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The
geometry and symmetry of the elements |
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By definition elements are composed of only one type of atom species.
Therefore |
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their atomic structures lend themselves readily to being modeled as packings
of |
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equal radius spheres. The majority of elements exhibit either FCC, HCP,
or BCC |
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packing of their atoms. |
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H |
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He |
Li |
Be |
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B |
C |
N |
O |
F |
Ne |
Na |
Mg |
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Al |
Si |
P |
S |
Cl |
Ar |
K |
Ca |
Sc |
Ti |
V |
Cr |
Mn |
Fe |
Co |
Ni |
Cu |
Zn |
Ga |
Ge |
As |
Se |
Br |
Kr |
Rb |
Sr |
Y |
Zr |
Nb |
Mo |
Tc |
Ru |
Rh |
Pd |
Ag |
Cd |
In |
Sn |
Sb |
Te |
I |
Xe |
Cs |
Ba |
La |
Hf |
Ta |
W |
Re |
Os |
Ir |
Pt |
Au |
Hg |
Tl |
Pb |
Bi |
Po |
At |
Rn |
Fr |
Ra |
Ac |
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Lanthanides |
Ce |
Pr |
Nd |
Pm |
Sm |
Eu |
Gd |
Tb |
Dy |
Ho |
Er |
Tm |
Yb |
Lu |
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Actinides |
Th |
Pa |
U |
Np |
Pu |
Am |
Cm |
Bk |
Cf |
Es |
Fm |
Md |
No |
Lr |
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FCC |
HCP |
BCC |
CP |
HP |
Diamond |
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Table 2 - Periodic table of the elements showing atomic packing
arrangement |
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(all elements, including gases, considered to be in their solid state) |
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The BCC structure is favored by elements with low numbers of valence
electrons. |
Elements with larger numbers of valence electrons favor the closer packed
FCC and |
HCP
structures. |
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Face
centered cubic (FCC) structure elements |
Ac,
Ag, Al, Ar, Au, Ce, Cu, In, Ir, Kr, Ne, Ni, Pb, Pb, Pd, Pt, Rh, Th, Xe |
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Crystal lattice |
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Figure 45 - FCC
elements crystal lattice |
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click image to enlarge |
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The above image shows the ABC staggered arrangement of the successive layers |
of
atoms characteristic of the FCC lattice. The view is taken looking
down on the |
(111) plane which is comprised of atoms in the triangulated closest packed
array. In |
the
process of building this model of the lattice the structural stability
afforded by the |
omni-triangulation of 3D space can be appreciated first hand. |
Back to
Knowhere |
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Page
31 - Structure matters - FCC elements |
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