How to grow Tin Crystals!

How to grow Tin Crystals!


So this is basically what you need to
carry out this experiment: You need; a stannous chloride solution, a dish to hold it in, some alligator clips, some paper clips and a power source. Each of the paper clips will serve as an electrode, and they’re clamped to either side of the dish using the alligator
clips. The dishes then filled with a few
milliliters of two molar stannous chloride solution (~3 mL 2M SnCl₂) which I made in a
previous video. I’ll provide a link to the stannous chloride video in the
description. Then to the power source, an alligator
clip is attached to the positive and the negative terminals. The moment the
circuit is completed by connecting the second alligator clip, the crystals
should start to grow. The crystals will grow from whichever
alligator clip was attached to the negative terminal. So, after [it] was attached we can see the
crystal starting to grow. It was very interesting for me to see this the first
time but I was honestly quite underwhelmed at how slow it was and how
few crystals were growing. I was very underwhelmed with the results, so I decided that I’m going to need to use something with more current if I
want to get the crystals to grow faster and to get more of them. The crystals are pretty small, flaky and
fragile but if you like you can scoop them up and collect them. So I found an old power supply from a
laptop I used to have. I cut the end off and stripped away about an inch of the wire on the end. The free copper wire that you see
wrapped around the inner white wire is generally the negative or the ground. So it was removed from the white wire and twisted up a little. Then, with the white
wire free a little bit of it was stripped to expose the inner wire, which
is the positive. So now these are going to serve as our positive and negative terminals instead of the battery. And then just like before, we attach an
alligator clip to each of the terminals. In general, the wrapped wire is positive
but depending on the polarity of your adapter it could be negative. In the end, it doesn’t really matter because it doesn’t really matter which side the
crystals grow from. And then, to get things going we plug it in. So now when we use this much more
powerful power supply, we can see that the crystals are growing much faster
than before. However, due to the greatly increased power input it starts to heat up the solution and you can see that the solution on the red side starts to actually boil a little. So what’s happening here is known as a redox reaction. Basically, what happens is that the tin ions are oxidized at one end and reduced at another. So, the stannous chloride starts off as tin
2 plus (Sn²⁺) but at one side receives electrons and another it gives away [electrons]. At the positive side tin 2+ is giving
away 2 electrons to form tin 4+ (Sn⁴⁺) and at the negative side it’s receiving two electrons to form tin
0 or tin metal (Sn). Just for fun, you can reverse the terminals so the tin grows from the other side and you can see that the existing tin
crystals start to shrink. Because the solutions already been used
extensively and it’s pretty hot the demonstration isn’t the most
beautiful thing ever. But, in essence what we’re seeing here is the tin metal is giving up two electrons to form tin 2+ or tin 4+ which can
be re-dissolve in the solution. I opted to redo the experiment with
better lighting and indoors, and the result was much nicer. The crystals grew very nicely and I was quite satisfied with the result. To end the video I’ll
let this play out in real time. [music]

78 thoughts on “How to grow Tin Crystals!

  1. Great video and thank you for warning peeps about getting zapped. I myself have had a close call. Better to use insulating gloves if you can cuz even being careful doesnt change humidity in the air, which can allow electricity to travel through the air more easily.

  2. Safety first,DO NOT use lead tin solder, HCl will burn you, and the gases produced will be poisonous and explosive. If you have a basic knowledge of lab procedures it should be perfectly safe. A few suggestions, it is best to use a constant current power supply. I believe an LM 317 can provide that.(An LM 317 will make a power supply that is variable down to just below 2 volts. A good idea is to simply put a couple of high power (10 Amp) diodes in line with the output. that will drop the minimum output voltage to just about 0 to 20 volts.) And the voltage should be kept down to less than 2 volts. even then you are going to produce some hydrogen and chlorine gas, so you need fresh air. The slower you grow the crystal the closer to cubes they will become. the best i have been able to achieve are about like a pencil stub. With higher currents the crystal will grow out like tin feathers, and i mean they really look like a feather. Another suggestion is to use lead free plumber's solder as your source for tin. Then you can just use a 7 to 10 percent solution of HCL,( muratic acid). the tin will come off of the solder into solution and make the stannous cloride all by itself. Another problem with using pure tin cloride as your starting stock is that you will produce pure tin crystals. Pure tin has the nasty habbit of disintigrating into a grey dust in a few years. I have crystals made from lead free solder that are decades old. And they are still shiny. In conclution DO NOT use lead solder You will probably poison yourself. And yes you can do similar things with copper and silver but they are not as nice, in my oppinion, and i do not know any of the voltage or percentage requirements.

  3. Will this reaction be negatively effected by adding sodium silicate to the solution? My idea is to have the crystals form and be suspended in the sodium silicate which I suspect would present with an increased viscosity because of evaporation of the water it's most often in a solution with because of the electrolysis being carried out upon the solution.

  4. It would be cool to see this in a taller beaker with the negative suspended in the center, and the positive attached to sheets around the perimeter to see if it will grow a spherical shape, or a single sheet at the top to grow a tin tree.

  5. Pro Tip: Unless you need every last inch of cable, don’t cut your power supply cables, right at the plug. You never know when you’ll need that size plug, in a pinch. (Especially, odd ones, like laptop plugs.) Leave a few inches on the plug, for future use.

  6. The solution is not boiling but along with Sn(2+) goes to Sn(4+) you have water oxidation: 2H2O to form 4H(+) + O2 + 4e-. What you see are O2 bubbles evolving on the anode. Contrary to that Sn(2+) + 2e- gives Sn(0) should happen along with HER (hydrogen evolution reaction). Luckily, Sn, Pb, Hg, Cd are bad electrode materials for HER. In fact, they significantly shift the onset potential for HER so that it will happen only at much larger applied potential than what would normally happen on Pt, Au, Ni etc. electrodes. That's the reason why we used to use Hg in Polarography (you can even reduce alkaline metal ions to form amalgams on Hg droplet that serves as an electrode during the Polarographic experiment).
    Cocking is nice but electrochemistry is more fun 😛

  7. It was so beautiful to watch the crystal grow in real time! Please do this again with other metals? Copper would be awesome!

  8. How did you cut your hand? …Also, I have (what I think is) Tin Oxide from dissolving a circuit board in HNO3. Can I rinse the old acid out and put it in HCL to make this Stannous acid? My goal is to return it to its pure metal form.

  9. Well yesterday my recommended video from you was chloroform, at least we’re on to something a little, uhhh, less creepy

  10. It makes perfect sense but I am impressed by how consistent the speed of growth is! Look how the outer edge forms a near perfect circle each time.

  11. For some reason i thought you were metalizing a bubble. Can you blow a bubble with stannous chloride solution? Make a tin bubble?

  12. I used to do it at my high school. I used CuS04 for the solution and carbon that i took from battery for the electrodes. The Cu was grown up from the katode side and we rinse it beneath the sun. It's ended up having solid Cu. I was enjoy that experiment 🙂

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