Chemicals for crystal growing

Quote: Originally posted by Bezaleel

@Volatile Chemist: I keep wondering about your procedure for crystal growing in silicic acid gel. You say that you combine silicic acid with dilute acetic acid, but silicic acid is a hard substance. Thus it seems like you combined sodium silicate solution (waterglass) with acetic acid and lead acetate solution. But if that is so, then why is there no lead silicate being formed? Or is there, and is metathesis with KI what happens next?

Quote: Originally posted by Bezaleel

That's peculiar as you get a lovely hexagonal bipyramid. Wish I had obtained a seed crystal like that! Did this just form in your solution? I only got tabular crystals from K2SO4.

Yes, I took small seed crystal of such form, and it just grew bigger. I also get tabular and stick crystals sometimes, but bipyramidal are more usual.

Actually, that's an interesting question, how K2SO4 can form a crystal with hexagonal symmetry. Wikipedia says that it has orthorombic crystal system, so order-6 symmetry should not be present. However, I remember reading somewhere that this compound is prone to forming cyclic twins, so probably, my bi-pyramid is not a single crystal, but 3 twinned crystals.

By the way, here is another compound that crystallizes really well: glutamic acid hydrochloride. I measured solubility to be around 50g/100ml. Finally, I have found some application for the sodium glutamate from the Chinese species shop.

Quote: Originally posted by crystal grower

Have anyone tried growing crystals of tellurium? If yes could you post the procedure (I assume they are being grown from melt) and eventually some pics please? Thanks.

Quote: Originally posted by Dmishin

Quote: Originally posted by Bezaleel   That's peculiar as you get a lovely hexagonal bipyramid. Wish I had obtained a seed crystal like that! Did this just form in your solution? I only got tabular crystals from K2SO4. Yes, I took small seed crystal of such form, and it just grew bigger. I also get tabular and stick crystals sometimes, but bipyramidal are more usual. Actually, that's an interesting question, how K2SO4 can form a crystal with hexagonal symmetry. Wikipedia says that it has orthorombic crystal system, so order-6 symmetry should not be present. However, I remember reading somewhere that this compound is prone to forming cyclic twins, so probably, my bi-pyramid is not a single crystal, but 3 twinned crystals.

Quote: Originally posted by Dmishin

By the way, here is another compound that crystallizes really well: glutamic acid hydrochloride. I measured solubility to be around 50g/100ml. Finally, I have found some application for the sodium glutamate from the Chinese species shop.

Iodine

Quote: Originally posted by Bezaleel

How did you separate the sodium chloride from your sodium glutamate? Does it just crystallise out first, leaving the glutamic acid in solution if the pH is low enough? [Edited on 11-3-2016 by Bezaleel]

Quote: Originally posted by crystal grower

Quote: Originally posted by Velzee   Chevreul's salt, anyone? xD By the way; those are some beautiful photos! [Edited on 1/10/2016 by Velzee] [Edited on 1/10/2016 by Velzee] Chevreul's salt is almost top secret u cant even find it on wikipedia. I'd like to growCu3(SO3)2 crystals too but i dont have sodium metabisulfite to prepare chevrls salt. Do you know where could I buy it ??

This is my article about growing pottasium dichromate crystals.
It is easy to do and crystal u will get are really nice .

http://chem.pieceofscience.com/?p=937

Great topic, good reason to get out of lurk mode for once - first post!

Here's a good old potassium aluminium alum crystal, the longest side is now 48 mm. Slow evaporation method, this one took > 6 months.
The photo doesn't do it justice!

Wow, that's gorgeous, it looks like huge diamond .
Did you do something to prevent it from dehydration?
If not, do it right now! It would really pity to lose this one.

Thanks guys!

Yes, I should put it in a jar when ready to protect it from dehydration, but it will be in its growing bath until it's... hmm, 6 cm mayby. A few days ago and I dropped it - can you believe it ... The tip broke off and has to regrow!
But chrome alum is probably more vulnerable to dehydration, the crystal at the right had almost completely degraded to a light purple powder, but I managad to re-grow the remaining core into its original shape. Remarkable how it seems to have a memory!

Also, a picture from some NaCl crystals I'm growing from sea salt. It's a difficult compound to grow into nice crystals but it's possible. I suspect the clumping agent (often ferrocyanide) in ordinary table salt prevents proper growth, it's like a negative catalyst. I hope I can grow these to a few cm, they are like architectural models!

Quote: Originally posted by 100PercentChemistry

Tin Ii chloride! When you run a current through it you get tiny crystals of tin.

Quote: Originally posted by Cucurbit

Great topic, good reason to get out of lurk mode for once - first post! Here's a good old potassium aluminium alum crystal, the longest side is now 48 mm. Slow evaporation method, this one took > 6 months. The photo doesn't do it justice!

Tnx! I'm using a tray from soft plastic, intended for heating microwave meals. Hydrophobic plastic is better than glass because there is less chance of crusts creaping up at the walls. I'll soon have to buy a bigger one

Weekly maintenance consists of filtering the solution and replenishing what was lost due to evaporation. I cover the tray with a 'roof' of paper to protect it from dust and slow down evaporation. It's standing in a small unheated unused room with a rather constant temperature. The rest is just 'neglect tek'

I'm glad to see the big one's tip has already grown back in a week!

Quote: Originally posted by Cucurbit

Tnx! I'm using a tray from soft plastic, intended for heating microwave meals. Hydrophobic plastic is better than glass because there is less chance of crusts creaping up at the walls.

Quote: Originally posted by Chemist_Cup_Noodles

Quote: Originally posted by Cucurbit   Tnx! I'm using a tray from soft plastic, intended for heating microwave meals. Hydrophobic plastic is better than glass because there is less chance of crusts creaping up at the walls. Wow, that's a pretty good idea. Never ever would have thought of using a plastic tray to fix that issue, which has actually been quite a pain in the ass for me recently.

I have to admit it wasn't my idea, I just read it somewhere, applied it and it seems to work!

And it's logical: the more water-repellant the container is, the better.
Glass attracts water, the meniscus is hollow, the solution tends to creep up by capillary suction and evaporation at the crusts's high surface area... a positive feedback loop.

It's no guarantee, without a paper cover I still got crusts, but I hope it helps

Quote: Originally posted by Dmishin

I've found another easy method to avoid crust growth: apply automobile rain repellent to the glassware. I bought a bottle in a nearest automobile accessories shop, and it works really well (btw it works on glass much better than on plastic). According to the label, the rain repellent is made of silicone and isopropanol.

Some pretty K2Cr2O7 crystals.

Quote: Originally posted by Chemist_Cup_Noodles

Oh my god do I love the look of chromates and dichromates. For the life of me I can't find a good source of the anion, or even of chromium itself in order to make some. Maybe I'll just have to buy some and recrystallize it. I do wish that chromates were more soluble though. Anyone know good solvents for them? The mineral crocoite (lead chromate) is beautiful but insoluble in water. But crystalgrower, if those are your crystals I'd love to hear the details on how you made and grew them. Chromium is seriously one of my favorite transition metals.

Frankly, these crystals have come from solution which I have forgotten somewhere in mess in my lab and when I found it after few months, there was a pretty surprise waiting for me . So time is best recipe IMO.
But if you want to try to grow these crystals a lot faster, you can try this procedure: http://chem.pieceofscience.com/?p=937. And Im sure you can get better results than mine. Although k2cr2o7 has only little water solubilty at room temperatures, the solubilty rises drastically with bigger temperatures, so repeated cooling seems to be very effective for crystal growing.

Quote: Originally posted by crystal grower

Frankly, these crystals have come from solution which I have forgotten somewhere in mess in my lab and when I found it after few months, there was a pretty surprise waiting for me . So time is best recipe IMO. But if you want to try to grow these crystals a lot faster, you can try this procedure: http://chem.pieceofscience.com/?p=937. And Im sure you can get better results than mine. Although k2cr2o7 has only little water solubilty at room temperatures, the solubilty rises drastically with bigger temperatures, so repeated cooling seems to be very effective for crystal growing.

Thanks .
Our sources are various, we buy something o f course, other stuff we synthese ourselves, and also a lot of experiments has hegi done at university lab.
Sometimes we must improvise a little, but we are trying our best to be as profesional as possible. We also accept any donations, though finding a sponsor is very hard of course.
A lot of that great synthesis is Hegi's work so don't think that Im some super chem-kid lol.
You're partially right with the alums, you can find a good explanation on wikipwedia: https://en.m.wikipedia.org/wiki/Alum
And to tell something about the "spring problems" you mentioned, just look properly at the third photo of the p. dichromate crystals that i have taken (that small fly in it ).

Nice bichromate crystals!

And poor insect - unless it's a mosquito, I hate those

Which reminds me of something... many years ago I used potassium bichromate for gum prints, and got a nice crystal after evaporation of leftovers. I'll see if I can find it and take a picture tomorrow.

And Cup_noodles, I can't wait to see some pics of your alum crystals!

Ammonium Chloride surprisingly makes needle-like crystals, something at least I hadn't seen before.

@the volatile chemist
Once i grew nh4cl crystals with needle like shape too, and they had hashtag reminding layout ### .

Quote: Originally posted by crystal grower

@the volatile chemist Once i grew NH4Cl crystals with needle like shape too, and they had hashtag reminding layout ### .

Yeah, they were kinda unique, It might've had to do with excess ammonia or HCl, to be honest I forget which I used. What other shape grew for you besides needle-like? I just got a crust with beads, and then the needle-shaped ones.

these are crystals of nh4cl that I´ve grown few years ago (I didnt care much about the procedure in that time, I just dissolved some sal ammoniac in the water and waited what it will do ).
It´s interesting that it crystallized into "three forms". At the very buttom a crust was formed, above a # like needles crzstallized and at the top were something like prisms and another crystastals crzstallized on them (reminding me sceptre quartz)
Sal ammoniac is really interesting stuff and I´ll maybe write an article about it in near future .



[Edited on 1-5-2016 by crystal grower]

Very nice ammonium chloride crystals!

Here's this potassium bichromate crystal. Old, impure and damaged... in my memory it was much nicer but hey, I promised to post a picture!

Potassium ferrioxalate crystals, contaminated with potassium oxalate and chloride:

Praseodymium sulphate octahydrate

On pg 3 of this thread, Nezza posted a beam-shaped crystal of Pr2(SO4)3.8H2O.
Mine appear to have a somewhat different form. Here are 4 pictures of the same crystal. I needed to stop growing it further, because I ran out of solution.
The long side is less than 1 cm long.



[Edited on 9-2-2017 by Bezaleel]

Quote: Originally posted by Bezaleel

On pg 3 of this thread, Nezza posted a beam-shaped crystal of Pr2(SO4)3.8H2O. Mine appear to have a somewhat different form. Here are 4 pictures of the same crystal. I needed to stop growing it further, because I ran out of solution. The long side is less than 1 cm long. [Edited on 9-2-2017 by Bezaleel]