Sciencemadness Discussion Board - Deadly Simple Liquid

Deadly Simple Liquid

Endimion17 - 10-4-2013 at 07:42

I've came upon a fantastic discovery few minutes ago. I had a hunch, made a hypothesis and when I turned on my equipment to test it, it proved right. I'm so happy right now.
Photos shortly. It will be a quiz.

OK, guys... I want you to guess the substance in this container. Let the background image be a slight hint. A very, very slight hint.

Each one has ten shots. You'll never guess.

EDIT(woelen): Split from pretty pictures thread

[Edited on 12-4-13 by woelen]

Adas - 10-4-2013 at 08:27

Is it acetic anhydride or some liquified gas?

Pok - 10-4-2013 at 10:04

Ultrapure White Phosphorus
Deuterium peroxide
A saturated solution of Scandium bromate
Liquified Octafluorocyclobutane
Decolorized urine from an agamid lizard - namely: Sitana ponticeriana

I'm sure it's one of these! I can see it from the refractive index! Too easy, man!

Endimion17 - 10-4-2013 at 11:23

Keep guessing.

<iframe sandbox width="420" height="315" src="http://www.youtube.com/embed/Q-xEiOPLbWA" frameborder="0" allowfullscreen></iframe>

It's something I've bought recently.

[Edited on 10-4-2013 by Endimion17]

Adas - 10-4-2013 at 11:35

Hmmm, maybe water?

Or pure coniine?

DraconicAcid - 10-4-2013 at 11:50

Ethyl acetate? Methyl acetate? Acetyl chloride? Molten sodium acetate?

Endimion17 - 10-4-2013 at 12:36

But it's not what it looks like therefore it can only be something that doesn't look like this.

It behaves like this (there are also hints on YouTube), but it does not look like this.

I know you're mad right now, but I rarely have a chance to create a decent riddle so play along.

The video description and the video itself might give you a clue. It's very hard, and I admit I probably couldn't answer it myself.

You'll be stunned once I give you the correct answer. As far as I know, nobody ever even mentioned this particular behavior of this thing online, let alone posted a video of it.

[Edited on 10-4-2013 by Endimion17]

DraconicAcid - 10-4-2013 at 12:37

Choline chloride/urea eutectic.

Simbani - 10-4-2013 at 12:45

Maybe just plain methanol?

Eddygp - 10-4-2013 at 12:55

hydrofluoric acid?

Adas - 10-4-2013 at 12:58

Liquified formaldehyde? Chloroacetic acid anhydrite? Chloral hydrate? Sulfur trioxide? Nitric oxide? Or possibly trialkyl aluminium?

[Edited on 10-4-2013 by Adas]

Mixell - 10-4-2013 at 13:02

carbon monoxide, carbon disulfide.
Carbon tetrachloride/bromide.
Some deriviation of plumbane/silane/stannane.
Some interhalogen compound.
Some halogen oxide.
Those were my 10 guesses.

Come on, don't keep us waiting.

Pyro - 10-4-2013 at 13:17

NG maybe? thionyl chloride?

kristofvagyok - 10-4-2013 at 13:52

"It can kill you"... I think that this could be also said from this too:

Finnnicus - 10-4-2013 at 17:51

Endimion you are a bad person

thionyl chloride? Triethylborane? Diphosphane?

Lambda-Eyde - 10-4-2013 at 18:32

Phosgene? I doubt it's a supercooled solid, but I wouldn't count it out just yet...

Endimion17 - 11-4-2013 at 04:45

The more you fail, the more happy you'll be this weekend (or tomorrow). Tee hee! XD

Today's hints are:
- it's not a liquefyed gas, nor a molten solid at room temperature; the pressure above the liquid is 1 atmosphere
- it fumes horribly when you open the container
- low boiling point, significantly lower than the boiling point of water
- rather heavy liquid
- it's not a mixture

And, as mentioned before, it's not what it looks like.

kristofvagyok - that's a bottle of joy and happiness right there, LOL.

This wouldn't kill you as fast, given the same molar content, but the suffering would be greater...

[Edited on 11-4-2013 by Endimion17]

Pok - 11-4-2013 at 05:37

Phosphorus trichloride

If you made any mistake with your hints we will be very angry! Is it organic? Say yes or no.

BTW: if it's not what it looks like then it isn't what the seller claimed it to be.

[Edited on 11-4-2013 by Pok]

Endimion17 - 11-4-2013 at 06:06

No, this is not PCl3, and I haven't made any mistakes so far.

I really shouldn't give off any general clues, but to reduce the number of chemicals involved in the riddle, let me just say it's very simple and inorganic.

BTW: if it's not what it looks like then it isn't what the seller claimed it to be.

You're dead wrong. Consider what Benjamin Franklin said about older women he chased a lot - all cats are grey in the dark.

Oh, the confusion.

Lambda-Eyde - 11-4-2013 at 07:09

SiCl<sub>4</sub>? TiCl<sub>4</sub>? POCl<sub>3</sub>?

Pok - 11-4-2013 at 07:18

No. It's not what it looks like.

Poo? It's highly toxic and corrosive. And "it's not what it looks like".

Tell it us! 24 h are the eternity in the internet. I am awake for 24 hours now and didn't go to work because I want to know it. Don't let me die from insomnia! This isn't funny anymore! It's a psycho WAR!

[Edited on 11-4-2013 by Pok]

Boron Trioxide - 11-4-2013 at 07:44

Well it could be N2O4 it is technically liquid at room temp, very reactive and volatile and dosn't at all look like what you have, possibly low light conditions obscure its colour?

I really like these puzzles they should be done more often.

[Edited on 11-4-2013 by Boron Trioxide]

Adas - 11-4-2013 at 07:54

Quote: Originally posted by Boron Trioxide

Well it could be N2O4 it is technically liquid at room temp, very reactive and volatile and dosn't at all look like what you have, possibly low light conditions obscure its colour?

I really like these puzzles they should be done more often.

[Edited on 11-4-2013 by Boron Trioxide]

N2O4 is blue when liquified. It might be SiCl4! This fumes heavily when exposed to air.

Endimion17 - 11-4-2013 at 08:06

No, no, no, no.

And poo? Fuck, I had no idea poo is corrosive... Well, technically, bird poo is, and human poo is certainly corrosive to potassium. I'm sure that, having a bench made of potassium and taking a dump on it would cause a lot more mess than just the fact there's poo on it.

Pok, although you've correctly understood it's not what it looks like (finally, someone), am so sorry, but you'll have to wait a bit longer. I've published an article to mess with even more people.

Go to bed. I'm sure nobody is going to guess while you're asleep.

Here's another hint. Look closely at the glass-liquid border. What do you see?

[Edited on 11-4-2013 by Endimion17]

Adas - 11-4-2013 at 08:44

Quote: Originally posted by Endimion17

Here's another hint. Look closely at the glass-liquid border. What do you see?

You mean the low viscosity? Because I don't see any glass-liquid border.

DraconicAcid - 11-4-2013 at 08:52

Corrosive, volatile, fumes....

Hydrogen fluoride, boron trifluoride, boron trichloride, fluoboric acid, methyl triflate, triflic acid, iodomethane....

dasgoose21 - 11-4-2013 at 09:24

Possibly oleum? If it fumes horribly, then this would fit because if pure SO3 Crystals were put in reagent grade H2SO4, then it could look like this, but still fit every description

ItalianChemist - 11-4-2013 at 11:17

Hydrochloric acid? Hydrogen cyanide?

[Edited on 11-4-2013 by ItalianChemist]

Pok - 11-4-2013 at 11:46

Almost every compound mentioned is colourless, transparent and liquid. This doesn't fit to the description. It has to be either solid or gaseous or coloured/opaque/white in it's usually known state.

It's bromine. Colourless bromine.

[Edited on 11-4-2013 by Pok]

chemcam - 11-4-2013 at 13:23

Well he said it is not a liquefied gas nor a molten solid so I am thinking it has to do with the color. Perhaps it is a fluorescent or phosphorescent liquid but under the lighting conditions it looks colorless.

Mixell - 11-4-2013 at 14:34

May be you have adjusted the lighting conditions so that it will appear colorless, when under normal lighting it has color?

So yea, it might be bromine or something of that sort.

Boron Trioxide - 11-4-2013 at 17:03

Fluoroantimonic acid

Perhaps it is liquid very pure white phosphourus in inert atmosphere, the melting point is supposed to be 44.2oC which could qualify.

Pyro - 11-4-2013 at 17:36

I thought of WP too. but it's boiling point, not MP.

[Edited on 12-4-2013 by Pyro]

neptunium - 11-4-2013 at 21:15

is it bromine ? under a funny wavelenght of light making it look transparent

yeah i am with Mixell on that one

[Edited on 12-4-2013 by neptunium]

[Edited on 12-4-2013 by neptunium]

woelen - 12-4-2013 at 01:17

I also go with mixell and neptunium. I have the impression that bromine does not absorb light at infrared frequencies (the tail of non-absorption extends a little in the visible range, hence the dark red color of bromine). So, if endimion17 has used an infrared camera or adjusted a normal camera by removing the IR-filter which is in many cameras, then I can imagine that he can make a movie and a picture like this.

Bromine is corrosive, toxic, gives dense fumes in air (not really fumes, but dense reddish gas) and if sufficiently pure and dry does not wet glass and has a high density (well over 3 grams per liter).

Your background picture is a slight hint. It shows a frequency range of 4000 waves per cm to 800 waves per cm. This is in the IR and far IR range (2500 nm for 4000 waves per cm to 12500 nm for 800 waves per cm). So, I consider this as extra evidence for my hypothesis that this is bromine imaged at IR wavelengths.

[Edited on 12-4-13 by woelen]

blogfast25 - 12-4-2013 at 04:18

I'd go with bromine too.

C'mon, Endi, you've had your fun! :mad:

Endimion17 - 12-4-2013 at 04:42

The winner is Pok.

Yes, it is bromine. I hoped no one will guess before I make another video, but it was kind of inevitable once people started talking about the properties other than "what you see".

So this is how it actually looks like.

In the video, I've blasted the sample with sunlight and then, by combining a two set of filters and a camera lacking a "hot mirror" (otherwise it won't work), removed everything but the >800nm range.
I often thought about this experiment, but I lacked equipment. Thanks to one guy ordering it for me, I was finally able to do it.

Talking about "colour" in the IR photos is futile. Although most photographers digitally enchance their photos, adding weird colors, it's not even black&white. It's like trying to describe a temperature of 25,000 °C.
Our sensory apparatus is useless outside its evolved ranges, so the simplest thing is to convert it grayscale.
In the 700-900 nm range, bromine is completely transparent. I was really stunned the first time I saw it, given the fact we're used to look at it as an optically extremely dense liquid. Also, to test a prediction made years ago was very satisfying.

woelen, you've really made a nice deduction there.

You're the only one who has recognized the infrared spectrum table behind. It was one of the clues. Nice work.

I've tested iodine, too. My hypothesis was that it would behave similar to bromine, but it turns out its melt is optically dense in this spectrum. It appears black. Maybe it's because its molecules are so large and prone to electron cloud distortions while bumping close together, I don't know. Maybe the range of transparency is shifted towards even greater wavelengths. I don't have the equipment to check it out.
What I predicted correctly is that its vapor is transparent. That nasty, thick vapor becomes invisible.
Now I'm in the range of making a small theory. If they're transparent in the gaseous phase, where the molecule interaction is poor, it might be that they're really distorting each other in the liquid phase, strongly attenuating pasing IR. Bromine is a lot smaller molecule, so this bumping doesn't distort it enough to affect its transparency in this wavelength range. I suppose liquid chlorine and fluorine would also be transparent.

What was interesting to watch is solid iodine. It is opaque (meaning black, in grayscale), but if you make highly ordered crystals, it is transparent. It's notoriously difficult to make a large monocrystal of iodine (it tends to make lots of differently positioned layers) so only the thinnest crystals look transparent. In transmitted visible light, iodine is pretty much like bromine, kind of red.

I'm making a video this afternoon, showing the transition for bromine, and I'll also test what happens with solid bromine. Something tells me it's going to be transparent because it crystallizes in large grains. I think it will look like ice slush.

The move after that is to record a nice, clean video of iodine melting, something previously impossible to me, because of the optically dense vapor in the visible range that makes dumb, uninterested teachers lie to kids about "iodine not having a melting point". Bromine also sublimes, but because its vapors aren't so dense, we see it melting.
I think these things should be more recognized because the worst thing in teaching science is this dull, unimaginative anthropocentric viewpoint. The goal should not be to relativize everything (that would be even more stupid), but to show why and when something is the way it is.

Anyway, people would've guessed it before if I haven't corrected the color of the IR shot. It was greenish, the tell tale of infrared shots.

[Edited on 12-4-2013 by Endimion17]

woelen - 12-4-2013 at 06:01

Very nice work. Beautiful to see that transparent liquid with the distorted image of the paper behind it, knowing that it is bromine.

This technique may also be very interesting to observe colorless or very weakly colored chemicals (e.g. gases), which cannot be seen in normal light with our eyes, but which may become visible as dense liquids or fumes in the IR-range. Lots of new possible experiments! Keep up the good work!

[Edited on 12-4-13 by woelen]

Finnnicus - 12-4-2013 at 06:08

Wow, wow, wow! That's really good reasearch there mate. Very excited for the iodine video. This was incredibly interesting, thanks. Could this effect be shown with non-halogens?

Pok - 12-4-2013 at 06:32

Really great! This may give us a small insight into the perception of e.g. animals that have a different range of wavelenght that can stimulate their nerve cells. For bees this would look similar (but maybe coloured). Bromine should be more transparent for them because they can see infrared light.

Endimion17 - 12-4-2013 at 06:59

Quote: Originally posted by woelen

Very nice work. Beautiful to see that transparent liquid with the distorted image of the paper behind it, knowing that it is bromine.

This technique may also be very interesting to observe colorless or very weakly colored chemicals (e.g. gases), which cannot be seen in normal light with our eyes, but which may become visible as dense liquids or fumes in the IR-range. Lots of new possible experiments! Keep up the good work!

[Edited on 12-4-13 by woelen]

Thanks. One of the things I've also tested is water. As predicted, is attenuates this range slightly, making a glass full of it look like there's a grayish, transparent substance inside.
Gaseous chlorine - completely transparent as predicted.

I've been thinking about the same experiments - making previously transparent stuff look opaque, but I can't think of anything at the moment that would be readily available outside my lab. Water vapor absorbs in even longer wavelengths...

If someone could test these things (and add some actual numbers to make it quantitative work) that would be great.

Quote: Originally posted by Finnnicus

Wow, wow, wow! That's really good reasearch there mate. Very excited for the iodine video. This was incredibly interesting, thanks. Could this effect be shown with non-halogens?

Yay!

Liquid oxygen absorbs in the red part of the spectrum, so it might look pretty opaque in this, NIR (or IR-A) spectrum. Unfortunatelly I can't test this.
Molten sulfur should be interesting, having all those colorful transitions, becoming deep red. It would probably glow, being that hot, but also probably semi-transparent. Like a glowstick, perhaps.

Quote: Originally posted by Pok

Really great! This may give us a small insight into the perception of e.g. animals that have a different range of wavelenght that can stimulate their nerve cells. For bees this would look similar (but maybe coloured). Bromine should be more transparent for them because they can see infrared light.

Insight, yes, but very small. We can find out whether they recognize the radiation, but their perception will probably be out of our league, forever.
Colour is an impression, a synthesis of inner workings of sensory organs and the central nervous system.
For example, people often talk about dogs seeing or not seeing some color. And they name it, thinking that the animal really sees what we see.
No one knows how do they perceive it. We might only say they recognize some wavelengths we perceive as green or whatever.

It's one of the things that makes me kind of sad. The number of wavelengths is infinite, and we only recognize few categories of color (and their tints). There are infinite colour impressions out there, and we'll never experience them.
Take a look at this funny comic.

Finnnicus - 12-4-2013 at 07:13

Liquid sulfur sounds awesome! How about metals? Or salts? Or am I misunderstanding?

blogfast25 - 12-4-2013 at 08:11

Yes, good work. I'm green with envy, truth be known!

Pok - 12-4-2013 at 08:21

Quote: Originally posted by Finnnicus

Liquid sulfur sounds awesome! How about metals? Or salts? Or am I misunderstanding?

No. Its possible. Silicon (metalloid) is transparent in the IR above 1100 nm or so. Endimion17, do you have silicon and can you achieve this (>1100 nm) ?

http://www.flickr.com/photos/imager/3380554807/lightbox/

Or IR-transparent germanium: http://www.youtube.com/watch?v=nzoq4WjnfVA from 0:55

Some salts do behave similar (e.g. thallium bromo iodide - KRS5, which is dark red transparent in reality).

[Edited on 12-4-2013 by Pok]

DraconicAcid - 12-4-2013 at 08:27

Quote: Originally posted by blogfast25

Yes, good work. I'm green with envy, truth be known!

I second that. I've often wondered/postulated what the world would look like to bees, butterflies (and fictitious species such as orcs and Klingons, who are also suggested to have different visual ranges), and I'd love to be able to take pictures at such wavelengths.

neptunium - 12-4-2013 at 08:33

everything looks very different in the IR spectrum...i have dark brown eyes in the visible spectrum but greish blue eyes in IR!
also the opposite is true ...transparent glass in visible wavelenght is completly opaque in IR....

fascinating ! thanks for putting this out and for the idea Endi..

Finnnicus - 12-4-2013 at 08:49

I'm not sure I understand (always learning), in the photo, red/bromine colored wavelengths have been removed? If this is true, does everything have a particular set of wavelengths associated with it?

Endimion17 - 12-4-2013 at 08:55

Quote: Originally posted by Finnnicus

Liquid sulfur sounds awesome! How about metals? Or salts? Or am I misunderstanding?

Metals should be completely opaque to any IR part because they're basically a cage of cations immersed in a gas made of electrons. Of course, if heated well enough, just as any other approximated black body, they will emit some of it. But that's emission, not transmission.
Some salts are definitely transparent and are made especially for this purpose. As Pok said, thallium compounds. Halogenides, even combined halogenides. I don't have any of them.

Quote: Originally posted by Pok

I don't have any germanium nor silicon to check it out.

However, not all IR is the same. I'm taking images in NIR, and "thermal cameras", the ones with psychodelic false colours, use lower frequencies. I don't have such camera. They're very expensive.

Quote: Originally posted by neptunium

everything looks very different in the IR spectrum...i have dark brown eyes in the visible spectrum but greish blue eyes in IR!
also the opposite is true ...transparent glass in visible wavelenght is completly opaque in IR....

fascinating ! thanks for putting this out and for the idea Endi..

No, just greyish.

There are no perceptible colours above deep red. Some cameras with "nightvision" give off greenish image, but I think that's just a simple way to help us see the details on the screen/goggles because eyes are most sensitive for yellow-green.

There are several confusing systems for categorizing IR, but to simplify, NIR crosses sodium and borosilicate glass without problems. My windows and test tubes are completely transparent to it.
Sodium glass is very opaque in the MIR-FIR (middle and far) range, which is completely out of my league.

Endimion17 - 12-4-2013 at 09:00

Quote: Originally posted by Finnnicus

I'm not sure I understand (always learning), in the photo, red/bromine colored wavelengths have been removed? If this is true, does everything have a particular set of wavelengths associated with it?

Bromine looks black because it absorbs pretty much everything. Even red is absorbed so strongly it takes a thin layer or very strong lightsource to shine through bromine.

It transmits the stuff below red quite well, such as near-infrared. So if you take a camera that registers NIR, and you shine NIR through the sample, and use a set of filters that block any visible light, it will appear transparent.

I've taken these photos this afternoon.

As you can see, bromine is completely transparent to NIR even when solid. It appears white (except the largest crystals) because of scattering, similar to any white compounds such as sodium chloride.
In visible light, bromine is deep red on transmission. Its molecules are ordered, so its overall transparency increases, although certain frequencies are efficiently removed (green, blue, etc.)

Just to add that, on reflection, bromine looks metallic. It's similar to iodine, basically.

[Edited on 12-4-2013 by Endimion17]

Finnnicus - 12-4-2013 at 09:07

Ah so it is really dependent on the substance, not how it looks. Bromine's behavior under NIR is somewhat unrelated to the evil red color?
Could this be done with mercury? Why/why not? How would I found out for myself?

12AX7 - 12-4-2013 at 09:10

Quote: Originally posted by Finnnicus

I'm not sure I understand (always learning), in the photo, red/bromine colored wavelengths have been removed? If this is true, does everything have a particular set of wavelengths associated with it?

Yes. Being made of electrons and quantum mechanics, photons can be absorbed when there's an allowed energy transition from the resting state (usually the lowest energy state, since room temperature isn't much energy to begin with).

Most insulators are transparent from DC to THz, and most conductors are opaque to reflective from DC to THz. At these frequencies, classical analysis suffices (electrical conductivity, dielectric constant, relative permeability, etc.).

At higher frequencies (far IR to UV), depending on the material, different things happen. Often, the change can still be expressed in a reasonable way in classical terms -- the waves are changing quite fast, so the electrons in the material exhibit phase shift, which causes loss or unusual phase shifts; modeling a dielectric as a capacitor, on its most reduced level (i.e., the material property of capacitance), breaks down and complicated substitutions take over. As the degrees of freedom go up, you pretty much have to resort to empirical data from which to construct your model, and the model value diminishes.

When you start talking materials with resonances, you're about as well off as using the quantum idea -- a resonance (an absorption or transmission line) relates to energy level transitions. Materials we think of as transparent are, of course, only transparent where we can see them; this occurs in insulators with a bandgap over 3eV. Lower bandgaps appear yellow, orange or reddish (try looking at the die in a green LED that has a clear lens), until the bandgap is so low that all incident visible light is simply reflected or absorbed. Silicon, with a bandgap of 1.1eV, appears shiny in visible light, but is transparent over the medium to far IR band. Quartz has a bandgap over 8eV, hence its used in UV lamps.

At even higher energies, atoms don't always act together; a UV or x-ray photon can strike the material and knock an electron out in a very quantum way. Photons of any energy are still waves, of course, so you can still set up experiments with diffraction and such (hence XRD and x-ray lenses, which are made using grazing angle optics).

Tim

12AX7 - 12-4-2013 at 09:15

And to bring that around to the present subject, bromine I suspect is something like liquid gallium arsenide: a semiconductor with a bandgap in the near IR (hence its use in ~900 nm LEDs and such), it looks black under visible light. Related alloys, like AlGaAsP, with incrementally higher bandgaps, look brown to reddish: red, orange and yellow LEDs are made of these materials. The reflection/absorption spectrum is probably very close to that of bromine.

The molecular density (for being a somewhat ionically bonded crystal) and index of refraction are probably higher for GaAs alloys than for Br, so they would tend to be exaggerated in darkness, blackness, and metallic luster, relative to Br.

Tim

Finnnicus - 12-4-2013 at 09:19

Tim, I know someday I'll understand. Today is not that day, thanks for trying.

Endimion17 - 12-4-2013 at 09:22

Quote: Originally posted by Finnnicus

Ah so it is really dependent on the substance, not how it looks. Bromine's behavior under NIR is somewhat unrelated to the evil red color?
Could this be done with mercury? Why/why not? How would I found out for myself?

The visible characteristics of a substance depend on the structure (chemical and physical), the radiation used to capture information, and the way we register transmitted, emitted and reflected radiation.

Its deep, evil red color is exactly like that - somewhat unrelated. It's merely a hint. There is no magical border between deep red and NIR in the reality, so it would be expected that absorption graphs don't just skyrocket right there.
There might be materials completely opaque to some NIR, yet transparent for frequencies we perceive as red.

Mercury is not only a metal, but a liquid metal. Electrons are responsible for the colors (their clouds affect photons), and as I've said, metals are cationic cages in electron gas. If you turn that cage into a mush, there's no way anything can get through. Mercury is black on transmittion. It has no color.
Mercury vapor, on the other hand, is atoms. I think it's transparent in any IR spectrum. It's transparent in visible spectrum, too, but it absorbs in UV-C, so you can shine it towards a screen that will glow in visible light when struck by UV-C photon, and put mercury vapor between, revealing a vapor casting shadow.

Finnnicus - 12-4-2013 at 09:27

That I understand, Tim is just out of my league hehe

DraconicAcid - 12-4-2013 at 09:30

Quote: Originally posted by Endimion17

Mercury is not only a metal, but a liquid metal. Electrons are responsible for the colors (their clouds affect photons), and as I've said, metals are cationic cages in electron gas. If you turn that cage into a mush, there's no way anything can get through. Mercury is black on transmittion. It has no color.

If you pound gold thin enough, you can pass light through it (I've read that it's green by transmission, but of course, it's not in the book where I thought I read it, so I can't give a reference). Could you squeeze mercury thin enough to get some light to pass through?

Endimion17 - 12-4-2013 at 09:38

Quote: Originally posted by DraconicAcid

Very thin metallic films are extreme cases cause it's just few cations thick. Yes, gold is greenish-blue on transmission, but that's probably because of its more complex orbital situation. When you include d-orbitals, you have a lot of work to do.

Aluminium does not have d-orbitals, so its films behave like extremely powerful neutral density filters. They attenuate all visible light, UV, NIR... Astronomers use them to stare at the Sun.

I have absolutely no idea what's the colour of mercury's thin films. I have tried to determine that few years ago, but without success. It would take more preparation than just sandwiching a tiny sphere between microscopic slides. I used great force and strong illumination, but nothing.
Perhaps a curved surface touching a flat one in one point would help.

[Edited on 12-4-2013 by Endimion17]

12AX7 - 12-4-2013 at 09:47

Protip: use a compact disc to look at the sun. The metallizing is very slightly transparent, with a bluish purpley transmission.

Not sure how you'd prepare a mercury layer... maybe you could make a flat capillary and bleed mercury into it? The strong surface tension precludes a single surface (it'll simply bead up!), and must make clamping two surfaces together nearly impossible. Might have better luck with a supercooled plate, depositing a layer of solid metal in vacuum (evaporation or sputtering, take your pick). Make sure it stays cool while you do your optical tests!

Lead might be a better candidate. I don't know how much difference you'd get between them...

Tim

garage chemist - 12-4-2013 at 09:57

Can you try this with benzene, or other condensed aromatic compounds like naphthalene and benzpyrene? Their absorption in the infrared should make these originally colorless compounds and their vapors look black. Perhaps you can then see black benzene fumes emanating from a beaker? That would be awesome.

Pok - 12-4-2013 at 10:52

Wohooo....I can confirm Endimion17's bromine photos!

I did it with a normal old digital camera with "night shot". It has an infrared diode.

Fantastic discovery, Endimion17!

Endimion17 - 12-4-2013 at 11:00

Awesome!

So sharp! My photos aren't very sharp because they're made by a camcorder (additionaly filtered).

Do you have any benzene lying around? I'd like to put garage chemist's idea to the test and I don't have it with me. Dark fumes would be ominous just as the compound is.

BTW that's one fine camera. Sony DSC V1. I like Sony's prosumer models, they have so much options you can play with.

@12AX7: Bluish transmission through a CD is not due to aluminium. There's something else inside. True aluminium layers, vacuum deposited, are just neutral density filters.

[Edited on 12-4-2013 by Endimion17]

Pok - 12-4-2013 at 11:05

Unfortunately I don't have benzene. It can be made at home in small quantities by heating sodium benzoate with NaOH. If nobody else has benzene and a nightshot camera I may try this at the weekend.

DraconicAcid - 12-4-2013 at 11:18

Do you have anything else that's aromatic? You could try sodium benzoate, or benzoic acid, or toluene, or similar things. I'm not sure what absorption you're looking for (my use of IR was restricted to the regular area of 1500 cm-1 to 3000 cm-1; if it didn't have a carbonyl or a hydroxyl, we weren't interested in it. This would be 3300 nm to 6700 nm, well away from the range of 700-900 nm mentioned earlier). Aromatics do absorb in the near-UV, though. Anyone have a camera that will take pictures in the 150-250 range?

Pok - 12-4-2013 at 11:46

I tried it with sodium benzoate. This is "white" with night shot. So no surprise.

Another chemistry site showed the "bromine effect" with a solution of methylene blue. I tried this and it works well:

Even with the bright light of the photo flash it's a nearly black solution, but in IR its totally transparent:

BTW you can see that the blue words on the paper also disappear ("www.pot......").

[Edited on 12-4-2013 by Pok]

DraconicAcid - 12-4-2013 at 11:53

Quote: Originally posted by Pok

I tried it with sodium benzoate. This is "white" with night shot. So no surprise.

Was that as a powder, or solution?

Quote:

Even with the bright light of the photo flash it's a nearly black solution, but in IR its totally transparent:

BTW you can see that the blue words on the paper also disappear ("www.pot......").

Extremely cool.

[Edited on 12-4-2013 by DraconicAcid]

Fantasma4500 - 12-4-2013 at 12:29

i would go with DHMO, but it has far too many victims for you to dare handling it (and i wouldnt advice it either!!)
but the background in the pictures says something with some organic stuff so its luckily not DHMO

woelen - 12-4-2013 at 12:43

This opens up a whole new range of experimenting. Maybe I'll buy myself an infrared camera. They are not dirt cheap, but for many people they are affordable.

Even normal cameras can be converted. Here someone offers a Canon A2200 converted to an IR camera and the buyer can tell what cut-off frequency he wants for filtering. E.g. 550 nm and longer wavelengths for golden yellow colors, or 800 nm for truly infrared only. If I were to buy something like this, then I would take the 800 nm filter which allows real IR photography.

http://www.ebay.nl/itm/Canon-A2200-14MP-Infrared-IR-Digital-...

blogfast25 - 12-4-2013 at 12:58

Mine has a 'Night Snapshot' option too ("Canon PowerShot A560 AiAf"), so I'll have to try something too. But I don't think it has an IR diode...

Now look what you've started, Endi!

[Edited on 12-4-2013 by blogfast25]

Endimion17 - 12-4-2013 at 13:23

Quote: Originally posted by woelen

This opens up a whole new range of experimenting. Maybe I'll buy myself an infrared camera. They are not dirt cheap, but for many people they are affordable.

Even normal cameras can be converted. Here someone offers a Canon A2200 converted to an IR camera and the buyer can tell what cut-off frequency he wants for filtering. E.g. 550 nm and longer wavelengths for golden yellow colors, or 800 nm for truly infrared only. If I were to buy something like this, then I would take the 800 nm filter which allows real IR photography.

http://www.ebay.nl/itm/Canon-A2200-14MP-Infrared-IR-Digital-...

Be careful, the sellers sometimes just want to get rid of a camera they've screwed up. It's basically a camera with hot mirror removed from the optical pathway.
However, if you don't use a filter, you get awful photos because IR bleeds pixels and fogs everything, and adds a weird tint. Once you remove the hot mirror, the camera is basically ruined for normal photos.
I used a camcorder which doesn't have that mirror and already has nighshot setting (it's purely mechanical), but the filtering is not very good, so I got the filter from this guy that sold me the bromine few months ago. It pretty much removes everything below 850 nanometres.
IR filters are usually sold in 700, 850 and 900 nm varieties, sometimes even 950... The point is they are pretty precise and you really need them for such photography. If you put them on any imaging device that isn't IR filtered, you can see the NIR image.
Buy 850nm or greater to get the best results.

This eBay seller lies when he says anyone can make gorgeus photos with this. IR photography is very difficult because the whole camera system isn't calibrated to those frequencies. There are huge problems with automatic and manual focusing, grain and deciding how to set up exposure, etc.

Quote: Originally posted by blogfast25

Mine has a 'Night Snapshot' option too ("Canon PowerShot A560 AiAf"), so I'll have to try something too. But I don't think it has an IR diode...

Now look what you've started, Endi!

[Edited on 12-4-2013 by blogfast25]

The problem with "nightshot"/"night snapshot" is that is receives way too much wavelengths. It is basically visible plus NIR, to get absolutely everything in dark situations.
Therefore if you don't add a very dense IR filter (don't bother with <850 nm), and you don't have an NIR radiation source, you'll see a white screen if you illuminate the samples with incadescent light or sunlight.

Yes, this is rolling, allright.

Eddygp - 12-4-2013 at 13:47

What about taking a night-shot of germanium, if any of you have some??? AFAIK it is transparent to IR light.

Pok - 12-4-2013 at 14:14

Germanium is transparent > 1.7 µm or so. I think that's to much for a digital camera. Silicon could be better. But something that should definitely work is cadmium telluride (black solid). This is transparent > ca. 850 nm. I tried it with gallium arsenide (transparent > 1.0 µm) but it isn't transparent for this camera.

Some examples for transmittance spectra of different materials: http://www.janis.com/Products/AccessoriesandAncillaryEquipme...

To see an effect the curve has to start between ca. 750 and maybe 950 nm.

[Edited on 12-4-2013 by Pok]

nezza - 13-4-2013 at 03:17

An interesting post. I'm a keen infra red photographer so I've had a go at bromine & a couple of other reagents. A concentrated iodine solution in potassium iodide is relatively clear, but chromyl chloride is still dark at IR wavelengths.

Eddygp - 13-4-2013 at 03:33

I would like to see something which is transparent in visible light but opaque in IR... or UV (glass)

[Edited on 13-4-2013 by Eddygp]

nezza - 13-4-2013 at 05:01

The obvious answer to that is a hot mirror. This looks pale blue-green to the naked eye, but is opaque to Infra Red. I dont know what the composition is though.

[Edited on 13-4-2013 by nezza]

Endimion17 - 13-4-2013 at 05:04

Quote: Originally posted by Eddygp

I would like to see something which is transparent in visible light but opaque in IR... or UV (glass)

[Edited on 13-4-2013 by Eddygp]

You have to specify which IR and which UV. They differ pretty much.
NIR, MIR, FIR, UVA, UVB, UVC, it's a wide whoice.

Borosilicate glassware is NIR-transparent but FIR-opaque (maybe even for MIR, I'm not sure). It's also semitransparent to UVA, but opaque to UVB and UVC.

NIR is "security cam IR" and the rest is in the domain of thermal imaging, so to say.

blogfast25 - 13-4-2013 at 05:15

Anyone tried an 'IR intensive' but VIS transparent aromatic compound yet?

Eddygp - 13-4-2013 at 06:30

Quote: Originally posted by Endimion17

Quote: Originally posted by Eddygp

I would like to see something which is transparent in visible light but opaque in IR... or UV (glass)

[Edited on 13-4-2013 by Eddygp]

I meant NIR and UVB.

Endimion17 - 16-4-2013 at 15:22

I'm uploading a new video. It will be ready in ten minutes or so.

<iframe sandbox width="420" height="315" src="http://www.youtube.com/embed/gvdMe4vtsIY" frameborder="0" allowfullscreen></iframe>

I just hope YouTube won't delete it because of the soundtrack...

Has anyone tried viewing NIR absorptive liquids using special equipment yet?

Endimion17 - 17-4-2013 at 06:22

As promised.

Iodine vapor is transparent, and liquid iodine is opaque. Solid iodine transparency depends on the degree of order in the crystals.
It's fun to watch it boiling on the screen when all you can see in the tube is blackness.
Video coming soon.

blogfast25 - 17-4-2013 at 09:07

I'm no expert on NIR spectroscopy but part of the of the I2 NIR absorbance must come from I2 as a quantum rotational (rotor) system, I think. Oh and these quantum harmonic oscillators too

I've put the video on my blog.

[Edited on 17-4-2013 by blogfast25]

unionised - 17-4-2013 at 12:05

Quote: Originally posted by Eddygp

I would like to see something which is transparent in visible light but opaque in IR... or UV (glass)

[Edited on 13-4-2013 by Eddygp]

Get a mirror.
To a bad, but interesting, approximation, the cornea of your eye meets those criteria.
Indeed, it's one of the factors that defines the ends of the visible spectrum (more so at the UV end, than the IR.)
the retina is sensitive to UV, but little reaches it because of absorbtion in transit through the eye: the proteins absorb it.
The IR is attenuated by water present in the eye and also by the proteins.
If you look at the spectum about two thirds of the way down this page
http://www.lsbu.ac.uk/water/vibrat.html
you can see that "visible" light is a pretty good match to the gap in water's absorbtion.

DraconicAcid - 17-4-2013 at 12:11

I've been told about a demo involving a UV lamp, a sheet of fluorescent TLC plate stuff, and a beaker of hot toluene. Mount the TLC plate on the wall, put the beaker under it, light it up with the UV lamp, and the invisible vapours from the toluene cast a visible shadow on the plate.

garage chemist - 17-4-2013 at 12:30

Forget what I said about the benzene and other aromatics- these absorb in the UV, not in the IR range of the spectrum!
I remembered this incorrectly. Benzene would most likely be as transparent in IR as in visible light.
Benzene vapor could be made visible by the same technique as for mercury vapor: between a UV light source and a fluorescent screen.

blogfast25 - 18-4-2013 at 04:47

Quote: Originally posted by garage chemist

Forget what I said about the benzene and other aromatics- these absorb in the UV, not in the IR range of the spectrum!
I remembered this incorrectly. Benzene would most likely be as transparent in IR as in visible light.
Benzene vapor could be made visible by the same technique as for mercury vapor: between a UV light source and a fluorescent screen.

Huh?

Benzene and aromatics do have strong absorbances in IR. Not sure what you mean here...