Registration Dossier

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Appearance:

Cesium hydroxide monohydrate is a colourless, odourless inorganic solid.

 

Melting point:

The melting point of cesium hydroxide monohydrate was determined to be 204 °C at 1013.25 hPa.

 

Boiling point:

No boiling point can be determined prior to decomposition starting at approx. 190 °C

 

Density:

Using the gas displacement pycnometry method , the density of cesium hydroxide monohydrate was determined to be 3.53 g/cm3 at 20 °C

 

Particle size distribution:

The particle size distribution of potassium hexadecyl hydrogen phosphate was estimated as averages of three measurements at two test series. The results were as follows: d10: 28.11 um, d50: 213.0 um, d90: 1037 um.

Vapour pressure:

The determination of the vapour pressure of cesium hydroxide monohydrate was performed according to OECD Guideline 104 and EU Method A.4 The vapour pressure of the test item at 20 °C was interpolated from the Antoine equation.It was determined to be < 0.1 hPa (at 20 °C).

 

Partition coefficient:

In accordance with column 2 of REACH Regulation (EC) No 1907/2006 Annex VII, the test on partition coefficient n-octanol/water (required in REACH Regulation, Annex VII, section 7.8) does not need to be conducted if the substance is inorganic. Cesium hydroxide monohydrate, respectively cesium hydroxide anhydrous is an inorganic compound. Therefore the estimated log Pow is estimated to be ≤0 due to its salt character and good water solubility.

 

Water Solubility:

The water solubility of cesium hydroxide monohydrate was determined to be greater than 1000 g/L at 20 +/- 0.5 °C. Therefore, the test item is very soluble.

 

Surface tension:

The determination of the surface tension of an aqueous solution of cesium hydroxide monohydrate was performed according to OECD Guideline 115 and EU Method A.5. The surface tension of the test item was determined in ten measurements. The measurements revealed values of 70.34 to 71.75 mN/m at 20 °C. The surface tension of cesium hydroxide monohydrate was determined as 71.1 mN/m at 20°C.

 

Flash point:

As cesium hydroxide monohydrate, respectively cesium hydroxide anhydrous is a solid at room temperature, the determination of the flash point is scientifically unjustified and therefore was not performed. Instead, a test on flammability for solids upon contact in air was conducted (see below).

 

Auto flammability:

Up to about 400 °C no exothermic reaction of the sample was observed.

 

Flammability:

Because of the result of the preliminary test, cesium hydroxide monohydrate is considered non flammable. No flammability in contact with water and no pyrophoric properties are expected for the test item.

 

Explosiveness:

As the sample was neither shock sensitive nor thermally or friction sensitive, according to the criteria of the EU Method A.14, cesium hydroxide monohydrate is not representing an explosive hazard and has not to be considered to present a danger of explosion.

 

Oxidizing properties:

Test on oxidizing properties of cesium hydroxide monohydrate was performed according to the EU Method A.17. With regard to all test results the test item is assessed to have no oxidizing properties.

Stability in organic solvents and identity of relevant degradation products:

In accordance with column 2 REACH Regulation (EC) No 1907/2006 Annex IX section 7.15, the study which examines stability in organic solvents does not need to be conducted as the test substance cesium hydroxide monohydrate, respectively cesium hydroxide anhydrous is an inorganic substance.

 

Dissociation constant:

The dissociation constant of the test item (at 24 °C) was determined to be 11.6.

 

Viscosity:

The study which examines viscosity and is required according to REACH Regulation (EC) No 1907/2006 Annex IX section 7.17 does not need to be conducted as the test substance cesium hydroxide monohydrate, respectively cesium hydroxide anhydrous is not a liquid.