low bioactivity, negligible copper is absorbed. It is used when welding with copper alloys. A copper oxide electrode formed part of the early battery type known as the Edison–Lalande cell. Copper oxide was also used in a lithium battery type (IEC 60086 code "G"). Pyrotechnics and fireworks Used as moderate blue coloring agent in blue flame compositions with additional chlorine donors and oxidizers such as chlorates and perchlorates. Providing oxygen it can be used as flash powder oxidizer with metal fuels such as magnesium, aluminium, or magnalium powder. Sometimes it is used in strobe effects and thermite compositions as crackling stars effect. Similar compounds An example of natural copper(I,II) oxide is the mineral paramelaconite, Cu+2Cu2+2O3. See also Patina References External links National Pollutant Inventory - Copper and compounds fact sheet Copper oxides project page CDC - NIOSH Pocket Guide to Chemical Hazards Copper(II) compounds Semiconductor materials Pyrotechnic colorants Transition metal oxides Glass dyes