Apart from mercury, which is a liquid, metals are solid at room temperature. The atoms from which metals are constructed are held together by metallic bonds. It is these metallic bonds which give metals some of their distinctive properties. The usual metallic state consists of a number of regularly-spaced crystals formed into a lattice. Metals are therefore quite different from materials like glasses which are amorphous because the atoms which make up metals are ordered so that the distance between them is the shortest possible - for maximum compactness (Guinier 1989: 88). Whereas metals exhibit longrange order, glasses, on the other hand, only exhibit short range order (that is they are only ordered over short distances) and their 'structure' is not predictable.