Lewis acids and bases Lewis acids and bases A Lewis acid is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any species that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a Lewis acid to form a Lewis adduct. For example, NH is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane (MeB) is a Lewis acid as it is capable of accepting a lone
Chemical safety assessment the European Chemicals Agency as part of the respective registration dossier. The purpose is to ensure that the risks related to the substance are controlled. The chemical safety assessment of a substance comprises the following steps: The European Chemicals Agency (ECHA) has developed a software tool to support industry in preparing a Chemical Safety Assessment (CSA) and Chemical Safety Report (CSR). Chesar Beta version can be downloaded from the Chesar website. Chemical Safety Reports are the main end point for data assessment under REACH (the European Community Regulation on chemicals and their safe use, concerning the Registration, Evaluation, Authorisation and