Experiments with UV-Light

[Mendelejev]

About a week ago, I bought a UV torch ! I know I can use it for my TLC plates and it would also be nice for some of my lanthanidesalts. Europiumsalts should emit red light, terbiumsalts green, and lutetium blew ! But i'm still searching for other fun experiments with UV-light. Maybe you could help me

[akcapr]

anything white will like glow

[blackout]

chloroacetic acid, pinacol...

[jdurg]

Uranium salts.

[YT2095]

Indian Tonic water (the sort use in Gin and Tonic). for some reason it`s perfectly clear like water in normal light, but seems to have an eery whiteish glow that looks cloudy under UV. maybe its the Quinine?

[H2SO4]

you can maybe try to excite some phospourus so it glows. I dont know if this can be done with UV though.

[H2SO4]

You should've boughten a 532nm green laser instead of a UV torch. Oh, i was curious, does it use UV led"s?

[Hephaestus]

blood, guts and proteins. Dont shine at any celebrity faces.

[Mendelejev]

You should've boughten a 532nm green laser instead of a UV torch. Oh, i was curious, does it use UV led"s?

 

It's the World SMALLEST Ultra Violet 12 UV LED Flashlight 1 AA

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5192580930

 

But now, you made me curious : why sould i've boughten a 532nm green laser ??

[YT2095]

actualy IIRC, there is a certain car magazine that was giving away a strip of about 6 UV leds as a dashboard illuminator it costs a fiver and should still be on sale

 

anyway, back to experiments:

 

get something fast growing like raddish seeds, plant about 5 seeds in each of 3 pots.

put one pot in ordinary sunlight, one in total darkness and another one in total darkness with only the UV light as a source, compare the results after a few weeks

[Mendelejev]

I just got my UV-torch. It's working quite good. The europium(III)oxide (white powder) turns red. But the color isn't so red. I was thinking, could I use a solvent for my europiumoxide that would cause the liquid to turn red ?? I know europiumoxide isn't soluble in water. But maybe in an organic solvent ?

 

Oh, and you see some purple light when the torch is on. It's quite annoying, becouse you see more purple than red. Could i use something (like a filter) to stop the purple light but not the UV light ???

[Hephaestus]

I have many variants of all the lanthanide salts in the cabinet in the office. I will let you know what colours I get under our UV light. Even though Europium Oxide is insoluble in water, it is not completely soluble. For fluorescence you need ver very dilute solutions anyway. Try adding a small amount of it to water, or to dilute nitric acid.

[Mendelejev]

I know that terbiumsalts should give a green color and thulliumsalt a blue color. But I don't think it works with the oxides of terbium and thullium. I tried it with my UV-lamp, but it didn't work. Europium(III)oxide (white salt) turned red, but not sooo red. Maybe becouse it's an oxide, and not a complex with big organic ligands that absorb the UV light and give their energy to the europiumcation.

 

I'll try tonight to add a small amount of my europiumoxide into some water or dilute HNO3. I'll tell you my results.

 

Oh would it be possible to change the europiumoxide into a europiumsalt that emits more and brighter red light ? Some kind of simple reaction with the oxide ?

[akcapr]

id assume u could react it with an acid- that is if the europium oxide bacome a base in water.

[budullewraagh]

it wouldn't. and it would be a little difficult to convert it to a salt. perhaps you could try complexing it to form an europate? but then again, i dont know this is possible. works with aluminum though.

 

perhaps:

2NaOH+Eu2O3+3H2O --> 2NaEu(OH)4

[Hephaestus]

*EuCl3, EuCl2 are much more soluble than the oxide. EuSO4 is sparingly soluble but commonly used to make other salts.

 

Prep for chlorides and sulfates below. If you dont know what a reducer or amalgam are then you shouldnt be doing this chemistry. Amalgam is very toxic and I would only dispose of waste with the university.

 

Eu2O3 + 6HCl = 2EuCl3 + 3H2O

2EuCl3 + Zn = 2EuCl2 + ZnCl2

EuCl2 + H2SO4 = EuSO4 + 2HCl

3.5g of Eu2O3 is soluble in 5.4 mL of 6M HCl to make EuCl3.

Dilute this to 200 mL. Fill a Jones reductor with 1% Zn amalgam which are washed with 200 mL of 0.1M HCl. Dip the outlet of the reactor in 50 mL of 8M H2SO4 in a 600 mL beaker covered with paper. Expel air from the beaker with CO2. Pass EuCl3 slowly (2 mL/min) through the reductor. Follow with 150 mL of 0.1M HCl.

Obtain light, white, hairlike crystals of unstable alpha-EuSO4. Heat this mixture to 80C in CO2 atmosphere to get stable dense crystalline beta-EuSO4 mass. Now stable under air.

Filter and wash with few mLs of HCl-acidified MeOH and dry at 75C.

[olmpiad]

Is it a Longwave or Shortwave UV light?

[Tetrahedrite]

Calcium tungstate (scheelite) and calcium molybdate (powellite) are classics when it comes to fluorescence (sp?). Many natural fluorites (CaF2) are also fluorescent and give brilliant colours under UV light.

 

The most famous fluorescent mineral locality in the world is Franklin, New Jersey, and anyone interest in fluorescence should take a look at the pictures on this page and also this page for a start.

[woelen]

Many oxides are remarkably inert, once they are calcined. I have some praseodymium oxide Pr2O3 (lightgreen powder), which does not dissolve in hot conc. HCl, not even in hot conc. H2SO4, nor in HNO3. Dilute acids also do not work!

 

I also have Cr2O3, TiO2, and SnO2 and these oxides behave similarly, no dissolving at all. I also have calcined Fe2O3 and Co3O4 and these oxides only dissolve at a mg per day rate in concentrated HCl. Really annoying...

 

I'm afread Mendelejev's oxides also will be VERY inert.

 

For making the salts of the lanthanides I have switched to the metals as starting point (currently Pr and Er, but I also want to experiment with Dy and Sm), the oxides simply are too inert to be useful.

 

 

If you want a really beautiful fluorescence, then use the dye fluorescein or its sodium salt, sodium fluorescienate. The solutions of these compounds are orange, but even on a cloudy day, the liquids give an amazing intense lime-green light. If you put the liquids in a ray of sunlight, then the entire beaker emits a lot of green light. Imagine what your UV-LED's will do with this!

[raivo]

Cr2O3 can be made soluble (converted to sodium chromate) by fusing it with NaOH especially if some oxidiser (like KNO3 or NaNO3) is added. Maybe this works with other oxides too?