Iron is an example of which type of bond when it combines with another element to form a compound?

Iron, when combined with another element to form a compound, typically exhibits a metallic bond. This type of bonding occurs between metal atoms and is characterized by a "sea of electrons" that are free to move around, which allows for conductivity and malleability. In the case of iron, it is a metal that can also participate in ionic or covalent bonding under specific conditions, particularly when reacting with non-metals or different elements.

However, the key aspect of metallic bonding is the ability of iron to share its electrons with other metal atoms; thus, it creates a lattice of positively charged metal cations immersed in a sea of delocalized electrons. This is distinct from ionic bonding, which involves the transfer of electrons between metals and non-metals, and covalent bonding, where electrons are shared between non-metal atoms. Hydrogen bonds are specific interactions that occur between molecules and are not relevant to the bonding of metals.

Iron's typical behavior in forming compounds is best described by metallic bonding, making it the correct answer in the context of the question.