blogfast25 - 9-5-2008 at 06:12
I've been looking high and low to procure a few hundred gram (or even less) of Niobium pentoxide (Nb<sub>2</sub>O<sub>5</sub>,
aka Columbium pentoxide) for a couple of months now but no joy. Even Pyrochlore concentrate would be great but that's possibly even harder to find.
Niobium metal itself is easy enough to get but it's hard to convert into its (relatively few) compounds. Even more maddening is that I have a source
for the much rarer Tantalium pentoxide but have no use for it.
Any ideas, source of info would be much appreciated... And anyone willing to sell me some would be even better... 
-jeffB - 9-5-2008 at 07:05
Chemsavers on eBay lists it at $35 for 100g. If you're in the US, that ought to be practical...
blogfast25 - 9-5-2008 at 07:35
Hi JeffB,
Yes, that would be great but I can't find any listings for Niobium pentoxide (I also tried 'Niobium oxide') in eBay (I have a 'want it now' alert on
this type of item for quite some time now) and searching eBay shops that correspond to 'chemsavers' didn't yield anything either. Do you have an
eBay url on this?
Searching for 'chemsavers' in Google yields Chemsavers.com and searching inside:
Niobium oxide (with the correct CAS number) but at much higher price than $35/100 g. The latter price would be good!
[Edited on 9-5-2008 by blogfast25]
-jeffB - 9-5-2008 at 08:29
Sorry for the partial information earlier -- it didn't occur to me than an eBay search wouldn't do the right thing.
Try this URL:
http://search.stores.ebay.com/CHEMSAVERS-INC_niobium_W0QQfci...
Here's a direct link to the $35 auction:
http://cgi.ebay.com/Niobium-oxide-99-95-325-mesh-or-3-12mm-O...
Here's the link I get when I search for "niobium oxide":
http://search.ebay.com/search/search.dll?sofocus=bs&sbrf...
It includes two listings from Chemsavers, whose eBay storefront is at
http://stores.ebay.com/CHEMSAVERS-INC
That last link ought to work for you even if everything else fails. I wonder if you've set your eBay prefs to exclude results from eBay storefronts?
blogfast25 - 9-5-2008 at 08:47
Hi JeffB,
I can see what's been happening now: eBay automatically redirects me to ebay.co.uk (from my UK IP address) and Chemsavers do not ship internationally,
which explains why Chemsavers items do not appear as eBay.co.uk listings. The (eBay.com) urls you so kindly have produced work from my PC
without redirection, so there's hope.
Finding an American friend who'll ship it back to me isn't the problem but I'm not sure I'll be able to make a purchase from eBay.com rather
than from eBay.co.uk because of this redirection issue (but it'll easy enough to find out...)
Surprised too they offer this high grade material (99.95 % purity) at such a discounted price, compared to their catalogue price. 35 bucks plus
shipping is affordable (but it was never going to be a cheap material).
Still, it's all a lot of progress in a short space of time... Thanks! 
panziandi - 9-5-2008 at 12:03
Hey Chemsavers will send non hazardous chemicals internationally (to the UK) as I have had quotes for shipping before but it tends to edge on the dear
side.
[Edited on 9-5-2008 by panziandi]
The_Davster - 9-5-2008 at 17:40
If you have the metal and a furnace with appropriate crucible, niobium pentoxide is easy to make, the metal oxidizes very readily at around 800C in my
experience, in which a several inch long tube of niobium was reduced to powder overnight.
blogfast25 - 10-5-2008 at 05:50
panziandi:
Well, here it says "We do not ship internationally!" It doesn't get much firmer than that...
And here: "All orders are shipped within 7 business days of payment via DHL or FedEx Ground. Alaska and Hawaii excluded. Quotes are available for these two
location, [...]
But it's worth inquiring I guess...
{edit: I've just sent them an ebay email, so I'll know soon enough what's what...}
The_Davster:
Oxidation of pure Nb is a possibility I guess but mine is a simple charcoal fired furnace: to keep it going for prolonged periods of time is a pain.
But I've considered it as the metal is readily available and quite cheap too...
[Edited on 10-5-2008 by blogfast25]
panziandi - 10-5-2008 at 08:32
Well I had quotes given for non hazardous solids but as they were packaged in glass jars the price of airmail was quite a bit. Depends how desperate
you are. If you notice they sell many hazardous chemicals so it's easier perhaps to just say they don't ship internationally? try it anyway they alway
seemed to have a quick response.
DJF90 - 14-11-2008 at 12:58
If the niobium pentoxide is still needed theres 100g on ebay for £8 inc. p&p, Buy It Now.
http://cgi.ebay.co.uk/NIOBIUM-PENTOXIDE-High-grade-material-...
Oh look theres 5 available... 
[Edited on 14-11-2008 by DJF90]
blogfast25 - 15-11-2008 at 10:41
@ DJF90:
Thanks a lot for pointing that out to me. Despite having a "Wanted: niobium pentoxide" alert out on eBay for months now, no one has offered the
product to me yet, so this listing is most interesting to me...
The problem is that the seller in question is unresponsive to emails (I've sent a few in the past) and recently sold me a strange Manganese oxide,
claiming it was "High grade MnO2" (see relevant thread here), so my confidence in the seller has decreased a lot (again he was unresponsive to my query about the unusual oxide).
But I've taken the plunge and have ordered some Nb2O5 from said listing. All being well, homemade Niobium lump metal will soon be mine,
<i>mwuhahahaaa...</i>
[Edited on 15-11-2008 by blogfast25]
woelen - 15-11-2008 at 11:32
I also have ordered many chemicals from this seller in the past, and actually, my experiences are quite good. I have the following from him:
- Ta(OH)5
- WO3 (exceptional quality)
- Cr (good qualtiy, better than 99+ %)
- V2O5 (exceptional quality)
- SnO2
- MnO (my worst buy, contains a lot of iron)
- Fe3P
- Ni2B
I also have some non-eBay items from this guy. He offers more, but cannot sell that through eBay, due to toxicity and/or reactivity.
I think that you will have a good buy with the Nb2O5.
Btw, what kind of experiments do you have in mind with the Nb2O5? This stuff is very inert and hardly can be brough to a reaction. My Ta(OH)5 looks
nice (white powder), but I have not found anything which reacts with this stuff.
12AX7 - 15-11-2008 at 13:46
Thermite, of course. Let's see, half a year ago, that was right around the height of his KClO3-enhanced thermite researching, wasn't it? Titanium
seems to work; tantalum and niobium, much more difficult due to their melting points, would be quite an accomplishment.
Tim
blogfast25 - 15-11-2008 at 14:33
Tim:
Actually, the 'urgency' of purchasing Nb2O5 somewhat tailed off for me when it became apparent that the aluminothermic reduction of this oxide isn't
just feasible, it's actually used on large scale for the production of (relatively crude) niobium. That reduced the challenge somewhat...
For Nb2O5, the HoF is ΔH<sub>f</sub><sup>298 K</sup> = -1,831 kJ/mol, for Al2O3
ΔH<sub>f</sub><sup>298 K</sup> = -1,676 kJ/mol. The enthalpy of reaction for Nb2O5 + 10/3 Al ---> 2 Nb + 5/3 Al2O3 is
thus + 1831 - 5/3 x 1676 = -962 kJ/mol Nb2O5 reduced, a real whopper! Thermochemical calculation shows that is just about enough heat to heat
the 2 mol of Nb and 5/3 mol of Al2O3 past the MP of Nb (2,750 K), in adiabatic conditions. It should be very similar to my V2O5 thermites...
A bit of fluorite flux and minimum chlorate-boosting should do the trick. To be continued in the "thermite" thread, "shortly"...
For Ta (MP = 3,290 K (!!!)), it's a different story. Only Mg <i>might</i> work because the MP of Ta is higher than the BP of
alumina but I fear problems with magnesium metal's volatility. It's on my list of "things to try before I die..."
@Woelen:
Try driving off the water from the Ta(OH)5 by glowing and thermiting the resulting pentoxide with Mg powder. Reaction guaranteed but whether
you'll obtain lump Ta is another matter. If not, dissolving the slag (MgO) in strong acid should leave you with spherically powdered tantalum...
blogfast25 - 9-12-2008 at 08:53
First results of the Nb thermite are available on this thread of this forum.
Rosco Bodine - 10-12-2008 at 02:03
Actually niobium doping of titanium oxide and also
possibly spinels containing a niobium oxide component are of potential interest in perchlorate anode experiments.