Re: What would iron in it's gas form look like?

Hello Marc-Oliver:
You ask about what iron gas would look like.  Your are right that you would 
have to heat the iron to very high temperature to make it a gas.  Also, to 
avoid having the iron vapor oxidize in the air forming iron oxide you 
would have to place it in a vacuum chamber, or a chamber filled with an 
inert  gas like Argon or Helium which will not react with the iron and 
change it into another compound.  

At the temperature that iron vaporizes the atoms will be in a very excited 
state, and the "gas" will be made up of these excited iron atoms.  The 
electrons in the iron molecules will be excited into different electronic 
energy levels and as these electrons become de-excited by collisions with 
the chamber wall or other iron molecules these electrons will lose their 
excess energy and fall back into the initial state.  When that happens a 
light photon equal to the energy level difference between the two states 
will be emitted by the atom and go off into space.  So if you look with a 
spectroscope at your iron gas you would see a line spectrum showing 
the energy levels of iron up to the shortest wavelength which corresponds 
to the highest energy of the iron atoms, i.e. the maximum temperature to 
which you heat any of the atoms.

Observing this line spectrum in telescopes tells the astronomers that there 
is iron in the sun, or on other stars, because they can identify the iron 
from the different lines in the emission spectrum.  However if you looked 
at the gas with your naked eye I think the only thing you would see would 
be the red hot walls of the chamber in which you have placed the iron 
sample, and you would not be able to observe the presence of the iron 
because the walls would look so bright.   However, the wavelengths of the 
light emitted by the walls will be very different from the iron spectrum so 
with a spectroscope you still should be able to see the line spectrum of 
the iron.

Hope this answer tells you what you wanted to know!

R. Bersin...