

F Orbitals
Name: peter tran
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: 1999
Question:
Can anyone answer this question? The question is on
F Orbitals. Please tell me how this looks like.
I've gone to many libraries but I cound't find anything.
Replies:
You have asked a very difficult question. First, because it requires
a verbal written response rather than a facetoface interaction with
a blackboard that we can draw on, and secondly because most of us have
probably never seen drawings of forbitals. After all, drawings are only
two dimensional and the orbitals are 3d, well 4d since there are three
coordinates (x,y,z) and the magnitude of the orbital. It is very
difficult to draw 4dimensional objects on a 2d paper. To make it
easier, one convention is to try to represent the orbital as a funny
shaped balloon that would "contain" a certain amount (say 95%) of the
electron density of the selected orbital. Using this convention an
sorbital looks like a perfectly round ball. Any of the porbitals (there
are 3 of them) look like two snocones arranged so the cups point
directly at each other. The dorbitals (except for d(z^2) are
_represented_ as four snocones, all in the same plane and with their
cups pointing at the center (like the blade of a fan). Notice that
there is a progression here, as we go from s to p to dorbitals we go from
0 to 1 to 2 nodal planes (a nodal plane is a plane that can be placed
between two or more  of the balloons without touching any of them).
The next step, forbitals, will have 3 nodal planes. I will attempt to
describe what ONE of them might look like  there are a total of 7
and will not all look alike (notice the dorbitals don't all look alike!)
Now to describe what ONE of the forbitals might look like. Remember,
it has to have 3 nodal planes. Let's just use the xy, xz, and yz
planes of cartesian coordinate systems. If each plane were a sheet
of plastic it would divide space up into 8 octants (ask a geometry
teacher if you cannot "see" this). Now, place a snocone in each
octant with the point toward the origin. Use 4 red snocones and
4 bluesnocones and make sure that you alternate red and blue when
going from one octant to its neighboring octant (i.e., when crossing
a single sheet of plastic). The colors of the snocones represent
the sign of the wavefunction in that region of space, either positive
or negative (which you want to call positive and where you put the
first one is completely arbitrary). Remeber, the signs do NOT represent
an electrostatic charge  electrons are always negatively charged!
The sign is ONLY the sign of the function used to mathematically
represent the magnitude of the electron's wave function in that region
of space. Also, you should be aware that one reason more
people aren't concerned about the forbitals is that they aren't important
in most chemical bonds.
Hope this helps!
Greg
Good news! I just found pictures for forbitals in "Quanta: A Handbook
of Concepts, 2nd Ed.", pg 119. The orbital I described is the f(xyz)
orbital.
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Update: June 2012

