Europium(II) sulfide

Transcription

Greetings fellow nerds. In upcoming videos we're going to need the europium and dysprosium nitrate salts, more specifically the pentahydrate forms. We've given this procedure it's own separate video to make the upcoming videos shorter and more to the point. Pure europium and dysprosium metal can be purchased from online element dealers. There very popular for element collectors, and a few will sell directly to individuals. This makes europium and dysprosium nitrate very accessible to non-scientists. Look in the video description for the links. Alright, let's first start with europium nitrate. Here we have a 2.5 gram sample of pure europium metal. Europium metal is highly reactive even toward air, so when you buy it the europium will come stored in mineral oil. Carefully take it out with tweezers and wash it thoroughly in some toluene to get rid of the mineral oil. Hold it in the air for a few minutes to dry it out. Then place it in a beaker. As you can see, it's already starting to react with the air to produce that yellowish white oxide layer. Now carefully pour in a total of 10 mL of pure distilled water. As you can see, europium metal is highly reactive toward water, about the same level as calcium. As it reacts, it produces europium hydroxide that covers the metal and slows down the reaction. When the reaction seems to have stopped, carefully add in a total of 10 mL of concentrated 15.6 molar nitric acid in small portions. Let the mixture react until it's just bits of dust left over. Now carefully heat the mixture until it boils and completely dissolves the metal. Now we have a pure solution of europium nitrate with excess nitric acid. We'll make this into a powder in a moment. But now, let's do dysprosium nitrate. Here is a 5 gram sample of dysprosium metal. Place it in the beaker and then add 20 mL of pure distilled water. As you can see, dysprosium is much less reactive than europium. To get it going, directly add 20 mL of concentrated 15.6 molar nitric acid. As it reacts it will produce nitrogen dioxide. Once again, let it react until it's just a suspension of metal particles. Then boil it until it completely dissolves. Now you have a yellow solution of pure dysprosium nitrate with nitric acid. Now place both nitrates into the desiccator bag we made in a previous video. You cannot simply boil them down because these nitrates are so sensitive that they'll decompose if heated to dryness. You also cannot simply leave them out to evaporate because they're extremely hygroscopic and almost never crystallize out of solution. Alright, after a few weeks in the bag with the occasional mash up to expose any pockets of moisture, take out the nitrates. Make sure they're dry enough by crushing them and seeing if they crumble to a powder rather than a paste. If they are dry, transfer them into vials with air tight caps. Remember to clearly label the vials. After years of being a sloppy chemist I learned this important lesson the hard way. Anyway, here we have our finished rare-earth europium and dysprosium nitrates. We're specifically going to use them for their metal component in some very cool upcoming videos so please subscribe, rate and comment.