Task: Text Categorization
Input (English): One coupling reaction links an aryl halide with an acetylide of this metal, while in another reaction it is used as a catalyst to link an alkyne and a bromoalkyne. In addition to the Castro-Stephens and the Cadiot-Chodkiewicz coupling, alkenyl compounds of this element can be created via the Normant reaction. The iodide of this element is a catalyst in the (*) Gatterman-Koch reaction, and this element is present in the A solution of the Fehling test. Gilman reagents contain lithium and this other metal, while the 2+ ion of this element forms a bright blue solution. For 10 points, name this element, a metal used in electroplating and plumbing, with atomic number 29 and symbol Cu.
Output (English): Science