<P> The strong bonding of metals in the liquid form demonstrates that the energy of a metallic bond is not a strong function of the direction of the metallic bond; this lack of bond directionality is a direct consequence of electron delocalization, and is best understood in contrast to the directional bonding of covalent bonds . The energy of a metallic bond is thus mostly a function of the number of electrons which surround the metallic atom, as exemplified by the Embedded atom model . This typically results in metals assuming relatively simple, close - packed crystal structures, such as FCC, BCC, and HCP . </P> <P> Given high enough cooling rates and appropriate alloy composition, metallic bonding can occur even in glasses with an amorphous structure . </P> <P> Much biochemistry is mediated by the weak interaction of metal ions and biomolecules . Such interactions and their associated conformational change has been measured using dual polarisation interferometry . </P> <P> Metals are insoluble in water or organic solvents unless they undergo a reaction with them . Typically this is an oxidation reaction that robs the metal atoms of their itinerant electrons, destroying the metallic bonding . However metals are often readily soluble in each other while retaining the metallic character of their bonding . Gold, for example, dissolves easily in mercury, even at room temperature . Even in solid metals, the solubility can be extensive . If the structures of the two metals are the same, there can even be complete solid solubility, as in the case of electrum, the alloys of silver and gold . At times, however, two metals will form alloys with different structures than either of the two parents . One could call these materials metal compounds, but, because materials with metallic bonding are typically not molecular, Dalton's law of integral proportions is not valid and often a range of stoichiometric ratios can be achieved . It is better to abandon such concepts as' pure substance' or' solute' is such cases and speak of phases instead . The study of such phases has traditionally been more the domain of metallurgy than of chemistry, although the two fields overlap considerably . </P>

What type of structure do metallic bonds have