Sciencemadness Discussion Board - Iron (III) Carbonate

Iron (III) Carbonate

Megamarko94 - 6-5-2011 at 09:01

I've been trying to find information about Iron (III) Carbonate and i couldn't find anything..nothing on wikipedia,no msds nothing.
I think that the formula is "Fe2(CO3)3".
also is this reaction posible:
FeCl3aq+Na2CO3---->Fe2(CO3)3+NaCl
if you have any info on this supstance plz share.....

[Edited on 6-5-2011 by Megamarko94]

ScienceSquirrel - 6-5-2011 at 09:15

Try searching under ferric carbonate, it definitely exists and you can buy it;

http://www.chemicalbook.com/ChemicalProductProperty_EN_CB210...

It is a reddish powder that is insoluble in water. I suspect that making a sample that exactly fits your fomula is not easy and most samples are actually a basic compound.

Mixell - 6-5-2011 at 09:21

Na2CO3 in water form hydroxide anions too:
CO3 2- + 2H2O--> 2OH - + H2CO3 (decomposes immediately to water and carbon dioxide).
And FeCl3 hydrolyzes in water to form hydrogen chloride and some species of ferric oxo/hydroxo complex cations.
You will get a mix of Fe(OH)2, Fe(ii) and Fe(iii) carbonates ,ferric oxo hydroxides, complexes of iron in both of its oxidation states (for example Fe3O4, magnetite) and who knows what else.

The WiZard is In - 6-5-2011 at 09:32

Quote: Originally posted by Megamarko94

I've been trying to find information about Iron (III) Carbonate and i couldn't find anything..nothing on wikipedia,no msds nothing.
I think that the formula is "Fe2(CO3)3".
also is this reaction posible:
FeCl3aq+Na2CO3---->Fe2(CO3)3+NaCl
if you have any info on this supstance plz share.....

Your didn't do a very good job of searching! You would have
found that it iron carbonate doesn't exist. Iron subcarbonate
almost exists. It only took me a fraction of a second to find
how — in a book and on la Net.

djh
----
Queen Anne's Lace

According to folklore, the wild carrot (Daucus Carota)
was named for Anne of Bohemia, who married England's
Richard II in 1382. A ward of the queen, it seems,
chose this herb's delicate flower as a tatting pattern.
The little girl came to Anne's attention when she was found
innocent of a childish prank and the queen discovered
her pattern, which she liked so much that she gave the child
permission to name it after her. Queen Anne's lace was later
transferred to the wild carrot's flower and then to the
herb itself. The plant used to be valued as a diuretic and stimulant,
its relative the cultivated carrot botanically named Daucus Carota
sativa.

R Henderson
The Dictionary of Eponyms [Originally "Human Words" 1972]
Stein and Day 1985

blogfast25 - 6-5-2011 at 10:02

Quote: Originally posted by The WiZard is In

Hmmm… perhaps it’s you that didn’t do a great job of searching: ferrous carbonate does exist: see Siderite. And that can be made by combining a soluble ferrous salt with a soluble carbonate. Done that, been there...

But I’m surprised that there’s a ‘neutral’ ferric carbonate. I’d imagine it can’t be made by simply combining a ferric salt with a soluble carbonate because I think that would precipitate hydrated ferric oxide, not ferric carbonate.

Possibly freshly precipitated hydrated ferric oxide (Fe(OH)3.nH2O) is basic enough to absorb CO2 from the air (or another source)? Zr(OH)4.nH2O does that, somewhat unexpectedly.

[Edited on 6-5-2011 by blogfast25]

ItalianChemist - 6-5-2011 at 10:16

Quote: Originally posted by Mixell

Na2CO3 in water
You will get a mix of Fe(OH)2, Fe(ii) and Fe(iii) carbonates ,ferric oxo hydroxides, complexes of iron in both of its oxidation states (for example Fe3O4, magnetite) and who knows what else.

Fe(II) carbonate and hydroxide in water will soon become Fe(III)

[Edited on 6-5-2011 by ItalianChemist]

The WiZard is In - 6-5-2011 at 10:52

Quote: Originally posted by blogfast25

Hmmm… perhaps it’s you that didn’t do a great job of searching: ferrous carbonate does exist: see Siderite. And that can be made by combining a soluble ferrous salt with a soluble carbonate. Done that, been there...

If one defines a chemical as a pure substance iron
carbonate does not exist. Its composition is whatever the Gods
willed it to be when you last made it.

Sidererit Ye old Dana sez. Comp. Iron protocarbonate,
e.g., its a wanabe, not a pure substance.

If you react a solution of ferrous sulfate with sodium carbonate
you gets —

ferric carbonate
ferric hydroxide
ferrous hydroxide

In varying quantities together called iron subcarbonate,
iron oxide - brown, iron carbonate - precipitated.

So sez The Condensed Chemical Dictionary. 14th ed. p.618.

Something else for your it does not exist list — White chocolate.

-- I do not know why the quote is in bold, I did not do it, cannot
stop it. /djh/

blogfast25 - 6-5-2011 at 12:17

No, Wiz, 'sez' you. I disagree.

blogfast25 - 6-5-2011 at 12:19

Quote: Originally posted by ItalianChemist

Fe(II) carbonate and hydroxide in water will soon become Fe(III)

[Edited on 6-5-2011 by ItalianChemist]

Only in the presence of air. And even then, depending on conditions, only quite slowly.

[Edited on 6-5-2011 by blogfast25]

ItalianChemist - 6-5-2011 at 12:34

Quote: Originally posted by blogfast25

[rquote=209076&tid=16258&author=ItalianChemistFe(II) carbonate and hydroxide in water will soon become Fe(III)

[Edited on 6-5-2011 by ItalianChemist][/rquote]

Only in the presence of air. And even then, depending on conditions, only quite slowly.

Try to mix NaOH with FeSO4...green Iron(II) hydroxide precipitates.
Let the solution stand for a few seconds and the precipitate will become yellow-brown. In this case the oxidation is partial, but imagine that you have a very little quantity, the oxidation will be very fast.
Water contains also a little quantity of O2, so the oxidation takes places in absence of air.
To eliminate O2 simply boil the water!

ScienceSquirrel - 6-5-2011 at 12:36

Just because a material does not exist as a 100% pure substance that does not mean that it does not exist.
Sodium hypochlorite and sodium chlorite normally occur as solutions or as an impure solid but they are real compounds.
There are compounds like HCP that only exist for fleeting seconds at room temperature and are studied by spectroscopy. There are reactions intermediates that can be studied only by spectroscopy but they are real compounds.

blogfast25 - 6-5-2011 at 13:08

Quote: Originally posted by ScienceSquirrel

Just because a material does not exist as a 100% pure substance that does not mean that it does not exist..

Hear, hear...

blogfast25 - 6-5-2011 at 13:11

Quote: Originally posted by ItalianChemist

Let the solution stand for a few seconds and the precipitate will become yellow-brown. In this case the oxidation is partial, but imagine that you have a very little quantity, the oxidation will be very fast.

How long is a piece of string?

Megamarko94 - 6-5-2011 at 13:16

i tryed the reaction:
FeCl3+Na2CO3---->....
and thick brown precipitate formed...after filtering and drying...

ScienceSquirrel - 6-5-2011 at 13:44

Ferrous hydroxide and carbonate are oxygen sensitive but they could be prepared quite easily using air sensitive techniques, you could probably use carbon dioxide as the masking gas.
I suspect that reacting an iron III salt with sodium carbonate solution will produce iron III hydroxide with the carbonate being lost as carbon dioxide.

The WiZard is In - 6-5-2011 at 14:13

Quote: Originally posted by blogfast25

Quote: Originally posted by ScienceSquirrel

Just because a material does not exist as a 100% pure substance that does not mean that it does not exist..

Hear, hear...

Yes, however, if you define a chemical as a pure substance...

Can we settle on - it doesn't exist au natural?

Reminds me of Curry. There are to an infinitely large number
of Curry's, but NO Curry. Curry being in whatever proportion
you desire — coriander, turmeric, cumin, feungreek,
ginger, salt, black pepper, clove, celery seed, allspice, caraway,
mace and garlic.

Even some pure substances e.g., ammonium hydroxide don't exist.

The WiZard is In - 6-5-2011 at 14:57

Quote: Originally posted by blogfast25

Thank you for bringing up Siderite, it gives me reason to
pull one of my favorite books off the shelf — Deer, Howie and
Zussman's 1962, 5-volume - Rock Forming Minerals. They note
without reference - Volume 5 p. 274.

Siderite may be produced artificially by the reaction of
(HN4)2CO3 and FeCl2 at red heat, or by heating FeCl2
or FeSO4 solution with CaCO3 in a closed tube at about
200oC.

blogfast25 - 7-5-2011 at 06:57

Quote: Originally posted by Megamarko94

i tryed the reaction:
FeCl3+Na2CO3---->....
and thick brown precipitate formed...after filtering and drying...

Your thick brown precipitate is as SS and I suspect probably Fe(OH)3.nH2O, not Fe(III) carbonate…

But, but, but! There’s an easy way to find out. Especially since as you’ve gone to the trouble of somewhat purifying your product. Combined with any strong acid CO2 will be released, if carbonate is present: CO3(2-)(aq) + 2 H3O+(aq) === > CO2(g) + 3 H2O(l).

And by measuring the precise amount of CO2 for any given amount of carbonate you could even establish precise composition: Fe2(CO3)2 + acid === > Fe(III) salt + 3 CO2. Your 'Fe(III) carbonate' should dissolve effortlessly in any strong acid, with much effervescence. Small amounts of CO2 could be due to some residual Na2CO3 clinging to the product.

So ‘to fizz or not to fizz, that’s the question’…

[Edited on 7-5-2011 by blogfast25]

blogfast25 - 7-5-2011 at 07:03

Quote: Originally posted by The WiZard is In

Can we settle on - it doesn't exist au natural?

In the case of Siderite, I’m taking a hard line: natural FeCO3 may have been synthesised by geological processes we can’t reproduce in our labs (as is the case for many minerals) due to required forcing conditions. As far as minerals go Siderite (‘au natural’ or not) is a real a substance as any other.

I also bet that ‘synthetic Siderite’, carefully lab prepared, would show a composition that’s extremely close to FeCO3.

Megamarko94 - 7-5-2011 at 08:06

in effort to test unknown compound i put some of it in beaker and added HCl and CO2 was relesed...
and solution turned yellow the caracteristic color of FeCl3 and after some time small amount cristallize out...
And if iron (III) carbonate does exist then if heated should form iron oxide Fe2O3...!!!
Also if the cristals are FeCl3 is there some way to test it...???

blogfast25 - 7-5-2011 at 12:50

That would certainly seem to point to Fe2(CO3)3 but you need to be certain that the CO2 isn’t just a bit from Na2CO3 that wasn’t washed out of the product. Really the only way to prove you’ve got the Real McCoy is to measure the amount of CO2 evolved by a precisely known amount of product. 296.1 g (1 mol) of pure Fe2(CO3)3 would evolve 3 mol of CO2, about 67.2 l of gas at standard conditions…

Strongly heating Fe2(CO3)3 would also cause it to lose CO2, like you wrote…

Random - 8-5-2011 at 01:55

Quote: Originally posted by ScienceSquirrel

Ferrous hydroxide and carbonate are oxygen sensitive but they could be prepared quite easily using air sensitive techniques, you could probably use carbon dioxide as the masking gas.
I suspect that reacting an iron III salt with sodium carbonate solution will produce iron III hydroxide with the carbonate being lost as carbon dioxide.

I think I once prepared iron (ii) carbonate by mixing NaHCO and FeCl2. The precipitate was dark green almost black.

blogfast25 - 8-5-2011 at 08:11

Random: that's definitely the colour of 'synthetic siderite'.

My old Holleman has this to say about Fe (II) and Fe(III) carbonate in relation to the corrosion of iron metal:

'In moist air it [iron metal] rusts quickly, first Fe(HCO3)2 is formed, which by oxygen is quickly oxidised to iron (III) carbonate, which is transformed by hydrolysis to the hydroxide FeO₂H"

But that Holleman edition is two years older than myself...

White Yeti - 9-10-2011 at 16:05

I made this stuff not too long ago. I dissolve iron in vinegar, convert FeII to FeIII with H2O2. Precipitate the carbonate with NaHCO3, filter and dry. It's a brown powder and can be mustaken for rust. It turns into rust when heated on a hot plate, releasing carbon dioxide.

I was wondering why there is no Wiki page on this. It's too bad because it's really useful in making iron salts. Since it neutralises acids, you can dump some iron carbonate into any acid your heart desires to make the corresponding acid salt. I used the carbonate to make iron citrate. You can't make iron phosphate with it, sadly. Fun stuff.

blogfast25 - 10-10-2011 at 05:15

That sounds very interesting, WY, but are you sure it was Fe2(CO3)3? Not some basic carbonate or even plain Fe2O3? Ferric acetate is an interesting compound in its own right, so I might try that. Whether or not a carbonate forms with bicarbonate depends on the relative solubilities of ferric hydroxide and ferric (basic?) carbonate...

White Yeti - 10-10-2011 at 11:03

Quote: Originally posted by blogfast25

That sounds very interesting, WY, but are you sure it was Fe2(CO3)3? Not some basic carbonate or even plain Fe2O3? Ferric acetate is an interesting compound in its own right, so I might try that. Whether or not a carbonate forms with bicarbonate depends on the relative solubilities of ferric hydroxide and ferric (basic?) carbonate...

I tested the iron carbonate by dropping some of it into some lemon juice. As a control, I took iron oxide and dropped it into a separate container with lemon juice. The carbonate started fizzing and the oxide did nothing at all. Afterwards, the carbonate turned the lemon juice into this red brown liquid that remained brown after filtering, indicating the presence of iron(III) in solution.

I'm pretty sure I made iron carbonate, but I might be wrong. It's possible that I made a mixture of three separate compounds FeCO3, Fe2O3 and Fe2(CO3)3, instead of just Fe2(CO3)3.

You can duplicate the procedure and prove me wrong

seashell1982 - 29-6-2012 at 19:26

Quote: Originally posted by Megamarko94

FeCl3aq+Na2CO3---->

Was there ever any consensus as to what this reaction produced?

See Patent US 4657752

Perdurabo - 12-9-2012 at 13:16

. . to make ferrous carbonate. Uses FeCl2 and NaHCO3; claims high purity. Though this is Iron(II) and not Iron(III) carbonate

Poppy - 12-9-2012 at 15:36

What about careful decarboxylation of Iron citrate?

Poppy - 20-9-2012 at 15:32

Here are the pictures of the decarboxilation at 280°C of iron citrate I performed.
Its considerably paramagnetic, as evidenced by small ammounts of it sticking to a neodimium magnet.
It has a very distinctive odour identical to that of oil paint.
Iron carbonate is evidenced to be present as it weakly fizzles when added to acidic aqueous solution.

The reaction is odd, never heard of anything similar, guess it can be washed with a proper organic solvent to remove the soot chains or whatever it is sticking to the iron carbonate.

The reaction between Fe and citric acid was carried with iron III hydroxide, as it is easily soluble in acid, otherwise iron oxide didn't work for this.
The intentional reaction was
C3H5O(COO)3(3-)Fe --> heat --> FeCO3 + CO2 + 2H2O + 4C + H

Please see http://www.nature.com/nature/journal/v179/n4562/abs/179733a0...

[Edited on 9-20-2012 by Poppy]

plante1999 - 20-9-2012 at 17:11

Quote: Originally posted by Poppy

Here are the pictures of the decarboxilation at 280°C of iron citrate I performed.
Its considerably paramagnetic, as evidenced by small ammounts of it sticking to a neodimium magnet.
It has a very distinctive odour identical to that of oil paint.
Iron carbonate is evidenced to be present as it weakly fizzles when added to acidic aqueous solution.

The reaction is odd, never heard of anything similar, guess it can be washed with a proper organic solvent to remove the soot chains or whatever it is sticking to the iron carbonate.

The reaction between Fe and citric acid was carried with iron III hydroxide, as it is easily soluble in acid, otherwise iron oxide didn't work for this.
The intentional reaction was
C3H5O(COO)3(3-)Fe --> heat --> FeCO3 + CO2 + 2H2O + 4C + H

Please see http://www.nature.com/nature/journal/v179/n4562/abs/179733a0...

[Edited on 9-20-2012 by Poppy]

Your equation isn't properly balanced, there is only one ''atomic'' hydrogen in the product, please re balance it correctly so others can have a better idea of the reaction intended.

Poppy - 20-9-2012 at 17:40

My mistake!
Sorry for such incovenience also the iron II product is not even wanted, and I don't think it would form at an oxygen atmosphere at all!
Proper balance with additional oxygen source gives now the suspected reaction below.
About 30g citric acid where used to prepare this, to say, 0.156 mol citric acid put to react with an excess of iron III hydroxide aqueous gel and heated, finally comprising a 500mL solution.
Unreacted iron III oxide/hydroxide was filtered off, and probably has let iron make its path into oxides. I wouldn't admit a stoichometric reaction anyway.
Well, 0.156 mol Iron III hydroxide is 25g, which sums up up the citric acid to produce theoretically about 47g of anhydrous iron III citrate.

The measured mass of the decarboxylated product was 20g.
Considering the experimental yield to be 50 percent, thats roughly correct an assumption:
2 FeC6H5O7 + 13,5 O2 --> Fe2(CO3)3 + 9CO2 + 14H2O
It also agrees with the observation of the product being very fluffly and of a very low specific gravity, implying a lot of components must have escaped as gases. The oxydation was self catalysed by iron.

:cool:

blogfast25 - 21-9-2012 at 11:52

You have a lot more work to do before you can confidently claim you've synthesised ferric carbonate. For example, on calcining, what's the weight loss? Or by treatment with dilute strong acid how much CO2 do you get per gram of product? Are these results consistent with Fe2(CO3)3? Or is it a basic carbonate?

Poppy - 21-9-2012 at 15:04

I'm so excited about it. Verifying with CO2 release will be the ultimate test whatsoever.
Although it might be an easy route, its an expensive one, industrially.

Between if it is really the carbonate its worth consider the compound not so reactive as one would expect, alike Na2CO3.
I tested with nitric acid, which is not a good solvent for Fe or Fe2O3 anyway.

[Edited on 9-21-2012 by Poppy]

I did a preliminary test. I've put some of the powder into conc. hydrochloric acid, it fizzled, but such of a sort not much better than with nitric acid. I did it with so little powder I don't think it would give good results at all.
Anyone who deal't with CaCO3 and acid could give a tip on how long it takes to dissolve? It could be that Fe2(CO3)3 takes even longer to dissolve.
Even if the reaction didn't proceed too well from the decarboxylation at first, I'd put a bet: longer and hotter deal in the oven could probably do the job.

[Edited on 9-22-2012 by Poppy]

I came up the idea I'm pretty sure about : it may have become iron carbide thats why it doesn't reacts.

[Edited on 9-22-2012 by Poppy]

blogfast25 - 22-9-2012 at 13:43

Quote: Originally posted by Poppy

Between if it is really the carbonate its worth consider the compound not so reactive as one would expect, alike Na2CO3.

[Edited on 9-21-2012 by Poppy]

Anyone who deal't with CaCO3 and acid could give a tip on how long it takes to dissolve? It could be that Fe2(CO3)3 takes even longer to dissolve.

I came up the idea I'm pretty sure about : it may have become iron carbide thats why it doesn't reacts.

[Edited on 9-22-2012 by Poppy]

First point: various D-block element carbonates are all pretty reactive to acids.

Second point: how long it takes to dissolve depends on soooo many factors. But there’s no a priori reason why ferric carbonate would not react vigorously with dilute acids.

Third point: pray, tell, how?