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
NASA Star and Exoplanet Database public data to support the search for and characterization of extra-solar planets (exoplanets) and their host stars. The data include published light curves, images, spectra and parameters, and time-series data from surveys that aim to discover transiting exoplanets. All data are validated by the NStED science staff and traced to their sources. NStED is the U.S. data portal for the CoRoT mission. As of December 2011, SDtED is no longer in operation. Most data and services have been transferred to the NASA Exoplanet Archive. Data are searchable either for an individual star or by stellar and planetary properties. NStED offers