the properties of lithium

[weldermanx]

hey i read somewhere that lithium can cause some really weird reactions that can purify metal oxides chlorides nitrates ... and so on. theres this reaction thats very strange its KNO3 + Li ---> LiNO3 + K is this possible? I heard its how some scientists purify a few unamed actinides. can anyone shed some light on this?

[YT2095]

it will indeed work under certain conditions, and it doesn`t behave "Weirdly" at all, it`s simple replacement.

[neo007]

something to do with it having a high charge density?

[EL]

something to do with it having a high charge density?

 

Absolutely correct.

[Primarygun]

KNO3 + Li ---> LiNO3 + K

In what reactions, lithium atom is more reactive than potassium atom.

[YT2095]

check the electro motive series, although lithium is less reactive as a material than say Potassium or Ceasium, it elctro motive potential is higher.

[Primarygun]

Yes. Yet, due to my current little,limited chemical knowledge, I hardly know one of these reactions.

[budullewraagh]

KNO3+Li-->LiNO3+K will not work, as the reduction potential of Li+ to Li is -3.040 eV/mol and K+ to K is -2.924

[Primarygun]

Doesn't it indicate that lithium lose e- more readily than potassium?

[rthmjohn]

I don't know if bud is right about this particular reaction, but more negative values for reduction-half reaction potentials mean that reduction is LESS favorable.

[neo007]

I don't know if bud is right about this particular reaction, but more negative values for reduction-half reaction potentials mean that reduction is LESS favorable.

 

Isn't that what he said?

[rthmjohn]

In fact it is. My mistake.

[neo007]

KNO3+Li-->LiNO3+K will not work, as the reduction potential of Li+ to Li is -3.040 eV/mol and K+ to K is -2.924

 

isn't -2.924 more positive than -3.040 ?

 

 

just read your reply john

[latentheat]

The more positive reduction potential will accept electrons (be reduced). So I don't see why this wouldn't work. And lithium is the most easily oxidized metal as far as I know.

[weldermanx]

sorry i wasnt responding because somebody was being a jackass... i know how the reaction goes, I just cant get it too work. Can anyone give me an idea of how to get these two unstable metals to react in a way they wont blow my face off?

[woelen]

KNO3+Li-->LiNO3+K will not work, as the reduction potential of Li+ to Li is -3.040 eV/mol and K+ to K is -2.924

I do not expect the reaction to work anyway, regardless of the precise redox potentials.

 

In order to have a reaction, the reactants need to be liquid, but at those elevated temperatures I expect the nitrate ion to act as a strong oxidizer towards the alkali metals.

Finely powdered Li + finely powdered KNO3 probably would be a potent pyrotechnic mixture .

[Primarygun]

In order to have a reaction, the reactants need to be liquid, but at those elevated temperatures .

KNO3+Li-->LiNO3+K

Having the reactants in molten state might be a good method, but I think the metal will react more readily with oxygen in air.

What's the readiness of O2 ---> O2- ? More readily than permanganate ion to manganese(II) ion?

 

I expect the nitrate ion to act as a strong oxidizer towards the alkali metals

Nitrate ion does not have reaction with hydroxide ion, right?

[woelen]

Having the reactants in molten state might be a good method' date=' but I think the metal will react more readily with oxygen in air.

What's the readiness of O2 ---> O2- ? More readily than permanganate ion to manganese(II) ion?[/quote']

Indeed, when one wants to make alkali metals, then one has to be sure that no oxygen can enter the reaction mixture. I do not see the relation with permanganate in this context, but I can assure you that reaction of hot molten alkali metals with oxygen is extremely easy and if oxygen enters the reaction mixture with molten alkali metal, then for sure, the metal will burn.

 

 

Nitrate ion does not have reaction with hydroxide ion, right?

Indeed, nitrate does not react with hydroxide, but... what is the relation with the topic on making K-metal from Li and KNO3?

[Primarygun]

Indeed, when one wants to make alkali metals, then one has to be sure that no oxygen can enter the reaction mixture. I do not see the relation with permanganate in this context, but I can assure you that reaction of hot molten alkali metals with oxygen is extremely easy and if oxygen enters the reaction mixture with molten alkali metal, then for sure, the metal will burn.

O^2- in aqueous solution is very unstable, right?

Indeed, nitrate does not react with hydroxide, but... what is the relation with the topic on making K-metal from Li and KNO3?

I thought, if you want to use nitrate ion in a solution, if you provide an alkaline condition, nitrate ion loses its oxidizing power.

[woelen]

O^2- in aqueous solution is very unstable' date=' right?

 

I thought, if you want to use nitrate ion in a solution, if you provide an alkaline condition, nitrate ion loses its oxidizing power.[/quote']

Sorry, but I'm lost. Are we still talking about making alkali metals?

If so, then please keep in mind that this cannot be done in solution. With 'liquid' I meant molten state, not dissolved in aquous solution. So, whether O(2-) is very unstable in aqueous solution (and yes, it is) or whether NO3(-) is not oxidizing in alkaline solution (and indeed, it isn't) does not matter at all, if we are dealing with making alkali metals like K. In water the only reaction you get is conversion to the metal hydroxide and hydrogen gas.

[rthmjohn]

The reaction might work... but you'll require molten lithium and potassium nitrate and will have to conduct the experiment in a vacuum. This is only possible in a dry box (or in outer space ), and good luck getting a hold of one.

[Primarygun]

Ya, the boiling point of lithium is quite high in this case.

You can just consider the b.p. of LiNO3 and KNO3.

[woelen]

The reaction might work... but you'll require molten lithium and potassium nitrate and will have to conduct the experiment in a vacuum. This is only possible in a dry box (or in outer space ), and good luck getting a hold of one.

What I tried to point out in previous posts is that I do not expect the reaction to work. The lithium most likely will be oxidized by the KNO3, not resulting in formation of K metal and LiNO3, but the nitrate ion will oxidize the Li with great violence.

If you have molten KNO3 and you throw in some reducible material then you get quite a violent reaction. Remember, KNO3 is a main component of black powder, which acts as oxidizer. As Li is even a stronger reductor, than C and/or S, expect the reaction between Li and KNO3 to be even more violent than the reaction between KNO3 and S+C, as in black powder.

[budullewraagh]

"I do not expect the reaction to work anyway, regardless of the precise redox potentials."

under proper conditions, it would work.

 

molten state is not to be considered, as KNO3 would just oxidize the Li (regardless of atmosphere), as mentioned above.

 

aqueous solution wouldn't work, as the water would just oxidize the Li.

 

HOWEVER. lithium is soluble in ammonia, ethylenediamine, aniline, etc.

due to the lone pair of electrons in trivalent nitrogen, primary amines and ammonia should be able to form a coordinate covalent bond with the potassium cation, so i would imagine that potassium nitrate would be at least slightly soluble in such solvents. in such conditions, the reaction would occur, and LiNO3 and K would be obtained.

[weldermanx]

yah i want the K but i had the problem of the lithium igniteing

i almost got it to work by boiling them in mineral spirits... the i think were starting to react because the litium started to turn to its normal silver tone and lose its oxide. but then the oil ignited and i ran for a fire extinguisher