Chromium tris(dihydrogen phosphate)

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

In-house data assessment.
Substance is manufactured in water

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

Liquid materials was concentrated by boiling until precipitation

Principles of method if other than guideline:

Substance is supplied as water-solution and investigation was performed to confirm solublity.
The test solution was concentrated by boiling to ascertain its maximum solubility and then stirred to confirm that it was stable.
Confirmatory analysis was performed by ICP

GLP compliance:

no

Type of method:

other: Observations

Specific details on test material used for the study:

Batch number of test material: B-05-3234

Key result

Water solubility:

ca. 450 g/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

ca. 1.3

Details on results:

pH 1.3 Soluble at 450 g/l
Above pH 2.3, solublity was greatly reduced
At below 10 g/l, precipitation was seen and at 100 mg/l, there was still limited solubility.

Serial dilution showing reduction in solublity when diluted.

0.1g / 0.1 ml water   = Soluble

0.1g / 0.5 ml water   = Soluble        

0.1g / 1 ml water      = Soluble        

0.1g / 2 ml water      = Soluble 

0.1g / 10 ml water    = Not soluble 

0.1g / 100 ml water  = Not soluble 

0.1g / 1000 ml water = Not soluble 

Conclusions:

The solubility is very pH dependant with precipitation at neutral or alkaline pH resulting in very low water solubility expected under environmental conditions.
The substance supplied is very acidic and remains in solution.
Dilution to less than 100 mg/l also led to precipitation

Executive summary:

Soluble at high concentrations and under acidic conditions

Dilution or raising pH will lead to precipitation of chromium salts (hydroxide?)

Description of key information

Under acidic conditions, the substance is miscible in water, but once raised to pH 5.5 or higher, the substance will precipitate (other salts will form). Solublity at pH 5.5 is < 15 mg/l.

Under environmental conditions, solublity of chromium is expected to be very low and close to some background environmental concentrations.

Key value for chemical safety assessment

Water solubility:

1 000 g/L

at the temperature of:

20 °C