formallydehyde
Harmless
Posts: 5
Registered: 6-4-2020
Member Is Offline
|
|
Synthesizing YInMn Blue in my kitchen, and breaking antique equipment in the process
Hey everyone, this is my first post here so sorry if this is the wrong place or something.
Some background
I've been really interested in inorganic pigments over the last few months and there's one that really caught my eye called YInMn Blue. The pigment
has an interesting story: In 2009 a (then) graduate student named Andrew Smith was researching potential electronics materials by mixing metal oxides
and roasting them at ~1200°C. One of the mixtures tried was Manganese(III) oxide, Indium(III) oxide and Yttrium(III) oxide, which turned vivid blue
after firing. It ended up being useless for its intended purpose but had excellent potential as a pigment. It also has some unique properties compared
to other blue pigments, like high near infrared reflection. It was billed as the first stable, inorganic, blue pigment that had been discovered since
Cobalt Blue in the early 1800s. Also, unlike Cobalt Blue, YInMn Blue is probably not particularly toxic or carcinogenic.
(I say probably here because as far as I know that assumption is based on its constituent chemicals, not on any actual toxicity data.)
I really wanted to get my hands on some YInMn Blue powder to grind with linseed oil to make oil paint, basically because I thought it would be neat.
This proved to be a lot harder than I'd hoped, few companies work with it because indium is a rare earth metal so it's way too expensive on an
industrial scale for most applications and it's generally difficult to come by as an individual consumer. Its lack of easy availability made it go
from "neat" to "forbidden fruit," and I became a little obsessed with the idea of making it myself.
Materials
I purchased everything on eBay from various sellers, I've linked the sellers for the chemicals themselves.
Yttrium(III) oxide came from this seller.
Indium(III) oxide came from Upstate Scientific
I wasn't actually able to find Manganese(III) oxide on eBay. I just purchased Manganese dioxide from Loudwolf. I know that's the IV oxidation state but at >500°C it decomposes into Manganese(III) oxide, I hoped that would happen pretty quickly
and it would end up getting stabilized in the 3+ state by the other ions before decomposing further.
Heating was a challenge, I live in an apartment and I think my landlord would complain if I was hitting things with a blowtorch in the courtyard. I
needed something that could go up to >1000°C, so I got a very old Kerr dental inlay furnace (No.2) for $100 US. I've nicknamed this furnace "Ol'
Terrifying." The wiring was nasty looking and when I put the plug into an outlet, the plug heated up after a few minutes. I initially wanted to rewire
it, but all the wiring ran into this wad of fabric behind the temperature dial. I am almost certain this fabric is asbestos and I really didn't want
to mess with it. This presented a problem, since it would need to be fired for several hours, the lowest time I saw in any of the original papers was
6 hours. My solution to this was to split each hour into 45 minutes plugged in/15 minutes unplugged. I also wrapped some aluminum foil around the
outside of the door to prevent heat leakage during the rest period, because Ol' Terrifying leaves a small gap even when the door's shut. I put it on
top of some insulating kiln bricks to try to protect my countertop from the heat. Antique dental inlay furnaces seem common on eBay but I really don't
recommend them for anything.
I needed crucibles and I didn't want to use graphite or iron because I was afraid of them contaminating the final product, and glass would just melt.
I ended up with a pack of adorably tiny, 10 mL Coors brand porcelain crucibles that I was able to get for really cheap. The small size also meant
there would be no issue fitting them in the cramped firing area of an inlay furnace.
I bought two 125 mL porcelain mortar and pestles, hoping I could just stick them in the furnace without transferring the powder into crucibles but
they were definitely too large. I got two in case one was sacrificed to the Chemistry Gods and forever stained blue, but I actually ended up receiving
five total mortar and pestles in the end, for reasons.
Methods
The generalized formula for YInMn Blue is YIn1-xMnxO3. The more manganese added, the darker the pigment is. I wanted
a sort of "standard" blue color to use for painting so I chose a manganese ratio of 0.2, which supposedly results in a nice medium blue pigment, about
the same intensity as Cobalt Blue. So the ratio ended up as YIn0.8Mn0.2O3. I combined 11.3 g Yttrium(III) oxide (0.05
mol) 11.1 g Indium(III) oxide (0.04 mol) and 1.7 g Manganese dioxide (0.02 mol) into an empty prescription pill bottle and shook it a lot with the cap
on, to get everything well mixed before grinding, with the idea I wouldn't have to worry about individual oxides clinging to the walls, and making the
mixture uneven.
The mix was dumped into a mortar and pestle and I ground it for quite a while, a bit past the point after I stopped feeling grit under the pestle. The
indium and yttrium oxide powders were pretty fine before even combining them, but the manganese dioxide was in tiny granules which were a pain to
grind and I think the other oxides were kind of cushioning the grains. In retrospect I might have saved a bit of hassle if I ground the manganese
dioxide up beforehand. Anyway, I used a plastic straw to scrape some of the powder into a crucible. I tamped the powder down as much as I could with
the pestle, and put the crucible in Ol' Terrifying. I made sure my kitchen window was open and a fan was blowing air outside so I wouldn't inhale any
fumes the furnace (or the oxide mix) might be giving off.
My initial idea was to roast it for 6 hours, using the cycling I mentioned earlier. But, after the third hour Ol' Terrifying was radiating a
lot of heat and the air smelled a bit ozone-y so I decided 4 hours was where I would call it, and hope for the best. However, when I went to
unplug it after 4 hours, the area around it was suspiciously cool and on investigation, Ol' Terrifying refused to power up ever again. The crucible
had some soot on the lid, which I think might have been from the smoke of whatever shorted/overheated. RIP Ol' Terrifying, 19XX-2020. I actually had
split up the ground powder into a dry ground fraction and a fraction that was ground with a bit of distilled water because I wanted to see if I would
get a quality difference between wet and dry grinding. The wet ground preps are just sitting around now, because I have no way to fire them.
Given how much it had cooled down, I think Ol' Terrifying failed at some point after 2-3 hours and didn't actually make it anywhere near the 4 hour
mark. That, combined with the soot didn't make me excited about my prospects for a quality product, but when I got the lid off of the crucible I was
pleasantly surprised by a nice vibrant blue color. I had to see if this was all the way through the sample or if I was just seeing a crust. The fired
sample had become pretty solid so I scraped it out into a mortar with the help of some water to soften the powder a little. I ground this up, adding a
little more water to help break up the solid chunks. Again, I was pleasantly surprised when it became clear it was homogeneously blue. I dried all the
water out of it in my normal oven at ~93°C in my normal oven for a few hours, and once I didn't see any more water I brought the temperature up to
~260°C for a few minutes to make sure it was all dry, then turned off the oven and just let it cool down in there overnight. I'm actually grinding
the final product with some linseed oil and a small amount of odorless mineral spirits over the course of today (and maybe tomorrow) to make some oil
paint out of it.
Final thoughts
Anyway, thanks for reading! This has been a fun project and despite the death of Ol' Terrifying, I think it was relatively successful. I'm quite happy
with the color also. Compared to my Cobalt Blue paint (which I have a lot of) it's got a nice warm tone, a bit more towards indigo than solid blue,
which I think is more obvious in person than in pictures because for some reason digital cameras seem to have a hard time with blues that contain
slight red tints. Hopefully sometime soon I will find a way to fire those other samples. The lab that found YInMn blue has apparently identified other
pigments by adding additional metal ions to the crystal structure, and I might try one of those with the bit of indium oxide I have left.
Additional reading
Smith, A., Mizoguchi, H., Delaney, K., Spaldin, N., Sleight, A. and Subramanian, M., 2009. Mn3+in Trigonal Bipyramidal Coordination: A New Blue
Chromophore. Journal of the American Chemical Society, 131(47), pp.17084-17086.
Smith, A., Comstock, M. and Subramanian, M., 2016. Spectral properties of the UV absorbing and near-IR reflecting blue pigment,
YIn1-xMnxO3. Dyes and Pigments, 133, pp.214-221.
Li, J., Lorger, S., Stalick, J., Sleight, A. and Subramanian, M., 2016. From Serendipity to Rational Design: Tuning the Blue Trigonal Bipyramidal Mn3+
Chromophore to Violet and Purple through Application of Chemical Pressure. Inorganic Chemistry, 55(19), pp.9798-9804.
    
|
|
|
j_sum1
Administrator
Posts: 6229
Registered: 4-10-2014
Location: Unmoved
Member Is Offline
Mood: Organised
|
|
Just lovely.
I remember when this pigment was announced. There was a bit of excitement in some quarters over the discovery of a new blue. But I have heard
nothiong for quite some time.
I am really pleased that soeone here has given this a go. It seems like a very successful first effort. And plenty more variations to try.
Thanks for the good write-up and welcome to SM.
|
|
|
draculic acid69
International Hazard
Posts: 1371
Registered: 2-8-2018
Member Is Offline
|
|
Nice experiment and write up
|
|
|
clearly_not_atara
International Hazard
Posts: 2694
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
Incredible! I remember being impressed by the announcement.
Quote: Originally posted by j_sum1  | | There was a bit of excitement in some quarters over the discovery of a new blue. But I have heard nothiong for quite some time.
|
While an interesting discovery, YInMn blue is not economical due to the high price of indium. Cobalt costs about $30/kg while indium is closer to
$200/kg. However, its low infrared reflectivity, high stability and low toxicity recommend it for specialized applications.
However, since the blue color appears to be the result of electronic transitions in the manganese ion specifically, there remains the hope that some
alternatives to indium could reproduce the blue coloration. Yttrium still costs about the same as cobalt, but again the (apparent) safety is relevant.
[Edited on 04-20-1969 by clearly_not_atara]
|
|
|
Texium
Administrator
Posts: 4516
Registered: 11-1-2014
Location: Salt Lake City
Member Is Online
Mood: PhD candidate!
|
|
Welcome to the forum. Fantastic first post!
I remember reading about YInMn Blue a couple years ago and finding it really interesting. I wanted to make it myself, but I don’t have any Y
compounds and didn’t have the time to do it anyway.
Perhaps in line with the less expensive analogs, gallium could replace indium. It’s still not the cheapest metal, but it is far more abundant (GaYMn
blue would also be a very funny name).
|
|
|
j_sum1
Administrator
Posts: 6229
Registered: 4-10-2014
Location: Unmoved
Member Is Offline
Mood: Organised
|
|
My guess is that GaYMn will end up being hot pink.
|
|
|
Boffis
International Hazard
Posts: 1836
Registered: 1-5-2011
Member Is Offline
Mood: No Mood
|
|
Really nice piece of work and welcome to the forum.
I love the colour of the material.
|
|
|
Lion850
National Hazard
Posts: 514
Registered: 7-10-2019
Location: Australia
Member Is Offline
Mood: Great
|
|
Great write up, very interesting. Make me want to go and investigate ceramic ovens 
|
|
|
G-Coupled
Hazard to Others
Posts: 287
Registered: 9-3-2017
Member Is Offline
Mood: Slightly triturated
|
|
Fantastic post - real quality stuff. 
AFAIK, Asbestos is only harmful when it's particulate and airborne, so just handling an Asbestos cloth will provide no danger.
Personally, I would have a look-see at the wiring in that cute vintage kiln and see what's going on - I would think that the electrical construction
would be dead simple, and easy to troubleshoot/repair. It kinda deserves it after what you've put it through, on top of its already long decades of
faithful service. 
[Edited on 30-4-2020 by G-Coupled]
|
|
|
formallydehyde
Harmless
Posts: 5
Registered: 6-4-2020
Member Is Offline
|
|
| Quote: Originally posted by G-Coupled | Fantastic post - real quality stuff.
AFAIK, Asbestos is only harmful when it's particulate and airborne, so just handling an Asbestos cloth will provide no danger.
Personally, I would have a look-see at the wiring in that cute vintage kiln and see what's going on - I would think that the electrical construction
would be dead simple, and easy to troubleshoot/repair. It kinda deserves it after what you've put it through, on top of its already long decades of
faithful service.
[Edited on 30-4-2020 by G-Coupled] |
Thanks for the compliment! As far as the furnace goes, I'd just rather not take the risk of producing a lot of asbestos dust in my apartment, since I
have to live here every day and asbestos fibers will just hang out indefinitely once released. The material looked like it could potentially be pretty
friable. Some of the wiring is probably insulated with asbestos also, the power cord in the back has some frayed cloth looking stuff in the end toward
the furnace. If I had a good place to work on it outside with protective gear that would be another thing.
Also, could we please not make homophobic jokes? Thanks
|
|
|
clearly_not_atara
International Hazard
Posts: 2694
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
In chemistry-relevant news, I don't think gallium would have the right ionic radius. You need a +3 ion but you also need the right crystal lattice.
Indium is 94, Yttrium 104, Ga 76. Your best bet is scandium, 88.5. The others include gold, tantalum and antimony, but the latter will be oxidized to
Sb5+ by Mn3+.
[Edited on 04-20-1969 by clearly_not_atara]
|
|
|
formallydehyde
Harmless
Posts: 5
Registered: 6-4-2020
Member Is Offline
|
|
| Quote: Originally posted by clearly_not_atara | | In chemistry-relevant news, I don't think gallium would have the right ionic radius. You need a +3 ion but you also need the right crystal lattice.
Indium is 94, Yttrium 104, Ga 76. Your best bet is scandium, 88.5. The others include gold, tantalum and antimony, but the latter will be oxidized to
Sb5+ by Mn3+. |
Yeah I just was checking around and apparently this paper claims to have found a metastable YGa1-xMnxO3 purple
pigment:
https://www.researchgate.net/publication/255764926_YGa1-xMnx... But it loses its purple color when heating to ~1000C, and Subramanian's group
showed that the structure actually contains trapped carbonate, a biproduct of the synthesis method used. So the reason it's probably not stable
>1000C is the carbonate gets lost as CO2. Neither group seemed to say what color it was when the carbonate was lost but I'm guessing it
wasn't particularly exciting if it wasn't even commented on or shown.
[Edited on 1-5-2020 by formallydehyde]
|
|
|
j_sum1
Administrator
Posts: 6229
Registered: 4-10-2014
Location: Unmoved
Member Is Offline
Mood: Organised
|
|
Absolutely no intent to offend. My apologies if you took it that way.
My intent was associative rather than phobic: exploiting a sterotype rather than being discriminative. Again, if this came across as anything other
than light humour, I apologise.
|
|
|
fusso
International Hazard
Posts: 1922
Registered: 23-6-2017
Location: 4 ∥ universes ahead of you
Member Is Offline
|
|
y r ppl nowadays so snowflaky and easily offended by such jokes? relax bro
|
|
|
j_sum1
Administrator
Posts: 6229
Registered: 4-10-2014
Location: Unmoved
Member Is Offline
Mood: Organised
|
|
That may well be a modern trend and maybe even applicable in this case. But that discussion does not belong here.
If I have derailed the thread with humour perceived to be inappropriate +hen an apology is warranted.
Back to discussion on pigments.
|
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
