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Physical & Chemical properties

Partition coefficient

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partition coefficient
Type of information:
Adequacy of study:
weight of evidence
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
Please refer to the QMRF and QPRF files provided under the section attached justification.
according to guideline
other: REACH guidance on QSAR R.6
Principles of method if other than guideline:
Estimates the log octanol-water partition coefficient, log KOW, of chemicals using an atom/fragment contribution method.
GLP compliance:
Type of method:
calculation method (fragments)
Partition coefficient type:
Specific details on test material used for the study:
Key result
log Pow
Partition coefficient:
25 °C
Remarks on result:
other: The substance is not within the applicability domain of the model.

KOWWIN Program (v1.68) Results:



Log Kow(version 1.68 estimate): -0.77



CHEM  : Phosphoric acid


MOL WT : 98.00














 -OH [phosphorus attach]                 





 Equation Constant                        



Log Kow



Using KOWWIN v1.68 the logPow of phosphoric acid was calculated to be -0.77 at 25 °C. The substance is not within the applicability domain of the model. Thus the estimation may be less accurate.
Executive summary:

The logPow was calculated using KOWWIN v1.68 as part of EPISuite v4.11 from US Environmental Protection Agency.

Using KOWWIN v1.68 the log Kow of the test item was calculated to be -0.77 at 25 °C (EPI Suite).

The adequacy of a prediction depends on the following conditions:

a) the (Q)SAR model is scientifically valid: the scientific validity is established according to the OECD principles for (Q)SAR validation;

b) the (Q)SAR model is applicable to thequery chemical: a (Q)SAR is applicable if the query chemical falls within the defined applicability domain of the model;

c) the (Q)SAR result is reliable: a valid (Q)SAR that is applied to a chemical falling within its applicability domain provides a reliable result;

d) the (Q)SAR model is relevant for the regulatory purpose.


For assessment and justification of these 4 requirements the QMRF and QPRF files were developed and attached to this study record.


Description of the prediction Model

The prediction model was descripted using the harmonised template for summarising and reporting key information on (Q)SAR models. For more details please refer to the attached QSAR Model Reporting Format (QMRF) file. 


Assessment of estimation domain

The assessment of the estimation domain was documented in the QSAR Prediction Reporting Format file (QPRF). Please refer to the attached document for the details of the prediction and the assessment of the estimation domain.

partition coefficient
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance is inorganic

Description of key information

In accordance with column 2 of REACH Regulation (EC) No 1907/2006, Annex VII, section 7.8, the test on partition coefficient n-octanol/water does not need to be conducted if the substance is inorganic. Lithium phosphate is an inorganic compound. Furthermore, lithium phosphate completely dissociates in water forming lithium cation and the corresponding phosphate anion. For risk assessment purposes a partition coefficient of the anion (phosphoric acid) in water was estimated with EPI Suite v4.10.The theoretical, calculated (EPIWIN) log Pow of phosphoric acid is -0.77.


Key value for chemical safety assessment

Log Kow (Log Pow):
at the temperature of:
25 °C

Additional information

Lithium phosphate quickly dissociate in water forming lithium and phosphate ions. Therefore a laboratory study determining the partition coefficient is technically not feasible and the partition coefficient of the corresponding anion (phosphoric acid) was calculated. The calculation of the partition coefficient of phosphoric acid with EPI Suite v4.10 can be seen as rough estimation as only a few inorganic compounds were included in the training data set of the program.
The partition coefficient of phosphoric acid was estimated using KOWWIN v1.68 embedded in EPI Suite v4.10 of EPA’s Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC). The program is a screening level tool and estimates the log octanol/water partition coefficient log Pow of chemicals using an atom/fragment contribution method. Phosphoric acid has a molecular weight of 98 g/mol and therefore fits to the applicability domain of this model. A log Pow -0.77 was derived for phosphoric acid.