Oxidation of Fluorine

[budullewraagh]

Thats not true in general. There are some oxides of nitrogen in which three electrons are shared. And then you have orgaincs where a whole bunch of electrons may be delocalized.

last i checked, 3 electrons cannot be shared in a single hybrid orbital. it goes against the idea of having electron pairs in orbitals. then again, i may be mistaken. could you substantiate that thought?

 

in polyatomics there are generally coordinate covalent bonds. this means that one atom provides both electrons required to make a bond, which is what makes ions. in the NO3 ion, the N is at +5, while 3 of the O atoms are at -2. of course this cannot happen unless one of the oxygen provides both electrons for the bond, which happens.

[pulkit]

http://en.wikipedia.org/wiki/Nitrous_oxide

 

This compound has resonance. If you look at the structure, you will see that it has an odd number of electrons involved in bonds. The resonance hybrid would have one elctron delocalized over the molecule.

[budullewraagh]

ah right. forgot about resonance for a moment. good call.

[SurfSciGuy]

 

 

FMnO4' date=' FO-, FNO3, etc.

 

[/quote']

 

none of those compounds contain F+

 

ok then, if they say it.

 

There is no "say" about it, that is a fundamental rule of oxidation state theory, which as I have said is only an approximation (as there is no discete ionic states in the molecules).

 

apparently the NO3- group loses its electron to the fluorine. that's some pretty crazy stuff.

 

Yes it is! The F atom is the most electronegative in the molecule so it will pull electron density towards it. You have massively oversimplified the model of the molecule by assuming that it is a discrete pair of ions, this is incorrect. Quantum modelling calculations (which are also inaccurate, but a damn site better than oxidation state theory) show that the flourine has significant electron density around it in the ground state (indicating that it probably carries a delta - partial charge). The outer electrons are most likely to be dissociated over the molecule (i.e. full charges are unlikely to reside on one individual atom. A bond between oxygen and fluorine will be polarised with the flourine having a delta -ve charge (and, neccesarily, the oxygen having a delta +ve charge) because fluorine is more electronegative (i.e. it's nucleus has a higher charge denisty and very low inner shell shielding effects and so exerts a larger attractive force than the oxygen nucleus on the bonding electrons).

[budullewraagh]

Yes it is! The F atom is the most electronegative in the molecule so it will pull electron density towards it. You have massively oversimplified the model of the molecule by assuming that it is a discrete pair of ions, this is incorrect.

dude of course i dont think theyre just ions. a nitrate group is electronegative like few others and makes a pretty SP hybrid orbital with fluorine. i would like to add that the fact that fluorine has an S as its outermost orbital makes it easier to ionize.

[Primarygun]

I use http://en.wikipedia.org/

this encyclocpedia too!

[SurfSciGuy]

dude of course i dont think theyre just ions. a nitrate group is electronegative like few others and makes a pretty SP hybrid orbital with fluorine. i would like to add that the fact that fluorine has an S as its outermost orbital makes it easier to ionize.

 

Which atom makes the sp hybrid (an O I presume)? Molecules or multiatomic ions cannot have an electronegativity as such (it is an elemental property). Nitrate ions do not oxidise Fluorine to F+. The Fluorine is the most electronegative element in the system and hence it will carry a delta -ve charge in a polar covalent bond (with the O I think). Fluorine has the highest non-noble gas first ionization energy (The noble gases are very difficult to ionise, in fact they are very difficult to do anything with) so it is not easy to ionise at all!

[YT2095]

there are no freestanding oxides of Fluorine that I`m aware of. there are IONS (fluorates, ites, perfluorates etc..) but not as a compound

[apathy]

There is no easy way to store HF' date=' it reacts with virtually everything.

It can even dissolve glass.[/quote']

 

Funny, I must not have the Nalgene bottle of HF under my hood.

[budullewraagh]

it will attack most things, but can be stored. hey, if pentafluoroantimonic acid can, HF can.

[Primarygun]

Can quantum mechanic predict which chemical decomposes naturally?

Why is hydrogen carbonate so unstable while sodium carbonate is so stable?

[pulkit]

it will attack most things, but can be stored. hey, if pentafluoroantimonic acid can, HF can

 

Yeah of course it can be stored, but it does cause an odd headache or two when trying to store it. All i meant to say was that glass is no good for this purpose

[pulkit]

Why is hydrogen carbonate so unstable while sodium carbonate is so stable?

 

Hydrogen carbonate is nothing but carbon dioxide dissolved in water. Like all gases dissolved in liquids, there is a saturation point. Plus any heating will immediately release the dissolved gas. Hydrogen carbonate can't be isolated as a solid, it mostly occurs when carbon dioxdie is released in a reaction taking place in an aqueous medium.

[Primarygun]

Why do the carbon dioxide react with water to form hydrogen carbonate molecule again after that?

[pulkit]

Its not exactly a reaction, its more of a dissolution. It can be confusing, because just like a reaction, this too involves an equilibrium as well as an enthalpy, entropy and volume changes.

[budullewraagh]

only 1% of CO2 dissolves in H2O and 1% of that forms H2CO3. it isn't a real molecule but rather it's the O2 from CO2 attracting an H2O molecule and separating it into H+ and OH- ions that float near the CO2 giving the impression of H2CO3.

[Chem-Maniac]

The acid HF tends more to get rid of its protons than HCl does, due to the higher electronegativity of the F-atom than of the Cl-atom.

[pulkit]

The acid HF tends more to get rid of its protons than HCl does, due to the higher electronegativity of the F-atom than of the Cl-atom.

 

HF is the least ionised of all hydrohalic acids though.

[budullewraagh]

here; i'll look up some statistics.

 

H-F bond delta [math]HF_2_5[/math] is 135.8

H-Cl bond delta [math]D_0[/math] is 102.3 give or take 0.1 (the measurement is similar to the HF2_5).

H-Br bond delta [math]HF_2_5[/math] is 87.5 give or take 0.1

H-I bond delta [math]HF_2_5[/math] is 71.3 give or take 0.1

H-At i couldn't find mainly because, essentially, At doesn't exist.

 

the bond between a higher halogen and hydrogen is stronger than that of a lower halogen and hydrogen, and so lower hydrohalides dissociate more than higher hydrohalides.

 

come to think of it i was quite stupid to look that information up when i could have looked up dissociation constants. oh well, here they are (note: these are all [math]pK_1[/math] values.

 

HF=3.18

HCl=-6.1

HBr=-9

HI=-9.5

[pulkit]

(note: these are all [MATH]pK_1[/MATH'] values.

 

These compounds will only have 1 [MATH]pK[/MATH] )

[budullewraagh]

that's another way of putting it

[SurfSciGuy]

Good stuff guys! makes you wonder what HI is like?

[budullewraagh]

in the same concentration, a little more acidic than hydrobromic

[Primarygun]

separating it into H+ and OH- ions that float near the CO2 giving the impression of H2CO3

Oh I see, that smells acidic.

How does the hydrogen ion in sodium hydrogencarbonate come out?

It seems to be very stable and inertly involve in the decomposition.

[budullewraagh]

the sodium and hydrogen cations dissociate when it is dissolved, just like with any ionic substance.