Silicic acid, lithium magnesium sodium salt

pH

Administrative data

Endpoint:

pH

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Carried out by trained chemists using calibrated equipment under laboratory conditions

Data source

Reference

Reference Type:

other company data

Title:

Unnamed

Materials and methods

Principles of method if other than guideline:

The pH of a 2% dispersion of the sample in demineralised water is measured 2 - 24 hours after preparation.
Accurately weigh out 196g of demineralised water on a calibrated balance, into a 400 cm3 squat form plastic beaker. Temperature of water must equal 25 deg C +/- 1degC. Immerse the head of a Silverson mixer in the water. Weigh out accurately, 4g of sample, adjust the speed of Silverson to
6250 rpm +/- 250 rpm. Slowly add the sample to the demineralised water. Continue mixing for 10 minutes.Take care that the entire sample is wetted and dispersed. If clumping occurs, repeat the test. After 10 minutes switch off the mixer. Transfer the dispersion to a screw top polythene bottle. Store at 25 degC +/- 1degC in an incubator. The measurement can be made at any time after 2 hours after placing the sample in the incubator.
Following the manufacturer’s instructions, calibrate the pH meter using the pH 7.0 and pH 10.0 buffer solutions. (Use fresh buffer solutions).
Immerse the electrodes in the test solution. Swirl slowly to allow mixing of the sample and for the reading to equilibrate.Once a constant value is reached, record the pH value on the worksheet

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Silicic acid, lithium magnesium sodium salt

EC Number:

258-476-2

EC Name:

Silicic acid, lithium magnesium sodium salt

Cas Number:

53320-86-8

Molecular formula:

Na0.7[Li0.3Mg5.5Si8O20(OH)4]

IUPAC Name:

magnesium(2+) lithium(1+) sodium bis(oxosilanebis(olate))

Results and discussion

pH value

pH value:

9.97

Temp.:

25 °C

Concentration:

2 other: % by weight

Remarks on result:

other: Measurement carried out in demineralised water

Applicant's summary and conclusion

Executive summary:

The pH of this substance can only be measured once the material has been dispersed in an aqueous medium. The substance itself is a solid. Because the substance forms a gel at concentrations > 2% by weight in water, the pH measurement is carried out at 2% in demineralised water at 25 deg C. The natural pH of Laponite® a commercially available product of this substance, varies between 9.8 - 10.6 but the pH of the test material in this case was found to be 9.97