Toll definition, a payment or fee exacted by the state, the local authorities, etc., for some right or privilege, as for passage along a road or over a bridge. See more. Dictionary.com
The International Union of Pure and Applied Chemistry (IUPAC, /ËaÉªjuËpÃ¦k/ or /ËjuËpÃ¦k/) is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science (ICSU).
In the old IUPAC system the letters A and B were designated to the left (A) and right (B) part of the table, while in the CAS system the letters A and B are designated to main group elements (A) and transition elements (B).