| |
Properties
of Metallic Bonding
· The electron gas gives
the material a high electrical and thermal conductivity.
·
Free
electrons make metals opaque and highly reflecting in the visible and
infra-red; transparent in the ultraviolet.
· The non-specific
nature of the bond allows many "impurity" atoms to be in the
structure. Alloys are easily formed.
· The non-directional
nature of the bond makes plastic deformation relatively easy.
· Typical
binding energies (eV per atom): Na -> 1.1; Ag -> 3.0;
Ni -> 4.4
· Crystal structure: Na -> bcc; Ag ->
fcc; Ni -> fcc; Al -> fcc; Ti -> hcp; Fe -> bcc.
· Nearest
neighbor distances: Na -> 0.37 nm; Ag -> 0.29 nm; Ni
-> 0.25 nm; Ti: a = 0.29 nm, c = 0.47 nm; Fe -> 0.29 nm.
· Melting
points (Celsius): Na -> 98.7; Ag -> 961; Ni -> 1453;
Ti -> 1668
|
|
