Silver hexachloroosmate from scratch

Added: 2026-06-04

[00:00:00]Okay, this is my second attempt at making silver hexachloroosmate from scratch.

[00:00:07]Once again, I am starting with a solution of bleach that I've added a somewhat considerable amount of sodium hydroxide to, so it is very, very, very caustic, which is good for preventing osmium tetroxide vaporization.

[00:00:25]Now, I don't think the camera can pick this up, but there's a very small amount of either sodium perosmate or sodium osmate on the bullion still, on the osmium bullion.

[00:00:36]So, when I put it in, some of that might dissolve, but the metal will not.

[00:00:41]The metal will not dissolve in bleach at room temperature. It needs to be heated to higher temperatures.

[00:00:47]It's a very inert metal. It will not dissolve in hot aqua regia. It will not dissolve in hot acid peroxide.

[00:00:55]Um, it will not dissolve in hot concentrated sulfuric acid.

[00:01:03]And even concentrated nitric acid won't react with it at room temperature.

[00:01:08]Put it in there now.

[00:01:11]As you can see, like I said, it is not dissolving at room temperature.

[00:01:16]The metal requires very high oxidation potential before it will actually react.

[00:01:21]That's why we're going to put it in boiling bleach.

[00:01:25]All right, we're getting up to temperature.

[00:01:28]The metal is dissolving.

[00:01:30]We're producing a solution of sodium perosmate.

[00:01:34]I'm going to need to dissolve quite a bit more this time if I'm going to successfully make this make the silver hexachloroosmate salt.

[00:01:50]Okay.

[00:01:56]All right.

[00:02:00]Put the cap back on.

[00:02:03]>> [clears throat] >> A little bit more.

[00:02:15]All right.

[00:02:16]Probably a little bit more.

[00:02:22]Just to be sure.

[00:02:26]All right, there we go. That's good.

[00:02:28]That's probably good.

[00:02:31]Okay, so now we have a very dark red solution of sodium perosmate.

[00:02:38]Now I need to add hydrogen peroxide to this to neutralize any remaining bleach so I can start reducing it.

[00:02:45]Okay, you'll see here this is a very very dark red.

[00:02:52]All right, let's transfer it over.

[00:02:55]Remove solid contaminants as possible.

[00:03:13]Okay.

[00:03:18]Okay, now I'm just going to add some hydrogen peroxide to the solution to neutralize the bleach.

[00:03:41]Oops.

[00:04:09]>> Okay.

[00:04:10]Now, I'm going to put the cap on this swirl it around cuz it's getting a little And this is the There we go.

[00:04:23]Still a nice deep red color. That's what I like to see. That means we got a lot of osmium in there.

[00:04:48]All right.

[00:04:49]Hopefully, we neutralize a lot of that.

[00:04:59]All right, we're getting uh turned to red orange now.

[00:05:04]And I'm going to start adding isopropyl alcohol to this to reduce it from sodium perosmate to sodium osmate.

[00:05:17]And look, it's going already.

[00:05:22]It's already reducing. Look at that.

[00:05:26]Add some more, I think.

[00:05:30]Add a bit more.

[00:05:37]What? There we go. Look at that color change.

[00:05:41]It's pretty damn amazing.

[00:05:48]Rather quickly, too.

[00:05:50]No heating required.

[00:05:53]All right, this next part involves a lot of stirring and a lot of heat.

[00:06:00]Just turn it up a bit. Here we go.

[00:06:03]Stirring back on.

[00:06:13]And let's crank up the heat.

[00:06:17]Let's get this to reduce even further.

[00:06:31]So, what we're doing now is going to we're going to start heating up the isopropyl alcohol, so that way it can reduce the sodium osmate to osmium dioxide.

[00:06:43]This will also boil off the isopropyl alcohol, and while we're at it, we can also boil off some water to make this solution more concentrated again.

[00:07:06]Still waiting.

[00:07:10]Oh, wait. Now, it's starting to darken.

[00:07:13]Starting to darken right now.

[00:07:16]All right, that's cool.

[00:07:19]That's good.

[00:07:20]That's very good.

[00:07:28]All right, I don't want that bubbling too much, but yes, we do want to start reducing the osmium in there.

[00:07:43]And I also definitely want to boil down that solution a bit as well.

[00:07:52]I'm going to let this run for a bit.

[00:08:13]Okay, so I've been boiling this down for a while.

[00:08:17]Um So now, I'm going to take it off and I'm start adding isopropyl alcohol to it.

[00:08:31]Okay, here we go.

[00:08:41]And add a little more just for good measure. Here we go.

[00:08:49]Put the cap on, swirl it around a bunch, get it nice and mixed up.

[00:08:54]Get it really mixed up.

[00:09:03]And okay.

[00:09:05]Back to the heat.

[00:09:07]All righty, we are back on the heat now.

[00:09:10]Loosening this cap up a bit more. There we go.

[00:09:24]All right, so what I'm doing now is I'm just adding even more isopropyl alcohol to this.

[00:09:31]All right, because you want to just keep on doing this until you get all of the osmium dioxide out of there because you take a look at that.

[00:09:42]Actually, you can't see, but it's still purple in there. So, that's how I know I haven't got all of it out yet or even all that much of the total.

[00:09:57]But, I know if I centrifuge this now, I get all of it separated, the solution is going to be still quite purple.

[00:10:09]And so, here we are back on the heat again.

[00:10:13]I have to do this over and over and over and over and over again until all of the dioxide is out of solution.

[00:10:21]It's going to take a while and probably going to go through a lot of rubbing alcohol, but you know what? It's worth it because you won't get any colloids this way.

[00:10:30]So, taking it off the heat again, and already you can see at the top the osmium dioxide is beginning to settle at the bottom.

[00:10:39]Um and the isopropyl alcohol is thanks is to thank for that because it promotes coalescing.

[00:10:49]Absolutely.

[00:10:54]But, I am guessing I still have a long way to go to get all the osmium dioxide out of there.

[00:11:01]Okay, now I'm just centrifuging it to uh get some of the osmium dioxide separated from the solution.

[00:11:06]And uh this is very, very coated with uh some of the dioxide. It's not much, though, but it's not nice to look at. I can't see how purple the solution is. So, yeah.

[00:11:21]All right, so as you can see, the solution is still quite purple even though I have isolated quite a bunch of the dioxide, but there's still quite a ways to go.

[00:11:34]All right, so I put this on pause so I can go inside, have some dinner, and just relax.

[00:11:39]Now I'm getting back to it.

[00:11:42]This takes a long time and it'll probably go into tomorrow as well.

[00:11:47]Yeah, this is very time-consuming.

[00:11:50]But the isopropanol method ensures you don't get colloids. You get all the osmium dioxide out of solution every single time, always.

[00:12:00]And I'm just not going to risk not being able to do so. So, isopropanol it is.

[00:12:08]All right, so what I did this time was I centrifuged the osmium dioxide out of solution.

[00:12:16]Then I let the clear sodium osmate solution boil down a lot. I boiled it down to about right there.

[00:12:23]So, that way I can start adding larger quantities of isopropanol to the solution.

[00:12:31]And hopefully I can start reducing more osmium at a time because I'm adding more alcohol.

[00:12:39]And now I'm boiling it again.

[00:12:42]And reducing more sodium osmates.

[00:12:48]Now you can see a lot of the alcohol boils off pretty quickly.

[00:12:52]Um and then you have more time for the alcohol to react at those temperatures while it's boiling off.

[00:13:02]And the idea is is that hopefully each repetition I can start uh extracting more dioxide per repetition.

[00:13:11]So, that way it hopefully it doesn't take as long.

[00:13:15]Okay, I just added more isopropanol.

[00:13:20]And as you can see it does cause the particles to coalesce.

[00:13:27]As you can see right there, they're coalescing at the interface between the alcohol and the sodium osmate.

[00:13:41]Okay, so here is the next steps. I'm going to be taking this osmium dioxide here and I'm going to be pipetting it into a centrifuge tube.

[00:13:51]This one right here.

[00:13:54]And I'm going to centrifuge it so that way all the osmium dioxide gets plastered nice and flat at the bottom of the tube.

[00:14:02]Then I will take the desired amount of hydrochloric acid, pour it into the tube so that way I'm not diluting the hydrochloric acid.

[00:14:14]So that way when I dissolve it, I can achieve the desired concentration of chloroosmic acid before I go ahead and precipitate the ammonium salts.

[00:14:27]Okay, I did not film the part where I went ahead and I uh stirred up all the dioxide, but I'm going to go ahead and film this part just because.

[00:14:41]All right.

[00:14:43]Let's get the rest of it.

[00:14:50]I keep cycling it like this that way I can get all of it as much as possible.

[00:15:08]Try and wash as much of it down there as possible.

[00:15:15]Try and cycle it out of the pipettes.

[00:15:23]And some of it will inexorably get caught up in the pipette.

[00:15:28]All right.

[00:15:30]Just going to add some more water to this and then we'll be Okay, so I centrifuged it a second time and I'm unable to remove any more water than this.

[00:15:38]So unfortunately, I will be diluting this down a little bit. Hopefully not too much.

[00:15:51]All right. Here we go.

[00:15:58]In it goes.

[00:16:04]And I'm going to cycle it in and there we go.

[00:16:12]All right, so now we start boiling.

[00:16:21]Okay, put the cap on lightly.

[00:16:27]All right.

[00:16:34]Start stirring.

[00:16:36]And turn on the heat for sure.

[00:16:41]All right.

[00:16:43]Let's make our chloro-osmic acid.

[00:16:48]All right, uh still waiting for it to get hotter.

[00:16:51]Some of it may have dissolved already, but still waiting for it to heat up more.

[00:16:57]Can start dissolving more osmium dioxide.

[00:17:01]The platinum analog is much easier to get. All you do is just dissolve platinum metal in aqua regia, but you can't do that with osmium, so have to take the long way around.

[00:17:17]Okay.

[00:17:20]We just take that off the heat.

[00:17:23]All right, and here is our solution of chloroosmic acid.

[00:17:29]It's a nice amber orange color with faint hints of yellow and green.

[00:17:38]Very nice color, actually.

[00:17:40]Okay, now we need to add some ammonium chloride to precipitate the ammonium salts.

[00:17:50]Now, if [clears throat] it doesn't precipitate enough of the salts, then I'm simply going to evaporate again, and then I'll wash it properly this time.

[00:18:03]Not using ethanol, definitely not.

[00:18:07]All right, so I'm going to be adding a fair amount of ammonium chloride this time.

[00:18:13]Going to go ahead and add it in.

[00:18:24]And start precipitating.

[00:18:26]And already we're precipitating it.

[00:18:29]All right, time to get on the stir.

[00:18:31]All right, start stirring.

[00:18:35]Yeah, that's turned very red now.

[00:18:38]Very, very red.

[00:18:43]Very red.

[00:18:46]All right, we just want to dissolve all that ammonium chloride, convert all the osmium to the ammonium salt.

[00:18:53]And then I'm going to centrifuge it to see how much of it I can actually isolate.

[00:18:57]Okay, so I can see a lot of the ammonium salt settling out of solution.

[00:19:02]Um Yeah, it settled right out on the bottom there.

[00:19:07]Let's stir it up.

[00:19:11]Swirl it around a bit.

[00:19:15]And let's just see what happens.

[00:19:18]That is quite a heavy precipitate.

[00:19:21]You can already see it settling at the bottom.

[00:19:26]And yeah, I'll just centrifuge this and see how much of it I can actually isolate.

[00:19:35]That is quite a lot of our very, very red salt.

[00:19:42]Yeah, look at that. There's quite a bit of it in there. It's all settling at the bottom, too. Look at that.

[00:19:48]It's pretty crazy.

[00:19:50]And you can see it right there. It's very red.

[00:19:57]All right. All right.

[00:20:00]Oh, yes, there we have it. That's our ammonium hexachloroosmate.

[00:20:04]All right.

[00:20:07]Now, let's get the rest of this solution back into the vial.

[00:20:22]Okay, and I'm back.

[00:20:25]The centrifuge tube is inside the desiccator bucket.

[00:20:29]And I've got the evaporating dish.

[00:20:33]Okay.

[00:20:35]So, I'm going to take the cap off of this and I'm going to transfer it to the evaporating dish.

[00:20:41]All right. Here we go.

[00:20:57]So, again, we get a nice lemon yellow solution.

[00:21:06]Looks a little darker on the camera, but in real life it actually looks a sort of greenish Yeah, that is a greenish yellow actually.

[00:21:14]Yeah, absolutely. That is definitely a greenish yellow.

[00:21:20]Okay, in you get.

[00:21:27]All righty.

[00:21:28]That's going in the desiccator bucket.

[00:21:31]Okay, so this looked pretty dry and I tried removing some of it.

[00:21:35]I did get a tiny bit out and into a bottle.

[00:21:42]But, it is still wet and it was even wetting the wax paper that I was using.

[00:21:48]So, uh I need to let this dry some more and I don't know what it is about the centrifuge, but whenever I just leave things in here for days on end, they dry out pretty well.

[00:21:58]And this time I'm absolutely [ __ ] determined to get the rest of that out of there and into that bottle just as a consolation prize for myself.

[00:22:07]So, I have added a bunch of sodium hydroxide into this vial next to it because like I said [ __ ] determined to get the rest of it out of there and not losing a bunch of it just because it's wet.

[00:22:23]Okay.

[00:22:26]Rest of this looks like it has dried.

[00:22:30]Okay, so now I feel even more determined to get the rest of it out of there because now I have replaced this tube and this tube with sodium hydroxide. So, now I have three tubes full of sodium hydroxide just to finish drying out this one.

[00:22:52]I am going to get that stuff out of there if it kills me.

[00:22:56]Okay, here it is. This is my consolation prize.

[00:23:02]That is nearly pure ammonium hexachloroosmate and it is indeed a very dark red.

[00:23:12]Um you can compare its color to the cesium salt, which is very orange.

[00:23:22]So, we have cesium hexachloroosmate and ammonium hexachloroosmate.

[00:23:29]Both samples that I'm going to keep.

[00:23:38]Okay. So, now that I've isolated my nice sample of ammonium hexachloroosmate and got a nice, beautiful new picture of it on the Wikipedia page, I no longer care what happens from here.

[00:23:54]If everything goes tits up, that's okay with me cuz I got my sample.

[00:23:58]It's my consolation prize.

[00:24:01]Now, I've got the remainder of the ammonium salt in here.

[00:24:06]If you can see that. Got the camera oddly placed so I can't really tell what's in frame and what's not. So, just as a proof of concept, I'm going to add some deionized water into this, which I have here, and then I'm going to add a little bit of the silver nitrate salt just to see what happens.

[00:24:32]Okay, we should get a sort of very light green, slightly yellow colored solution.

[00:24:39]And when we add the silver nitrate, uh it will produce the insoluble silver hexachloroosmate salt, which is I've read deep brown in color.

[00:24:51]So, even if we can't see any precipitate, the color of the solution should change because we may we may get a colloid.

[00:24:58]But hopefully that colloidal color will be brown.

[00:25:01]So yeah, let's get to it.

[00:25:09]We have a greenish colored solution. If you can see that, there you go. It's a greenish yellow colored solution.

[00:25:16]Let's stick it into this vial.

[00:25:20]All right. If you can see that there's our slightly green yellowish colored solution of ammonium hexachloroosmate.

[00:25:32]All right, and now I'm going to add the silver nitrate to it.

[00:25:40]Tiny little bit of it. See what happens.

[00:25:44]All right, here goes nothing.

[00:25:49]All right, it's in there.

[00:25:53]And look at that. That is Wow.

[00:25:57]Oh my god, there's a lot of it.

[00:26:00]Holy cow.

[00:26:02]Oh, can you see that?

[00:26:04]That is silver hexachloroosmate, if you can believe it. If you can even believe it.

[00:26:11]There it is.

[00:26:12]We made a lot of it. That That's a lot more than I ever expected. Holy cow.

[00:26:17]There it is, folks. That is silver hexachloroosmate.

[00:26:22]Right before your very eyes.

[00:26:26]That is an excellent proof of concept.

[00:26:29]It looks brown.

[00:26:38]But I [ __ ] you not.

[00:26:45]It's actually green.

[00:26:47]It is actually green.

[00:26:52]It's such a dark dark green.

[00:26:58]That is incredible.

[00:27:01]I'm blown away by that.

[00:27:11]Okay, so I was going to wash this ammonium hexachloroosmate evaporate with a 1:1 ratio of saturated ammonium chloride and deionized water with a splash of hydrochloric acid.

[00:27:28]However, uh it would appear that it has already mostly decomposed.

[00:27:35]Um there is a small amount of the red salt left, but the rest of it looks to have decomposed to a sort of blackish substance, which I can assume might be the dioxide, or it is some other form. I don't know.

[00:27:57]But even the crystals have changed color. They've turned dark.

[00:28:01]Um yeah.

[00:28:09]So, I guess I won't be doing anything more.

[00:28:17]Well, that's disappointing.

[00:28:18]Okay, so while it is disappointing that the rest of my ammonium hexachloroosmate decomposed all on its own, what I have here has not decomposed yet.

[00:28:34]It's still perfectly intact.

[00:28:38]It's showing no sign of decomposition whatsoever. It's still very red, and I enjoy it.

[00:28:49]Over here we have the cesium hexachloroosmate ammonium and the silver hexachloroosmate right here.

[00:28:58]And as you can see it still has that pale green color.

[00:29:04]So yeah, three different hexachloroosmates.

[00:29:09]Thank you for watching. I hope you enjoyed.