Liquid for growing crystals

[ScotHill]

Our kids had a few crystal tree sets, where you colour in an absorbent paper tree, add liquid to the bottom which then gets soaked up and creates crystals on the ends of the branches. The crystal liquid is potassium phosphate monobasic, whatever that is, but I understand there are many liquids that you can grow crystals with.

Where can I buy a bottle of liquid potassium phosphate? I've found crystals for diet supplements but I don't know whether dissolving those in water would create the right kind of liquid. If not potassium, what other liquids could I buy without having to buy the whole National Geographic set again for £££s?

And separately, what do we need to buy for growing freestanding crystals, again without buying a whole presentation pack set like the ones below? They're great but pretty much once and done.

[otolith]

Classically, water glass (sodium silicate solution)

https://edu.rsc.org/experiments/making-a-crystal-g...

[Mr Pointy]

Google is awash with information:

https://crystalverse.com/growing-crystals/
https://www.amazon.co.uk/s?k=monoammonium+phosphat...

[ScotHill]

otolith said:

Classically, water glass (sodium silicate solution)

https://edu.rsc.org/experiments/making-a-crystal-g...

Cool thank you. Regarding safety, how corrosive/irritating are those chemicals, is it a problem if a child gets it on their hands, if washed straight off?

[ScotHill]

Mr Pointy said:

Google is awash with information:

https://crystalverse.com/growing-crystals/
https://www.amazon.co.uk/s?k=monoammonium+phosphat...

I know but if you're not sure what you're looking for it's often easier for someone to say 'we bought this from here, and did this, and it worked'.

[Mr Pointy]

ScotHill said:

otolith said:

Classically, water glass (sodium silicate solution)

https://edu.rsc.org/experiments/making-a-crystal-g...

Cool thank you. Regarding safety, how corrosive/irritating are those chemicals, is it a problem if a child gets it on their hands, if washed straight off?

Waterglass is safe - it used to be an egg preservative if I recall correctly. I still wouldn't drink it though.

[otolith]

Not hugely, but I would probably give them vinyl gloves. The larger risk which would concern me is that some of the compounds used to grow crystals are pretty toxic. There was a case I recall where a child died after accidentally drinking a beaker of copper sulphate solution they had left by their bed.

[Simpo Two]

The young Simpo grew sugar crystals by hanging threads into saturated sugar solution. Takes a while but it's simple basic science - and you can eat the crystals afterwards...

[Rich1973]

Copper sulphate produces good crystals.

[Zad]

Table salt (sodium chloride) produces interesting crystal shapes too.

[PlywoodPascal]

You can also do sugar…

Just prepare a saturated solution in hot water and allow to cool slowly.

[Simpo Two]

PlywoodPascal said:

You can also do sugar…

Just prepare a saturated solution in hot water and allow to cool slowly.

Three posts too late

[PlywoodPascal]

otolith said:

Not hugely, but I would probably give them vinyl gloves. The larger risk which would concern me is that some of the compounds used to grow crystals are pretty toxic. There was a case I recall where a child died after accidentally drinking a beaker of copper sulphate solution they had left by their bed.

I remember this really well, because it happened a few years after I had a similar kit as a child. I grew lovely blue copper sulphate crystals. The story freaked me out and I still really throughly check what I'm drinking at night now...

I have since grown many crystals since I am a synthetic chemist working in research. some of my greatest hits:









Most organometallic compounds of Ruthenium or Silicon.

Why crystallise stuff? It's a great method of purification, but also essential for understanding what we've made - we use X-ray crystallography to understand the connectivity between atoms that make up the molecules we've prepared.

Of course nothing will top this - filling an entire flat with a saturated copper sulphate solution and crystallising the compound all over the inside - amazing.

https://ysp.org.uk/art-outdoors/seizure

Edited by PlywoodPascal on Thursday 25th April 11:26

[otolith]

My old A level chemistry teacher's PhD was in organometallic chemistry. He had some worrying war stories along the lines of "the time I had a tetracarbonyl nickel leak and was saved by it spontaneously igniting" and "what phosgene poisoning feels like"

I would hope that safety standards are a bit higher these days!

[budgie smuggler]

Mr Pointy said:

ScotHill said:

Cool thank you. Regarding safety, how corrosive/irritating are those chemicals, is it a problem if a child gets it on their hands, if washed straight off?

Waterglass is safe - it used to be an egg preservative if I recall correctly. I still wouldn't drink it though.

it causes skin/eye burns, I've got a bottle here and it has H314 on the label (Causes severe skin burns and eye damage)

Edited by budgie smuggler on Thursday 25th April 11:55

[eharding]

PlywoodPascal said:

You can also do sugar…

Just prepare a saturated solution in hot water and allow to cool slowly.

Prepare a little extra, and when cool mix the surplus sugar solution 1:1 with rum, pour over crushed mint leaves and lime segments mixed with ice, stir well, add more ice and top up with soda water. Makes the science so much more enjoyable.