Sciencemadness Discussion Board

ferric chloride

carbon dioxide - 1-2-2005 at 10:28

what will happen if we add sodium chloride to a ferric chloride solution that reacts with copper?

JohnWW - 1-2-2005 at 14:01

The excess Cl- would result in the formation of the FeCl4- anion.

carbon dioxide - 1-2-2005 at 22:28

thanks

what will be the influence on the reaction between the ferreic chloride and the copper?

JohnWW - 2-2-2005 at 01:08

The reaction of FeCl4- with metallic copper was thoroughly thrashed out on a different thread on this forum some months ago, about August. In the presence of an oxidant, the mixture, in fact used for etching, can cause surface pitting/dissolution of the Cu as Cu(II), the Fe(III) acting (in my opinion at least) catalytically.

[Edited on 2-2-2005 by JohnWW]

tom haggen - 16-4-2005 at 13:20

would it be possible to syntheisize ferric chloride by this method?

FeNO3 + NaCO3 ---> NaNO3 +FeCO3

--> 2FeCO3 + 6HCl ---> 2FeCl3-H2O + 2CO2 + H20?

JohnWW - 16-4-2005 at 15:04

Some of the formulae in those equations are wrong. Fe(II) nitrate is Fe(NO3)2. Sodum carbonate is Na2CO3. To produce Fe(III) from Fe(II) requires the presence of a reactive moderate oxidant (but a too reactive one would result in Fe(VI))..

tom haggen - 16-4-2005 at 19:24

I'm pretty sure the store that sell ferric nitrate sells the Fe(NO3)3, I was having a really hard time finding a balanced equation. Is it even possible to synthesize FeCO3 from Fe(NO3)3?

No

chloric1 - 17-4-2005 at 07:39

Ferric ion is highly protonated. As soon as the pH of a ferric ion solution rises above about 3, hydroxy complexes begin to form and too much higher hydrated Ferric oxide separates from solution. Ferrous sulfate would yield ferrous carbonate a bluish-green precipitate exceedingly sensitive to air oxidation.

Oh yea as a little aside, I have a little over 400 grams of Ferric nitrate which is mostly a pale violet but has the brown crust of hydroxy complexes. When I want a clear solution of this salt I usually add 5 or so grams of HNO3 to get everything in solution. So sometimes ordinary exposure to moisture in the air causes hydrolysis of ferric salts.

[Edited on 4/17/2005 by chloric1]

tom haggen - 17-4-2005 at 09:37

Any idea on how to synthesize FeSO4-7H20? I assume it can be done with the regular; sulfuric acid + NO3 salt ----> HNO3 + sulfate salt. I tried balancing this equation and it was impossible.

[Edited on 17-4-2005 by tom haggen]

hodges - 17-4-2005 at 13:20

What is difficult about balancing the equation?

Fe(NO3)2 + H2SO4 ---> FeSO4 + 2HNO3

I think I misunderstood something about the question.

The_Davster - 17-4-2005 at 13:31

I think he was trying to balance
Fe(NO3)2 + H2SO4 ---> FeSO4.7H2O + HNO3 instead of the
Fe(NO3)2 + H2SO4 ---> FeSO4 + 2HNO3 and then
FeSO4 +7H2O --->FeSO4.7H2O

tom haggen - 17-4-2005 at 14:11

Yes I was trying to balance the FeSO4.7H20

So My reaction will go:

Fe(NO3)2 + H2SO4 ---> FeSO4 + 2HNO3

FeSO4 + 7H2O ----> FeSO4.7H20

FeSO4.7H2O + Na2CO3 ---> FeCO3 + Na2SO4 + 7H2O

2FeCO3 + 6HCl ---> 2FeCl3 + 2CO2 + 3H2 + O2?

[Edited on 17-4-2005 by tom haggen]

neutrino - 17-4-2005 at 14:15

The problem is that your iron goes from Fe (II) to Fe (III) in that last step.:P

tom haggen - 17-4-2005 at 14:32

Ok well the carbonate Ion is 2-,

So basically theres no way to get Ferric(III)Chloride from ferrous carbonate?

Well..yes

chloric1 - 17-4-2005 at 20:03

Yes there is..indirectly of coarse. You dissolve ferrous carbonate in HCl to get ferrous chloride then add H2O2 or bubble chlorine gas in. You could anode oxidize this ferrous chloride using a porous ceramic diaphragm and a graphite anode. Really you ahve several options open find out what you can on a search or a trip to the library.

cyclonite4 - 18-4-2005 at 06:27

You could always buy FeCl3 from electronics suppliers as an etchant.

Apparently it can be made by passing chlorine through glowing-red steel wool. Personally I would value Fe(NO3)3 more than FeCl3.

[Edited on 18-4-2005 by cyclonite4]

tom haggen - 18-4-2005 at 11:14

Ya I guess I wasn't aware that you could buy ferric chloride over the counter. I just know a store that sells technical grade Fe(NO3)3 and I was trying to get creative. I will look into purchasing it. I am still interested in ferrous carbonate though. Just out of curiousity would you use FeCl3 for etching circuit boards? So I know what to ask for...

Edit: I just figured out that it's sold at radio shack of all places.. Do you have any Idea what the oxidation state of The iron cation is in this over the counter product?

[Edited on 19-4-2005 by tom haggen]

cyclonite4 - 18-4-2005 at 18:26

Yes, it is used for etching circuit boards, and the oxidation state of Iron in FeCl3 is 3+ (Fe3+).

tom haggen - 18-4-2005 at 21:59

Yea I knew the oxidation state in Fe(III) was 3+ I just wasn't sure if they were selling FeCl2. Anyway, I'm still hell bent on synthesizing my own for fun.:P
Once I get some ferric nitrate and figure out the oxidation state of the Iron cation I will go from there, but that probably wont be for a while, I will post my results here.

[Edited on 19-4-2005 by tom haggen]

cyclonite4 - 18-4-2005 at 22:18

About your Iron (Ferric) Nitrate:
When the Iron cation is in the 2+ oxidation state, it is referred to as the Ferrous cation.
When the Iron cation is in the 3+ oxidation state, it is referred to as the Ferric cation.
Thus, if you say you have Ferric Nitrate, you have Iron (III) Nitrate, thus the oxidation state of Iron is 3+, which gives you Fe(NO3)3. So there is no need to physically determine what cation you have if you indeed know it is Ferric Nitrate.

tom haggen - 25-4-2005 at 17:17

Ok well I went to the surplus store and sure enough they were selling ferric nitrate. I was thinking about doing a reaction with sulfuric acid to get some ferric sulfate, and from there reacting and get ferric carbonate. However, I'm finding it very difficult to write a balanced reaction. Ferrous nitrate to ferrous sulfate is easy enough to balance since the oxidation state of iron is 2+ and every thing balances nicely. But the 3+ oxidation state of iron in ferric nitrate throughs every thing off. This brings me to my question. Is ferric sulfate even possible? If not what happens when your react ferric nitrate with sulfuric acid?

The_Davster - 25-4-2005 at 17:32

If it is possible it would go like:
2Fe(NO3)3 +3H2SO4 --> Fe2(SO4)3 +6HNO3

neutrino - 25-4-2005 at 18:58

The problem here is that you need something to react with Fe (III) to form Fe (II). Oxidation numbers don't just change by themselves. Adding solid iron ought to work here according to this equation:

2Fe<sup>3+</sup> + Fe -> 3Fe<sup>2+</sup>

cyclonite4 - 25-4-2005 at 21:47

neutrino, are you referring to the equation rogue chemist provided? If so, the oxidation state hasn't changed at all, its 3+ on both sides.

If the reaction works, I think it would be economical to make use of the nitric acid also produced.

tom haggen - 26-4-2005 at 07:51

Would this also work?

Fe2(SO4)3 + 3Na2CO3 --> Fe2(CO3)3 + 3Na2SO4

Fe2(CO3)3 + 6HCl ----> 2FeCl3 + 3H2O + 3CO2

neutrino - 26-4-2005 at 12:49

That should work.

Cyclonite: I was referring to tom’s unbalancable equations.

Archimede - 21-5-2005 at 19:09

My teacher was always getting mad when he saw chunks of alluminum in the ferric chloride we used to etch circuit boards.
I saw it for sale at radio shack but I didnt read the label to see what exactly its in the bottle.

Magpie - 1-3-2007 at 14:00

I've just gotten a pleasant surprise from the marketplace, for a change:

I bought 100g of photographic grade ferric chloride fully expecting it to be FeCl3*6H2O or FeCl3*4H2O. To my surprise it is very dark in color, appears red-purple in transmitted light, and is agressively hygroscopic. I have some sitting in a watchglass in front of me and within 15 minutes it has swelled up and changed color to light brown. It may well continue to lighten up to the hexahydrate which Wiki says is yellow.

The reason I am so happy is that it appears that I am now the proud owner of a Lewis acid. :D Can this be true?

woelen - 2-3-2007 at 01:26

Yep, it is true. You really have anhydrous FeCl3. I also have 100 grams of it (purchased as such) and it precisely matches the description you gave. Congratulations :).

12AX7 - 2-3-2007 at 08:10

Oddly, I checked on my baggie of ferric chloride hydrate and it's turned kind of green.

The bag, which I presume is LDPE, is amazingly permeable to the HCl vapor and seems to be changing mechanical properties. It's inside a PP pill bottle...

Tim

Magpie - 2-3-2007 at 10:54

Thank you Woelen for the confirmation. I have a feeling we have (or had) the same supplier. ;)

The FeCl3 on the watch glass continued to take up water until it was all in puddles. IIRC this is called deliquescence. Color had turned dark brown.

The original reason I bought the FeCl3 was to perform qualitative tests on organic compounds that I synthesize. My procedures for phenol and ethyl acetoacetate both called for this test. Its very sensitive. Just a drop of the organic in about 10mL water will turn pink or purple with 2 drops of 0.5M FeCl3.

I believe this test is specific for enols. I don't know the chemistry behind the test or what the colored products are. Perhaps someone on the board can tell me?

woelen - 2-3-2007 at 11:15

I had my ferric chloride from a German supplier, but I think the supplier you meant is a Canadian photography raw chemical supplier, and yes, I have purchased chemicals from that supplier also. Shipping, however, is quite expensive from there (at least, for me).

Ferric ions form a deep purple complex with phenolic compounds and a deep red complex with acetates and acetic acid.

IIRC the -OH group forms a complex with the iron (III) ion, I expect the lone pair of electrons on the O-atom to coordinate to the metal ion, just like water does. I have done the coordination experiments, and they work great for phenol, hydroquinone, catechol, acetic acid and acetates. They do not work for ethanol and methanol. Apparently, in the latter compounds, the lone pair of electrons in the O-atom is withdrawn too much. The coordination of the -OH group also does not work in thymol, although that is a phenolic compound. The latter probably is due to steric hindrance.

[Edited on 2-3-07 by woelen]

Magpie - 2-3-2007 at 12:04

Woelen: No my supplier is US. You stated in another thread that you used to buy from them but now they won't ship out-of-country. This is just more fallout from the War on Terror, I suppose. Too bad too, as they are cheap and ship lightning fast.

Yes, I believe I was incorrect in stating this test is enol specific. My old lab manual says it also tests positive for apha-hydroxy acids. And you have noted others. Forming coordination compounds with an oxygen lone pair does seem like a likely mechanism.

I tested purple for the phenol, and pink for the ethyl acetoacetate.