Registration Dossier

Administrative data

vapour pressure
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the melting point is above 300°C
Justification for type of information:

The vapour pressure of a substance is defined as the saturation pressure above a solid or liquid substance. Several different measuring methods are listed for the measurement of the vapour pressure of solids and liquids. However, the vapour pressure does not need to be measured due to technical reasons if calculations indicate that the value is significantly less than 10-5 Pa. Lead tetroxide (“minium”) is a solid inorganic substance which has a melting point above 550 °C. In view of this, the volatility of this substance can therefore be safely assumed to be negligible, i.e. below the level of significance (10-5 Pa).

Lead metal is stated to have a vapour pressure of 133 Pa at a temperature of 1000 °C. Based on a volatilisation enthalpy of Hvap = 177.9 kJ/mol, this vapour pressure can be recalculated with the aid of the Clausius-Clapeyron equation to a vapour pressure of 8.2 * 10-7 Pa at the melting temperature of lead (326°C). Thus, it can safely be assumed that metallic lead will have a negligible vapour pressure at 20°C. Concerning lead tetroxide, the oxidation status may be anticipated to reduce volatility even further.

In conclusion, in accordance with REACH Annex VII, Section 7.5, Column 2, testing of lead tetroxide is not required

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion