So let's recall what anisomer is. So two compounds are said to be isomers, where they have the same exact molecular formula but different structures. So in this lecture, we're going to focus on cystrend ze isomers. So let's begin by looking at the following alkane that has the following molecular formula c two, H two to XY, where XY are simply two different compounds, molecules or atoms that are not H atoms. And let's begin by trying to figure out the three dimensional structure of this alkene. So, alkines have the following structure.