How negatively-charged can a helium ion get?

[Green Xenon]

Hi:

 

Is it possible for helium to be negatively-charged? If so, to what extent?

 

 

Thanks,

 

Green Xenon

[Horza2002]

What do you mean to what extent can you make it negative...its either negative or it isn't....theoretically yes you can have He- as you would simply add an electron to the virtual 2s orbital. However, it would be very unstable and would rapidly lose the electron again.

[lemur]

What do you mean to what extent can you make it negative...its either negative or it isn't....theoretically yes you can have He- as you would simply add an electron to the virtual 2s orbital. However, it would be very unstable and would rapidly lose the electron again.

Would density and/or temperature make a difference?

[mississippichem]

Would density and/or temperature make a difference?

 

In a low pressure scenario the [ce] He^-[/ce] ion may last a little longer because it is less likely to collide into another atom. It won't make much difference though. This is an unstable species on effective nuclear charge grounds. The helium nucleus doesn't have enough potential to hold onto that third electron, and the 2s orbital the third electron will be in is much higher in energy than the other two electrons. When a nucleus only has two protons an extra electron is hard to handle, and that electron is likely to be ionized. Also working against this ion's stability is the fact that the third electron will not be spin paired, small radicals tend not to last long.

[lemur]

In a low pressure scenario the [ce] He^-[/ce] ion may last a little longer because it is less likely to collide into another atom. It won't make much difference though. This is an unstable species on effective nuclear charge grounds. The helium nucleus doesn't have enough potential to hold onto that third electron, and the 2s orbital the third electron will be in is much higher in energy than the other two electrons. When a nucleus only has two protons an extra electron is hard to handle, and that electron is likely to be ionized. Also working against this ion's stability is the fact that the third electron will not be spin paired, small radicals tend not to last long.

Interesting. What about if it was in a high-gravity situation, e.g. in orbit of a black hole very close to the event horizon? Would higher gravity increase the amount of energy required to release the 2s electron from the atom? If so (or in the other situation you described in which the He could be temporarily ionized, could it then bond with other atoms and if so is there a way to predict how the compounds might behave? Is this just pointless speculation about how unicorns would fly if they had pterodactyl wings?

Edited January 21, 2011 by lemur

[mississippichem]

Interesting. What about if it was in a high-gravity situation, e.g. in orbit of a black hole very close to the event horizon? Would higher gravity increase the amount of energy required to release the 2s electron from the atom? If so (or in the other situation you described in which the He could be temporarily ionized, could it then bond with other atoms and if so is there a way to predict how the compounds might behave? Is this just pointless speculation about how unicorns would fly if they had pterodactyl wings?

 

Some helium compounds have been observed in the gas phase. They're all metastable [very short lived] and most are just Van der Waals complexes. Compounds that don't have any true LCAO bonds, but just temporary dipoles that cause a brief, weak interaction. It has been postulated that [ce] HeH^+ [/ce] has a true bond, but it is also very short lived. This though isn't even be a negatively charged helium species though. All helium ions are unstable, the anions [negative] more so than the cations [positive].

 

No idea about the black hole thing...ask Leonard Susskind or Stephen Hawking. Might be unicorn speculation though.

[lemur]

Some helium compounds have been observed in the gas phase. They're all metastable [very short lived] and most are just Van der Waals complexes. Compounds that don't have any true LCAO bonds, but just temporary dipoles that cause a brief, weak interaction. It has been postulated that [ce] HeH^+ [/ce] has a true bond, but it is also very short lived. This though isn't even be a negatively charged helium species though. All helium ions are unstable, the anions [negative] more so than the cations [positive].

I was sort of curious if there was enough theoretical connectivity between physics and chemistry to venture predictions about hypothetical elements based on knowledge of their component aspects.

 

 

No idea about the black hole thing...ask Leonard Susskind or Stephen Hawking. Might be unicorn speculation though.

You could ask the unicorns but you would need a frequency translator because they breathe and speak only with pure helium;)

 

 

[Horza2002]

I can't see how being close to a black hole will make any differece. Gravitational effects are dependant on the mass of the two species...in terms of molecules...thes consituents are sooo tiny that the gravitational effects are tiny....millions of times weak than the electronics which are far more important