Crystal Growing

Got the following crystals overnight.
This is in the bottom of a 1L beaker.
Will post more when I get them out of the beaker.

Edit by Chemoleo:
Beautiful crystals but please state what the substance is!

[Edited on 14-7-2008 by chemoleo]

Thanks
I used Copper Carbonate and distilled white vinegar.
The copper carbonate was made from copper sulfate and sodium bicarbonate.
The copper sulfate was made by electrolysis of Magnesium Sulfate with a copper anode.
(Yup, from copper metal to copper acetate in 3 painstaking slow steps )

The crystals seem more green to me, but I've noticed that people draw the line between blue and green at different colors. But it's certainly bluer than a 532nm laser.

Quote:

Originally posted by indigofuzzy Quote: Vera nice. What were your starting materials? What color are they? I.e., more blue than green, more green than blue, or blue-green, etc. (I'm thinking the camera may distort this color somewhat.) Thanks I used Copper Carbonate and distilled white vinegar. The copper carbonate was made from copper sulfate and sodium bicarbonate. The copper sulfate was made by electrolysis of Magnesium Sulfate with a copper anode. (Yup, from copper metal to copper acetate in 3 painstaking slow steps ) The crystals seem more green to me, but I've noticed that people draw the line between blue and green at different colors. But it's certainly bluer than a 532nm laser.

A beautiful crystal aglomerate:

Now this is something I'd like to be able to grow (anyone, how?):
Stibnite

Stibnite, sometimes called antimonite, is a sulfide mineral with the formula Sb2S3

http://en.wikipedia.org/wiki/Stibnite

Photo taken at the Museum of Natural History, London

Size: 30 cm wide, 25 high and 25 deep.

[Edited on 14-10-2008 by chemoleo]

Crystal Healing

Makes sense to me

Nonetheless a good source for interesting minerals.
http://www.crystalage.com/ (where the excerpt from above is from).

[Edited on 13-10-2008 by chemoleo]

Quote:

Originally posted by chemoleo And this is how they help you to battle disease, of mind and body: Quote: Chemical Composition The vibrational frequency of the elements that make up crystals is also used in crystal healing. To understand the importance of the chemical make-up of minerals, let's look at a few examples: * Calcite ( CaCO2), you will find by looking at the periodic table, is a calcium carbonate. Most people will know that calcium is the main constituent of the skeletal system, and therefore calcite is often used in crystal healing to help mend fractures of bones. * Hematite (Fe2O3) is an iron oxide. Iron helps to maintain healthy red corpuscles and oxygenate the blood, and hematite is frequently used to treat anaemia as well as circulatory problems. * Malachite (Cu2(CO3)(OH)2) contains mainly copper, which draws off heat, and can therefore be used to reduce inflammation. This is the idea behind the use of copper wrist bands to treat osteoarthritis. Makes sense to me [Edited on 13-10-2008 by chemoleo]

My supplies of ferrous salts were covered with ferric salts so I decided to recrystalize them to try to get better quality.

For the ferrous ammonium sulfate hexahydrate I dissolved up the crappy crystals I had made previously, added a bright nail and kept the soln near boiling for a few minutes. The solution cleared to a yellow-green translucence. Then I filtered hot into a crystalizing dish. In three days large pale-green crystals had formed (see below on right). These were air dried. As you can see some ferric salt has formed on the edges of the cystals.

For the ferrous sulfate heptahydrate I started with crappy pottery grade material. I dissolved some in water, added a bright nail and a couple ml of H2SO4, heated and filtered. When the crystals were about 5mm I washed them twice w/water, then twice with alcohol (S-L-X). These were air dried. The crystals in the 2 leftmost bottles appear to be somewhat efflouresced. The right bottle crystals were harvested when about 2mm in diameter and dried at room temperature, but not over dried. They appear to be of the best quality.

Whereas the ferrous ammonium sulfate is known for its supposed resistance to oxidation, my experience has been that the ferrous sulfate is more reisistant. However, with the FAS I did not wash the crystals with water and alcohol.

What has beenyour experience making these salts?

Reference: "A Course in Inorganic Preparations," by Henderson & Fernelius

Well come on DJF90, tell us how you did it!

[Edited on 7-3-2009 by Magpie]

Quote: Originally posted by chemoleo

Same here - I was hugely disappointed with ferrous ammonium sulfate - not only is the colour ugly, but also it's prone to oxidation. But I didn't have much good experience with FeSO4 hydrate either... the iron curse!

Then, I just grew commercial FeSO4 and AS (reagent grade).
I gave up on these trials - one has to grow them under anaerobic conditions to get large crystals without brown oxides, and cover them with laquer or something as soon as they face the air.
Oh, and the same with FeSO4 on its own - very pretty while they last but unfortunately not for long!

[Edited on 22-1-2010 by chemoleo]

Quote: Originally posted by Paddywhacker

There are many chemicals that are only very slightly soluble in water that might grow crystals vie the hydrothermal method. I have been thinking that Thiel tubes might be useful in this context. Has anybody experimented with ambient-temperature hydrothermal methods? What apparatus was used?

Was cleaning out a 2l bottle which had been used to make lead acetate through the CuO/AcOH/Pb process (had a hard lead acetate/copper powder/lead filing mass at the bottom) and as the hot, filtered wash waters cooled I got this:

http://md1.kapsi.fi/kuvae/lead_acetate1.jpg
http://md1.kapsi.fi/kuvae/lead_acetate2.jpg

The crystal is around 9cm long.

A bit of a double post, but, behold:







Ignore the Ru3(CO)12, just a colourful sample I had sitting around. All the others are grown crystals. I had trouble forming a good CoCl2 crystal because the hydrate was forming first, and eventually the blue CoCl4 2- began crystallizing out (excess Cl- from CoCO3 + HCl) - the vial is only a small sample, I have a much larger chunk in another jar.

I may try heating the entire mass to dehydration to obtain powdered CoCl2, followed by recrystallizing it slowly from just distilled water. The crystals are intensely dark, not even a 1000W tungsten light shines through these crystals.

Quote: Originally posted by aonomus

It sounds strange, but I was able to grow a CuSO4*5H2O crystal by placing a beaker of concentrated solution into a dessicatior loaded with NaOH. All my other attempts at room temperature evaporation haven't gone all too well with NaCl (tends to effloresce) or MgSO4 (forms needle like crystals far too readily even with insulation to keep temperature high and cool slowly). Perhaps alum crystals are easier to grow?

Holden and Singer — Crystals and Crystal Growing

Prismatic Copper Sulfate

Observed something interesting this evening.

Solution: an unknown mixture of CuSO4, NaCl and etc. In particular, I think the chloride concentration is low enough that CuCl4<SUP>2-</SUP> is not forming in large concentration. The solution is bluish green, not bright green. Hence, the copper is crystallizing as CuSO4, while a little NaCl (if that's what it is) crystallizes as colorless crystals. The remainder will probably eventually produce the neon-green Na2CuCl4, possibly as an intederminate mixture with NaCl and CuSO4.

Method: solution was placed in a drying tray and placed over a warm spot. A gas stove was used, with pilot lights below the working surface which heat it in spots to about 90C. This caused two convienient hot spots on the tray, where little to no CuSO4 formed, but NaCl formed easily. This suggests little change in solubility for the NaCl, which is consistent with its known properties.

Photos: these show the crystals, which seem to be prismatic, and monoclinic I think. A dramatic change from the sharp, hard rhombic habit of pure CuSO4. These crystals were rather weak and easy to crush, though they adhered to the tray quite well.

The tray is yellow plastic, so most of the background also looks yellow. The yellowness is enhanced by the residual supernatant, which was viscous and drained poorly. White streaks glint from its surface, while around the blue crystals, a green halo emphasizes the color of the solution.

Tim

I too have noticed the different habits of copper sulfate- It actually switches between a few- Your normal prismatic, then the crystals grow flat, then a much more cubic prismatic (I can provide pics, if you'd like) which is a lighter shade of blue, then monoclinic.

Also of note- I've discovered that the monoclinic crystals can be melted and used as inlay I have no testament to the longevity of this procedeure, though!

What you need to do is keep adding sugar into boiling water (or at near bioling) untill NONE will dissolve, then put the beaker/jar into a great thermal ballast, allowing it to cool VERY slowly over a few days. That'll do the trick- I got about 1cm talkl sugar house-shaped crystals

Just in case someone wonders what a room looks like that has been filled with a hot solution of CuSO4 after cooling:
http://www.guardian.co.uk/artanddesign/2008/sep/04/art



I think I may try a project like that one day!

But obtaining 80,000 L of sat. CuSO4 could be tricky!

Quote: Originally posted by Paddywhacker

There are some cheaper-than-normal Thiele tubes on eBay just now.

I was wondering who bought all of those.

I hear they have a high resale value as esoteric walking canes among the gentlemanly garden gnome community.

[Edited on 24-1-2011 by peach]

Crystal Growing

With the mixed crystal idea, recrystalisation is used specifically to purify one salt from the other, as the salts tend to want to solidify on a lattice that is of their own kind.*

This page is written by someone else trying exactly the same Alum experiment and ending up with opaque solutions

You may be right with regards to the seed crystal hitting the bottom in the others, and other crystallisation points appearing.

With a week to go, time is of the essence!

I would offer the possibility of an entirely different approach. The salts you are using, like copper sulphate, loose their pretty colours when in their anhydrous form (when all of the water of crystallisation is driven off).

You can achieve this by simply roasting the more stable salts, like copper sulphate, in the open air. The water content goes through specific stages at different temperatures, as discussed in the "chemical properties" section of the Wiki article.

As soon as any water gets near the powder, it will go back to the beautiful blue.

This is a very visual demonstration and one that can be done quickly if she'd like to do it in front of the teacher or class.

There is also a wide selection of the level of detail you can go into as to what is happening. The water is changing the colour by forming ligand coordination complexes with the salt, which affect the orbits of the electrons and how they adsorb light; the colour they show is the colour they are not adsorbing.

After googling what 9th grade is in the US (as I'm from the UK), I think it would suffice to say, it's making the salt molecules group together and share electrons in a different way. Paint pigments are based on transition metal complexes as well.

If you scroll down this Wiki article to "Pigments by chemical composition", you can see there are many of them based on copper; Azurite, Han purple, Egyptian blue, Malachite, Paris green, Phthalocyanine Blue BN, Phthalocyanine Green G, verdigris & viridian. But they don't rely on water of crystallisation to maintain their colour - a noteworthy difference. Synthetic pigments where high tech stuff in ancient Egypt and Rome, and brightly coloured paintings, objects and clothes where a sign of being rich.

Today's equivalent are quantum dots, which absorb one band of light and emit a very specific, narrow band of another - costing hundred to thousands of dollars per bottle.

Another point that ties in with this is plants, as the petals use metal ion complexes to produce the bright colours needed to attract bees - the brightness is affected by soil pH (with bright flowers usually wanting more acidic pH's). And the chlorophyll that sustains life on Earth contains a Magnesium complex.

There are also different things she can say about the two different forms of hydration in her experiment. Anhydrous salts, due to them not being crystalline, can be easily ground to extremely fine powders, whereas those with water of crystallisation tend to be big lumps (if you can buy a decent sized crystal from eBay, she could use that as an example of what the anhydrous salt won't easily do).

She can also use the property to demonstrate a use. If the salt is added to a none polar, dry solvent, nothing will happen. If there is moisture in the solvent, the powder will begin going back to it's more well known colour. So it can be used to detect the presence of water. She could use colour changing silica gel, used to dry flowers, as an example of where that's useful in everyday life and how it's used (by baking it in the oven to drive the moisture off again).

She can liken the process to a container of table salt 'going funny' if left in a damp cupboard (particularly if you have one in your cupboard). As well as how lumps form in powders and how this can clog up machinery that processes them.

The only safety problems are a.) don't eat it (which applies for growing crystals) b.) when you grind up anhydrous salts, they will tend to float around in the air, even if you're doing it gently in a mortar and pestle.

The salt WILL end up up your nose and with something like copper sulphate, it WILL sting. You'll be able to taste copper coins in your mouth almost instantly, which is nice at first, but starts to get annoying and burns because it lingers for hours inside your nose. A dust mask is a good idea.

Transition metal salts will work better for the demonstration because you'll get bright colours. For obvious reasons, you want to avoid the more toxic options; like the chromates. Some salts, like ferric chloride, will also decompose if heated in the open atmosphere, releasing hydrogen chloride. Copper sulphate is a safe bet, and they likely use it in her classes anyway.

The salt will heat up as it's rehydrated. Which provides another example of how the process is reversing; heat is needed to drive the water off, and then heat is given back out as the water is put back.

This may seem somewhat boring, but then, crystal growing is the de facto standard for a lot of science projects it seems. With this example, whilst you don't get big crystals (which no one has seen you grow anyway, so they could be off eBay), you see it happening immediately, it advances on the growing by demonstrating the different properties and seems more unique to me.

I would imagine a chemistry teacher would be more impressed by linking all the properties and uses together, as opposed to seeing another crystal.

To show off, she could say how testing for water is extremely important in some chemistry experiments. In university labs, they will use something like the Karl Fischer method; which doesn't work in the same way, but it's testing for the same thing.

If you put a sample of the freshly baked salt on a cheap pocket scale at the beginning of the demonstration, you will likely be able to see that it has gotten heavier by the end, despite not being pure blue again, as it picks moisture up from the atmosphere.

"This is one of the reasons why chemicals must have their lids put back on straight away" <---- every chemistry teacher is going to like hearing this.

Then call up Aldrich and ask them to send you an empty Sure Seal bottom by express delivery for urgent science project work.

Worth a try! The worst they'll say is no.

NurdRage has an Alrich account, and he's lurking around on here. Maybe you can harass him into scoring you an empty bottle.

Here's a page all about the process

If you follow this example, using a test tube for the drying, you can show the water leaving. I've dried quite a few salts by emptying them out onto the hotplate and roasting them that way, but the water will come off as steam, which isn't as graphic as droplets. It can also get messy (as it splatters) and kids could burn themselves doing it.

Water on anhydrous copper sulphate - need to be careful you don't get any fine powder up your nose as the water goes on


A 3,000 year old blue pigment found in Egypt


Chlorophyll A


[Edited on 4-2-2011 by peach]

Erm... yeah... there is a price on that information.

I want to see the project.

Deleted text because of replied post removed...

Robert


[Edited on 3-3-2011 by Arthur Dent]

Quote: Originally posted by hissingnoise

I once read an article somewhere where German researchers grew very large crystals of HMTD. They found that, at a certain particular size, the crystals detonated entirely spontaneously, due presumably, to lattice-strain!

Quote: Originally posted by Sedit

Quote: Originally posted by chemoleo   Same here - I was hugely disappointed with ferrous ammonium sulfate - not only is the colour ugly, but also it's prone to oxidation. But I didn't have much good experience with FeSO4 hydrate either... the iron curse! I know this is a rather old post but how did you attept to make the FeSO4 crystals chemoleo? I boil iron(steel?) in H2SO4 before which left me with a grey material IIRC which turned green with the addition of H2O. The green solution was filtered and left overnight in a jar where Large FeSO4 crystals grew all over the bottom with some rather large almost 1 ince in size. If left out oxidation is a huge problem and the "crystals" turn earth tone red. The solution also began to form brown precipitate until the Green color was completely gone. I think the trick is to start with as concentrated solution as possible and cap it ASAP and allow it to grow or else it will just form brown shit.

Quote: Originally posted by GreenD

you guys ever see this cave in russia? http://www.stormchaser.ca/caves/naica/Naica_08.jpg

Quote: Originally posted by GreenD

you guys ever see this cave in russia? http://www.stormchaser.ca/caves/naica/Naica_08.jpg

Some almost finished stannous chloride crystals.

Crystallization chamber

Quote: Originally posted by aonomus

Thats interesting that 5-10% NaOH causes the NaCl to saturate. I'll have to try that this week. I'm also in the process of building a crystallization chamber based on the rotating platform setup the LNL used to grow massive KDP crystals for their big lasers. http://education.llnl.gov/crystals/Sketch.html [Edited on 25-7-2010 by aonomus]

Quote: Originally posted by Sniffity

I also tend to use the seed crystal on a string method for growing large crystals. I get annoyed to no end by the string being unremovable after this D: I've tried planting a single seed crystal on the floor of the beaker, but invariably more crystals will form (I'm guessing due to seeding by impurities) which will eventually trap my big crystal on the bottom. Any ideas on getting a large crystal without the use of a string?

Quote: Originally posted by knowledgevschaos

A few people seem to have trouble with a crust of crystals creeping up the edges of the container. I've had this problem too, particularly with copper sulfate. My theory is that this happens because the meniscus on the glass draws the solution up into a thin layer that evaporates more rapidly.

Quote: Originally posted by knowledgevschaos

I think that by rubbing the glass with an oil / petroleum jelly, the container would repel water, and this wouldn't be a problem. I haven't been able to test this yet though.

Quote: Originally posted by knowledgevschaos

Solutions going moldy also seems to be a problem for many compounds, especially sugar and rochelle salt

Quote: Originally posted by knowledgevschaos

.. and I think it could happen to ammonium dihydrogen phosphate too.

Quote: Originally posted by knowledgevschaos

I've even had magnesium sulfate grow microbes (how an organism can thrive in a saturated MgSO4 solution is beyond me!).

Quote: Originally posted by mayko

tied for first: these crudlings, surviving in the face of impressive osmotic stress and feeding on ... ?

Quote: Originally posted by Metacelsus

Life, uh, finds a way.

Nickel Sulfate Crystal

This one took about a month and a half.




It's actually much more green than the camera shows.

Quote: Originally posted by knowledgevschaos

A few people seem to have trouble with a crust of crystals creeping up the edges of the container. I've had this problem too, particularly with copper sulfate. My theory is that this happens because the meniscus on the glass draws the solution up into a thin layer that evaporates more rapidly. I think that by rubbing the glass with an oil / petroleum jelly, the container would repel water, and this wouldn't be a problem. I haven't been able to test this yet though.