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The Volatile Chemist
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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?
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I'm sorry. I didn't actually do the lab in my own lab, but in my AP Chemistry course. yes, it was waterglass we used, and I haven't a clue why the
lead silicate isn't formed. Waterglass and silicates in general are rather strange.
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crystal grower
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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.
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JJay
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I did some further research on Mrs. Stewart's bluing, and it appears that it contains Pussian blue, oxalic acid, and ammonia. I am going to attempt to
produce potassium cyanide from it, but I'll discuss that further elsewhere as to not hijack this thread.
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Dmishin
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| 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.
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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.
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Bezaleel
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| 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. |
Take care not to breathe the Te vapors. Search on "telllurium breath" for more info. User and moderator Woelen once named tellurium a "socially
problematic substance" IIRC.
| 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. |
Peculiar, I only got the tabular ones. I'll try again. Did you cool quickly or slowly for the seed 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. |
Looks great!
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]
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crystal grower
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Iodine
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Dmishin
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| 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] |
Opposite of this. Glutamic acid has relatively low solubility (0.8g/100ml). I precipitated it with stoichiometric amount of sulfuric acid (cheapest
acid I have), washed with cold water and then dissolved in HCl. Need to say that precipitate is rather bulky and washing is not easy.
If sulfuric acid is taken in excess, it dissolves glutamic acid again, probably giving its sulfate, which does not crystallize well (very soluble,
forms syrup-like solution).
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Velzee
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| 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 ?? |
Oops! I forgot.
This is where I bought my sodium metabisulfite.
[Edited on 3/14/2016 by Velzee]
[Edited on 3/14/2016 by Velzee]
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"¡Vivá Cristo Rey!"
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crystal grower
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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
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The Volatile Chemist
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Nice. I was just realizing how hard it is to grow nice crystals of most chlorides (non-trans. metal). I had some magnesium chloride and strontium
chloride sitting out to crystallize, and although both formed crystals, it seemed impossible to dry them. So I'd rule out them for growing any good
crystals.
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Cucurbit
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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!
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crystal grower
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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.
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Dr.Bob
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Cucurbit, that is a really beautiful crystal, like having your own pyramid, without have to travel to Egypt. Great job.
My favorite crystal is a chunk from the end of a silicon boule, about 5" in diameter, that looks like a giant Hershey Kiss. I got it from a place
that made silicon wafers and it was supposed to be recylced back in to the melt, but someone there gave it to me as a gift. I have a few 3" wafers
as well, never got any intact 5" ones, they were too valuable.
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Cucurbit
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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!
 
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The Volatile Chemist
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Really nice crystals Cucurbit!
I recently decided to try making some sample crystals of the shape of copper sulfate, to demonstrate its crystal habit (for fun mind you). Although I
initially had some seed problems, I'm growing from a good sized base seed right now. I've always liked crystals but haven't really tried making any
big ones till now. Going to be trying some of these in this thread later, perhaps...
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hyfalcon
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Anyone for NaI(Tl)? I would be curious how one would go about growing one of some size for a scintillation crystal.
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100PercentChemistry
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Tin Ii chloride! When you run a current through it you get tiny crystals of tin.
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crystal grower
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I tried this too and got nice crystals of 2-3cm in lenght. Unfortunatelly, they were very delicate and I wasnt able to get them from a solution.
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Chemist_Cup_Noodles
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| 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!
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Jesus that's a whopping crystal. I bet that photo doesn't do it justice! What do you grow crystals of such size in? I'd like to hear more from you
about your methodology. I know overall it doesn't change much but still, damn son that's nice.
I'll be honest-- We're throwing science at the wall here to see what sticks. No idea what it'll do.
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Cucurbit
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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!
 
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Chemist_Cup_Noodles
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| 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.
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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'll be honest-- We're throwing science at the wall here to see what sticks. No idea what it'll do.
-Cave Johnson, Portal 2
Add yourself to this map of SciMad members! https://zeemaps.com/map?group=388676&add=1
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Cucurbit
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| 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.
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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
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Dmishin
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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.
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Chemist_Cup_Noodles
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| 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. |
Hm, I think I've seen somewhere about using rain repellent. However, once you get it on, could it easily come off? I'm assuming that if it is silicone
and isopropanol, then the isopropanol is probably the main solvent for the silicone and evaporates off. But what if you have a little alcohol in your
solution to get it more saturated? Could it dissolve the silicone?
I'll be honest-- We're throwing science at the wall here to see what sticks. No idea what it'll do.
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crystal grower
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Some pretty K2Cr2O7 crystals.
  
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