The only difference between Delta 8 and Delta 9 THC is that the double bond in which a specific carbon atom in the chain has two bonds is placed in different places in the chain. In its chemical structure, Delta 8 has an eighth carbon atom with a double bond; Delta 9 contains a ninth carbon atom with a double bond. Delta-8 THC and delta-9 THC come from the cannabis sativa plant, which naturally produces more than 100 cannabinoids or active components. However, while the plant contains significant amounts of THC delta-9, it contains very little THC delta-8, a minor cannabinoid.
Delta-8 THC is just a different chemical bond from Delta-9 and about half as potent. Since it's technically made from hemp, most states classify it as a hemp product, such as CBD, and allow it to be mailed across state lines without requiring the participation of cannabis regulatory agencies. It doesn't feel as strong as regular marijuana, but it certainly does something, and for those who live in states where cannabis is still illegal, Delta-8 is as close as possible. Others seek it out because of its pleasant, gentle buzz in and of itself.
The only chemical difference between THC Delta 8 and Delta 9 is where a particular double bond is found in the chain of carbon atoms. Delta 8 has a double bond on the eighth carbon atom of its molecular structure; Delta 9 has a double bond on the ninth carbon atom. Although Delta 8 is similar to THC Delta 9, it has a slightly different chemical structure. This difference in chemical structure can mean that it has different effects.