chief - 9-3-2009 at 07:59
Since the BaFeO4-preparation is common among chembooks, and the BaFeO4 has some advantageous dielectric constant, one might have the idea to use this
to make some nice capacitors ... ...
Anyone tried this ? As I understand the dielectric contant varies with frequency, but it usually is given in the 1000's (water has 80), so building a
leyden-bottle with such dielectric might still result in a strangely high capacitance (and dangerous in the high-voltage-case) ...
[Edited on 9-3-2009 by chief]
WaveFront - 9-3-2009 at 13:05
Maybe it would be practical if you could make thin film with that material or use as aditive for the film(?).
By the way, BaFO4 should be a good oxydizer, isn't it?
[Edited on 9-3-2009 by WaveFront]
indigofuzzy - 9-3-2009 at 13:18
Not to sound foolish, but do you mean BaSO4?
I ask because BaFO4 seems unlikely. IIRC, Fluorine doesn't from FO4- or similar oxoanions, and Ba with F- and O2- would require Ba to be in the +9
oxidation state.
Even Ba(FO)4 seems unlikely - Ba(OF)2 (Barium Hypoflourite) I could see, but with two hypofluorites, not 4...
I'm confused.
chief - 9-3-2009 at 13:35
I made a stupid mistake above: I talk about BaFeO4, the ferrate ... (I'm gonna try to correct it now)
indigofuzzy - 9-3-2009 at 22:07
Nice job editing 
Thanks for clearing up the confusion.
Swede - 21-4-2009 at 06:10
Soak paper in the dielectric, and roll mylar or aluminum foil as a sandwich... 2 paper and 2 foil. Insert into a tube.
That's about all I know about making a capacitor! 
sakshaug007 - 21-4-2009 at 09:38
You could also try making a sol-gel using Ba(NO3)2 and Fe(NO3)3 precursors dissolved in a 5M citric acid solution then dip coat a material and calcine
to produce the BaFe2O4 ceramic film.
We use a similar procedure where I work to produce multi metal oxides i.e. BaxSryCa1-x-yTiO3.
JohnWW - 24-4-2009 at 04:28
Ba(FeO2)2 as prepared above would be barium ferrite(III). However, because of the likelihood of unutilized 3d electrons on the Fe entering the
conduction band, resulting in conductivity, and of Fe-Fe delta-bonding, it would probably not be a dielectric, unlike BaTiO3. It would probably be a
semiconductor. BaFeO4 is barium ferrate(VI), with some properties superficially like BaSO4 such as crystal structure and being very insoluble; but it
is quite strongly oxidizing, comparably to permanganate(VII), and liable to decompose on heating. (BTW Fe(VII) as FeO4- and (VIII) as FeO4 are
theoretically possible, and just might be obtainable by electrolysis of cold alkaline solutions of the ferrate, but do not seem to have been
reported).
The_Davster - 24-4-2009 at 06:09
A bit of work but...Perhaps if you could make/get volatile barium and iron compounds you could improvise a CVD setup and expose some heated aluminum
foil to the volatile precursors.
Mind you, volatile barium compounds do not sound like fun. And this would take a lot of fiddling to get the correct stoichiometry.
sakshaug007's solgel idea also seems workable, and I have done extensive Mn solgel work, and they always seem to increase oxidation state during the
process, so the Fe3+ used may indeed be oxidized under said conditions to give the desired ferrate. The OH termination of the thin oxide layer on
aluminum foil may make Al foil a suitable substrate.
Sedit - 24-4-2009 at 22:35
How thin could this material be layed out and how well would it compare to Mica?
I have made a TEA laser a while ago and the DE for these just sucks, no matter what you make it of. For this reason I don'use it much. With a
dielectric strength of 1000 I think alot of use could be made from this material under one condition.... What is its inductance/thickness value? Will
this be able to propagate a charge within 2ns or less?