| Compound | Description |
|---|
| hydronium ion | |
| Copper | A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55. |
| Water | A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) |
| Oxygen | An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration. |