Fluorine and Gold

[Primarygun]

Is fluorine reactive enough to react with gold?

Regarding this reaction, does plastic have a higher tendency to react than gold?

[jdurg]

Seeing as how gold will react directly with chlorine gas, bromine gas, and iodine gas it's pretty likely that it will react with fluorine gas as well.

[ed84c]

HF wont react with Gold though with it? isnt aqua regia the only acid mix that will?

[DV8 2XL]

Gold will form two compounds with fluoride: AuF3 ( gold (III)

fluoride) and AuF5 (gold (V) fluoride.)

[jdurg]

HF wont react with Gold though with it? isnt aqua regia the only acid mix that will?

 

HF and F2 are two completely different compounds. HF doesn't oxidize much of anything, but F2 certainly does. The reason why aqua regia is able to dissolve gold is because while the nitric acid portion of it oxidizes the gold, the chloride ion is able to move in and stabilize the gold ion and pull it out of solution by forming AuCl4(-). This forces the equillibrium over to the right and allows more gold to dissolve. In HF there is nothing to oxidize the gold so it is unable to go into solution.

[Primarygun]

Besides Teflon and fluoride salts,

what kinds of substance do not react with fluorine?

[ed84c]

Most hydrocarbons dont i dont think.

[woelen]

Oh no, most hydrocarbons react explosively with F2 and they are broken down completely, forming CF4 and HF. If oxygen is present in them, that will form H2O.

 

The substances, with which fluorine does not react are fluorides in high oxidation states of metals, the alkali metal fluorides and the earth alkali metal fluorides.

[RyanJ]

Oh no' date=' most hydrocarbons react explosively with F2 and they are broken down completely, forming CF4 and HF. If oxygen is present in them, that will form H2O.

 

The substances, with which fluorine does not react are fluorides in high oxidation states of metals, the alkali metal fluorides and the earth alkali metal fluorides.[/quote']

 

So Fluorine reacts with pretty much everything then :S

 

What about the other rare metals such as Platinum and Rhodium?

 

Cheers,

 

Ryan Jones

[woelen]

Yes, fluorine reacts with all elements, except helium, neon, argon and krypton. It also reacts with virtually every compound, which is not yet fully fluorinated. There are a few exceptions, but these are rare. With some elements (e.g. the platinum metals) it only reacts very slowly, but even with these it reacts. When fluorine was made first at the end of the 19th century, a platinum anode was used. For each gram of fluorine produced, 6 grams of platinum were corroded away. You can imagine that the person who first made elemental fluorine must have been a wealthy person.

[budullewraagh]

sorry man, but krypton difluoride has been formed. also i thought i heard something about argon difluoride. i bet neon and even helium could react with fluorine at high enough pressure

[budullewraagh]

also, completely dry fluorine won't react with quartz, glass, or a host of silicon dioxide allotropes. and for that matter, i don't believe that dry fluorine reacts with a bunch of dry oxides, if any.

[woelen]

sorry man, but krypton difluoride has been formed. also i thought i heard something about argon difluoride. i bet neon and even helium could[/i'] react with fluorine at high enough pressure

Indeed, but did you also read the conditions, under which this is formed and what is needed to keep this stable? For any practical purpose, krypton does not form any compound, the lighter noble gases definitely are even less reactive.

 

Using special techniques, of course, one can make any compound, by placing atoms in an ultracold frozen argon matrix (T < 20K) and keeping them fixed in that matrix. But to my opinion this is cheating. Real chemical reactions at somewhat more common temperatures and normal storage conditions are not known for He, Ne, Ar and Kr.

 

also, completely dry fluorine won't react with quartz, glass, or a host of silicon dioxide allotropes. and for that matter, i don't believe that dry fluorine reacts with a bunch of dry oxides, if any.

You're right with this, but indeed, the fluorine and the quartz must be perfectly dry. Even trace amounts of water cause it to react. Also, there might be some refractory oxides, which are inert, even to fluorine, but these I place under the rare exeptions I mentioned.

[jdurg]

Indeed' date=' but did you also read the conditions, under which this is formed and what is needed to keep this stable? For any practical purpose, krypton does not form any compound, the lighter noble gases definitely are even less reactive.

 

Using special techniques, of course, one can make any compound, by placing atoms in an ultracold frozen argon matrix (T < 20K) and keeping them fixed in that matrix. But to my opinion this is cheating. Real chemical reactions at somewhat more common temperatures and normal storage conditions are not known for He, Ne, Ar and Kr.

 

 

You're right with this, but indeed, the fluorine and the quartz must be perfectly dry. Even trace amounts of water cause it to react. Also, there might be some refractory oxides, which are inert, even to fluorine, but these I place under the rare exeptions I mentioned.[/quote']

 

Kryton difluoride requires no special conditions or pressures. It's as valid a compound as the xenon fluorides are. It sublimes at about -60 Celsius which makes it very valid as a compound. (If it were a simple chemical matrix then it would not exist at room temperature). So krypton does form compounds woelen. I think it's argon that you are getting confused with. (As it's still up for debate whether the argon fluorides are actual transfers of electrons or simple atomic matrices).

 

Here's a link to some data on KrF2. (If it has a CAS number, it's a chemical). http://www.matweb.com/search/SpecificMaterial.asp?bassnum=EINOR0386

[woelen]

Jdurg, you're right . Althoug KrF2 is not the most stable compound, it definitely exists and can be stored as a chemical. I must have been confused with argon.

[jdurg]

Jdurg, you're right . Althoug KrF2 is not the most stable compound, it definitely exists and can be stored as a chemical. I must have been confused with argon.

 

No problem. Yesterday I was just on a 'DEATH TO ALL THOSE WHO DEFY ME' phase and was on some type of mission to stomp out even the slightest incorrect information. Yeah, it is argon that has only been created as a compound with fluorine at insanely low temperatures. There's still some debate as to whether or not transfer of electrons has actually happened, however. (I tend to consider any simplified arrangement of atoms involving two or more elements where electrons are transferred from one species to another a chemical compound). So if the Argon transferred electrons to Fluorine I would consider it a chemical compound no matter how unstable it is. I guess that's what the researchers are currently trying to find out.

[Primarygun]

also, completely dry fluorine won't react with quartz, glass, or a host of silicon dioxide allotropes. and for that matter, i don't believe that dry fluorine reacts with a bunch of dry oxides, if any.

Does this suggest that HF is more reactive than Fluorine?

[woelen]

Reactivity usually is defined towards another compound. When one says that a certain compound is ver y reactive, then it means that there are many other compounds, which react with it. More precisely, however, one has to state reactivity towards other compounds or classes of compounds.

 

In general, both HF and F2 are very reactive, but F2 can be regarded the more reactive. But there are compounds, for which HF is more reactive. It might be that indeed certain oxides and certain forms of glass or SiO2 are attacked more strongly by HF than by F2.

[jdurg]

Indeed. In fact, with glass the decomposition of the glass is caused not by the F2, but the presence of HF. Glass isn't just crystalline Silicon Dioxide. It's an amorphous mass of many oddly linked molecules. What causes the trouble with fluorine gas attacking glass is when an -OH portion of one of these molecules interacts with the fluorine gas. F2 will readily attack -OH groups ripping the -OH group off and in the process creating HF. HF attacks silicon dioxide without any problems. So when the F2 hits the glass, if there's any water in the air then it will form HF which will attack the glass. When HF attacks glass it creates compounds which have a readily available H atom exposed. F2 will then attack that H atom forming HF which repeats the process.

 

Theoretically, if you have glass made out of a single SiO2 crystal in a dry box with absolutely ZERO water molecules and 100% anhydrous F2, you could keep a sample of fluorine gas in a visible glass container. In reality, that's pretty difficult to do.