH 4.0, with a solubility of 0.110 g/l being determined.



The granulometry data gives the following information: The particle size distribution shows that >90% of particles were < 100µm in diameter. Therefore, the Particle size distribution indicates substance is an inhalation risk (a significant proportion of the particles are present at < 100 µm).


Aluminium orthophosphate is not considered to possess any of the following hazardous physico-chemical properties: autoflammability and/or self-ignition, flammability, explosiveness and oxidising properties.