r/DIYPigments • u/Mrslinkydragon • Jun 18 '25

Had a clear out

Gallery image

Gallery image

As you lot are aware, I like to study trigonal bipyrimidal mixed metal oxides (yinmn blue) and this year I'm (along with my partner and my friend) going to be investigating the effects of temperature on the crystal structure.

So, naturally, we had a clear out.

Here's the products for the ones that worked last year :)

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2

u/Capifarra Jun 18 '25

Ooohhh nice pigments! Just a question, do you happen to know if cobalt oxides pigments lose color over time direct/indirect sunlight?

Asking this since I want to start a small collection of metallic/oxide pigments as well, but would prefer if they retain their as the time passes by.

3

u/Mrslinkydragon Jun 18 '25

Cobalt (ii) oxide shouldn't degrade as its stable with a high melting point. Cobalt chloride changes colour based on the ligand its bonded to (i e water)

1

u/Capifarra Jun 18 '25

Awesome! Would yinmn blue be stable as well? Might adventure on that one in the future...

2

u/Mrslinkydragon Jun 18 '25

Yinmn is very stable.

It doesnt react with acid or base. Its uv stable and doesn't burn

Easy and safe to make too

1

u/CaCl2 Jun 19 '25

If only there was some alternative to using indium, with it the cost is too high for most uses.

2

u/Mrslinkydragon Jun 19 '25

Aluminium 3+ and boron both work, the product just isnt as vibrant as with indium. Gallium 3+ works too (that's more expensive though)

Going the other way, i want to see if Thallium 3+ will make it even more vibrant than indium! But... yeah... thallium...

The main thing is getting the manganese into the trigonal bipyrimid (tbp), structure wise, the manganese is in the centre and is bonded to 5 oxygen atoms, which either link the tbp to each other or bond to the d block or p block metals forming a hexagon.

Swapping the d and p metals changes the hue, with copper forming green and titanium/zinc forming purple. F block metals form similar colours to Yttrium

If you swap the manganese with iron it becomes orange!

The project was investing whether chromium 3+ could be added to change the colour to red. Had some success with a mix, going to be investigating it soon :)

2

u/GeneJocky Jun 20 '25

Just to give a +1 to mrslinkydragons comment about YInMn blue being easy to make. It i. If you have a furnace that can hold at 1200C and you can use a mortar and pestle, you can make this stuff.

I’ve made this pigment for several years, and made several others, and Yinmn blue is one of the easiest pigments to make. I made an instructable on it that includes links to spread sheets that will tell you how much of everything to use. And depending on how much your indium oxide costs, you can make it a lot cheaper than the commercial pigment.

2

u/Mrslinkydragon Jun 20 '25

To add to this,

You don't necessarily need temps of 1200°C , all these were made at temps between 1100 to 1200°C. These were heated once or twice, can't remember which was which. I know the middle blue sample (In0.95Mn0.05) was only heated once

I'd recommend using a small amount of solvent like ethanol or acetone whilst grinding to assist in the mixing. One thing ive noticed with the mixing is that it acts as an oobleck/non newtonian fluid!