In galena (lead sulfide), the ions are held together by ionic bonds. Ionic bonding is a type of chemical bond formed by the electrostatic attraction between oppositely charged ions. In the case of galena, the lead ions (Pb2+) are positively charged, while the sulfide ions (S2-) are negatively charged. The attraction between these oppositely charged ions holds the compound together.

The strength of an ionic bond depends on the charges of the ions and the distance between them. The greater the charges of the ions and the shorter the distance between them, the stronger the ionic bond. In galena, the lead and sulfide ions have relatively high charges (2+ and 2-, respectively) and are held relatively close together, resulting in a strong ionic bond.

Ionic bonding is a common type of chemical bond found in many inorganic compounds, including salts, oxides, and hydroxides.