Red iron oxide

[TATER]

hello, how do i tell whether a certain red powder is red iron oxide. I found a box full of red powder at a store which had household chemicals that people hadn't used. after careful reading of the box, i discovered that the powder was an oxide and couldnt figure out if it was iron. if anyone has any suggestions how to tell if it is iron oxide, that would be great

 

thanks

[Darkblade48]

Might there be some more labelling as to whether the stuff inside was indeed iron oxide?

 

Usually, things won't just be labelled so ambiguously (at least, they ought not to be!)

[CharonY]

X-ray diffractometry? ;P

Alternatively use a dye specific for iron (e.g. 2,2-diypridyl, ferrozine). You have to reduce it beforehand, though, as the dyes are Fe(II) specific.

This includes incubation with a potent reductant in an acidic solution.

[YT2095]

Fe2O3 is fairly inert, and even more so if it`s been calcined.

 

you could Try and dissolve some in acid, and then test with a Prussiate.

even a small trace of dissolved iron should show a blue color.

 

failing that make a small thermit mixture, ignite and then test the product with a magnet.

 

crude but effective

[kanzure]

X-ray diffractometry? ;P

Let's take that answer seriously. I have some information on x-ray diffractometry, so go there and search for "XRD". Some of the resources include a mailing list and some tutorials, but I have not found any designs/schematics for XRD machines.

 

- Bryan

[TATER]

what is a prussiate?

 

sorry, i just found one:potassium ferricyanide. right?

[CharonY]

Unfortunately you cannot easily build an x-ray diffractometre on your own. I got access to one, but it only works well if the sample is sufficently pure.

The question is what species of iron oxide it is. If it is darkish brown you may be in luck and it might be ferryhydrite.

This is readily soluble in HCl. However if you got goethite or hematite you either have to incubate it longer or heat it slightly to solubilize bits of it. Alternatively reduce it with hydroxylammoniumchlorid (Fe(II) is soluble) and then make a colorimetric assay.

In general, the darker the iron oxide is, the less crystalline it is. However, there are differences between iron(hydr)oxides.

[YT2095]

if it`s Red then it`s Fe2O3, black ish then it`ll be Fe3O4 and also magnetic.

 

Tater, yes Cyano ferrates are the prussiate, it`s the old way of making Ink for pens too, the blue is quite striking even with a trace, you`ll not miss it

[CharonY]

2-line Ferrihydrite is also blackish (with a slight brownish hue) like magnetite but it's non-magnetic. FeO(OH) (goethite) can range from yellow to reddish brown. After all there are around a dozen iron oxides and hydroxides around each with overlapping colour schemes.

Anyhow, prussian blue is a good way to find iron traces. However, if I recall correctly one has to be careful that it does not get oxidised as it might then react with itself. I think the pH had to be controlled or something like that.

[YT2095]

they can be destroyed in Basic conditions yes, but since there will be an acid used to dissolve a little of whatever maybe present that`s "Willing" to dissolve of the Fe2O3, there is no chance of it going Basic.

 

it is my opinion that in all probability that it`s a box of Jewelers Rouge (a polishing agent), it may even be Fake tan as used by some women during the war when they couldn`t afford stockings.

 

I think it`s likely a polishing agent though.

[TATER]

no, its a box of cement and tile dye. on the side of the box it states"this limeproof oxide is suitable for mortar, stucco, cement, water paints, shingle stain, etc."

[YT2095]

well Thanks for telling us all this NOW! *sheesh*

 

I never expected to be playing 20 Questions here!

 

anything of potential significance that you Could (should) have mentioned in post #1?

 

there, moved to a More Fitting area!