[Music] hi and welcome back to free science lessons by the end of this video you should be able to describe the structure of graphite you should then be able to describe the properties of graphite and Link these properties to its structure in the last video we looked at Diamond which is a giant Cove valent molecule remember that diamond is formed from the element carbon and each carbon atom forms Cove valent bonds to four other carbon atoms because Diamond has a large number of strong coent bonds this makes Diamond a very hard substance if we want to melt diamond then we have to break all of the strong calent bonds and this requires a great deal of energy that means that diamond has a very high melting and boiling point lastly we saw that diamond cannot conduct electricity that's because all of the outer electrons are in calent bonds and there are no free electrons to carry electrical charge in this video we're looking at another form of carbon this is called graphite and graphite is also a giant calent molecule let's start by looking at some of the Key properties of graphite firstly graphite is soft and slippery secondly graphite has a very high melting and boiling point and lastly graphite is a good conductor of both electricity and of heat so let's take a look at the structure of graphite and explain why graphite has these prop properties as I said graphite is formed from the element carbon now in the case of graphite each carbon atom forms Cove valent bonds to three other carbon atoms the carbon atoms form hexagonal rings in other words rings of six carbon atoms and I'm showing you these here the hexagonal rings of carbon atoms are arranged into layers and there are no Cove valent bonds between the layers this means that the layers can slide over each other and this makes graphite soft and slippery graphite is often used as a lubricant in machines reducing friction between the moving parts now graphite contains a large number of strong calent bonds if we want to melt graphite then we need to break those Cove valent bonds and this takes a great deal of energy this explains why graphite has a high melting and boiling point now as I said before graphite is a good conductor of both electricity and heat remember that graphite is formed from carbon atoms I'm showing you the structure of a carbon atom here carbon atoms have four electrons in the outer energy level in graphite each carbon atom forms calent bonds to three other carbon atoms like this however each carbon atom has one electron in its outer energy level that is not in a calent bond these electrons are released from the carbon atoms and scientists call these delocalized electrons I'm showing the delocalized electrons here now the key fact is that these delocalized electrons can move this means that they can conduct both electricity and thermal energy in other words heat now this makes graphite similar to Metals just like graphite metals also have delocalized electrons that can move and like graphite metals are good conductors of both electricity and heat however you need to remember that graphite is formed from the element carbon so Gra fight is not a metal you'll find plenty of questions on this topic in my vision workbook which you can get by clicking on the link [Music] above