X-ray crystallography explained

7:34Well, usually what we do is we do something called X-ray crystallography. This was um a technique pioneered by William Henry Bragg and his son William Lawrence Bragg. We covered some of the drama there. The fact that William Lawrence Bragg, the son, did all of the math and did all of the actual groundwork, but William Henry Bragg, his father, published a paper about the technique and did not put his son's name on it. And that was a sticking point for his son Lawrence, who always wanted to be called by his middle name because that distinguished him from his father. William Lawrence Bragg and Henry Bragg, they both won the Nobel

8:14Prize in 1915, the only father-son duo to win the same Nobel Prize. And he was 25 at the time, the youngest Nobel Prize winner in the sciences. He went on to be the head of Cavendish Lab at Cambridge and managed the empire that was Cavendish Lab at Cambridge University. The idea is the following: you shoot X-rays at a crystal. >> Yeah. >> The crystal is going to have a lattice structure, meaning all of the atoms are going to be arranged in a very nice regular fashion. Like, we'll we'll see some of the fashions that they're arranged, but in any case, it's like LEGO blocks that are repetitive. And because they're repetitive, the X-rays are going to interfere at certain angles. And if I have a detector on the

8:55end, I can find spots where the X-rays added up and other spots where the X-rays canceled out. And using that pattern, I can discern what is the structure of the crystal inside. >> Mhm. >> Okay? That's the whole game with X-ray crystallography. >> As a crude analogy, is it's almost like making hand puppets with a light source uh yeah, on a wall, and and you're looking at the shadow to determine what is the actual >> exactly. >> figure. >> Yeah, exactly. That's basically it, but in like all three dimensions with like frequency and everything. >> Uh extremely more much more complex. >> Yes, yeah. But at the end of the day, what you can do is through that, you can figure out what is the cubic what is the structure of that crystal inside. And

9:36when we do this with diamond, we figure out that it's a cubic structure. This is what diamond looks like at the atomic scale. >> Mhm. >> Each of these blue orbs is a carbon atom, and each carbon atom is attached to four other carbon atoms in this tetrahedral structure. That orange tetrahedron >> Mhm. >> that is triangles on triangles. There's four triangles that are connected together. It's the first platonic solid that is on our logo right here. And it's a beautiful structure.