A calcined carbonate used to absorb the carbon dioxide evolved during a coal gasification process.

1. A chemical whose reaction rate with another chemical increases because the other substance undergoes another reaction.

2. A species that accepts electrons, protons, electron pairs, or molecules such as dyes.

An impurity element that increases the number of holes in a semiconductor crystal such as germanium or silicon; aluminum, gallium, and indium are examples. Also known as acceptor impurity; acceptor material.