Subtitles section Play video Print subtitles The element in this video is actually one I have shown you before but this time the element is in a much more aggressive form. Some elements can combine their atoms in different ways. This is called allotropes. Most famous for this is perhaps the element carbon which can form into something as different as graphite and diamond. But this video is about phosphorus. In another video I have shown you the red allotrope of this which is quite reactive but not nearly as much at the white allotrope: white phosphorus. This is a model of a white phosphorus molecule. This shows the so-called ring strain. The bonds are very close and at acute, sharp angles. They really don't like this and want to break loose as illustrated here. So white phosphorus is very reactive because it wants to break it bonds and will for example react so intense with oxygen in the air that it starts burning. I'll show it later. White phosphorus is also so reactive that it turns into red phosphorus over time. The classic way of modeling red phosphorus is shown here. My sample of white phosphorus is not a high purity grade. Some of it has degraded into red phosphorus giving it a yellow appearance. This is often called yellow phosphorus. It's not a separate allotrope - just a mixture of mostly white and some red. Okay. It is time to open the sample but not without the mandatory safety instructions... My point with this clip is: The only safe way to handle white phosphorus is not to handle it all... So just don't. The fire hazard is not the only major problem with white phosphorus. It is also very toxic, even more than fatal thallium - making this one of the most toxic elements. The sample is stored under water to keep the oxygen in the air away from it. Otherwise we would have a fire. White phosphorus is practically insoluble in water but I still wouldn't drink this water. Here it is: 12 g of white phosphorus Even when wet it starts reacting only a few seconds after it is out of the water. You should be able to see some fumes coming from the sample. Don't breathe this. It turns into phosphoric acid with the moisture inside you. Here's a closer look. A large sample like this will not ignite quickly unless the air is hot. I still hold it above some water though because it is rather unpredictable. Looks like this one is getting angrier. Let's move on... Here I scrape of the coating so you better can see the waxy white phosphorus. High-purity white phosphorus is almost glass clear but this is just a commercial-grade yellow sample. Let's cut a small piece of and see if it will catch on fire. Well, it is fuming a lot but not exactly an instant furious fire like you may expect. It even started to melt at some point but I have seen experiments where it took up to 15 minutes before a small sample caught on fire. I am not that patient so I tried if bigger is better with this unpure sample. I will now shut up and show this clip uncut. Have patience and enjoy the show at the end. Wauw, that worked well. What you couldn't see is how much smoke this fire created. It is enough for the military to use it for smoke screens. The flame is almost gone now so I dare to go closer and show how much smoke even this small flame produces. Imagine how much it was when the fire was really raging. The smoke is mostly phosphorus pentoxide and phosphorus trioxide but also phosphine and elemental phosphorus. The oxides react with moisture in the air so the end products are a complicated mixture of polyphosphates. This clearly is a dangerous element but actually it is debatable whether this is my most dangerous element sample. Here are the fire diamonds for thallium, cesium and white phosphorus. 4 is the worst - 0 is no problem. Both cesium and white P maxes out in the blue square - which is about health - so even very short exposure to these two is really bad. In the red square about flammability white P also maxes out because it is pyrophoric and in my opinion cesium should also max out here because it will ignite in moist air. I am not sure about the score of 3 here. Cesium scores the highest of these three in the yellow square about instability because it reacts explosively with water and generally is the most reactive metal. So looking at the fire diamond alone, cesium seems at least as dangerous as white phosphorus. Do you agree? Okay - it is time to pack up and get this sample back to a dark place. It doesn't like a sunny heaven... Let's finish off with something you can try at home. Sparkling wine is fizzy - like soda. They even put a warning sign on the back of this: Don't drink if you're already bloated :) But.. I'm gonna use that fizz for a classic trick. Add mints and it should turn into a champagne geyser. Diet cola is best for this trick but let's try it anyway. Take the cork off... and... add mints... Okay, that's it for now. Thanks for all the subs and remember to click like if you did like.
B2 US phosphorus sample cesium fire element reactive Allotrope from Hell! // My most dangerous element sample? 40 5 許藝菊 posted on 2015/09/18 More Share Save Report Video vocabulary