Describe the structure of the sulfur molecules in:

b. Monoclinic sulfur

Video transcript

All right. Hi, everyone. So this question is asking us which of the following structures of sulfur is composed of crowns shaped S eight rings at 25 °C. Option A is monoclinic sulfur. Option B is plastic sulfur. Option C is liquid sulfur and option D is rhombic sulfur. Now recall that the answer choices listed are referred to as allotropes of the element sulfur, right? Because sulfur can exist in several allo tropic forms, which means that its atoms can arrange itself for themselves in different ways to produce different physical forms. So let's start with mono clonic sulfur or monoclinic sulfur. Excuse me. So here, right, with monoclinic sulfur, recalled, monoclinic sulfur is composed of S eight rings, but we only observe this allotrope at temperatures above 95 °C. And the reason why we get monoclinic sulfur is when we take rhombic sulfur, which also exists with S eight rings and we subjected to this very high temperature so that the rings themselves are arranged differently. So we do have S eight rings, but monoclinic sulfur is observed at higher temperatures than 25 °C. However, up next, we do have plastic sulfur and recall that plastics are actually polymers, right? So plastic sulfur is referred to as amorphous sulfur because sulfur atoms undergo polymerization. And so what that means is that you're going to end up with these relatively large chains of sulfur atoms that can essentially fold against each other and tangle themselves with each other. So this forms these relatively disordered and and tangled chains of sulfur atoms. So plastic sulfur is the result of polymerization of these larger chains of sulfur atoms interacting with each other. So, not quite what we're looking for, right? Because instead of having chains of sulfur atoms, the question is asking for crown shaped rings. So let's proceed to the next form, which is liquid sulfur. Now recalled, li liquid sulfur is observed at an even higher temperature than monoclinic sulfur because liquid sulfur is found at the temperature range between about 160 °C to 195 °C. So very extreme high temperatures right now, it's at this temperature that the S eight rings actually open, right. So after the S eight rings open this S eight chains for right, because that amount of heat is going to break the bonds in between the S eight rings to form these chains. And so these S eight chains are there going to undergo polymerization, they undergo polymerization in which the broken rings form chains that form even longer polymers of sulfur atoms. And this is observed at a very high temperature. So last but not least is rhombic sulfur and ramic sulfur is precisely the allotrope that we are looking for for this question, right? Because recall that rhombic sulfur is the most stable allotrope of sulfur that exists at 25 °C, which is approximately room temperature, right? It is the form most commonly found in nature and it is composed of crown shaped s eight oops, crown shaped, s eight rings, right? So our answer here is going to be rhombic sulfur, which means that the correct answer is going to be option D in the multiple choice rhombic sulfur is the allotrope of sulfur that is composed of crown shaped s eight rings at 25 °C. So with that being said, thank you so very much for watching and I hope you found this helpful.