There are six different crystalline forms of chocolate. (Credit: Pexels)


5 surprising things to know about crystals

Crystals form the building blocks of much of our world. Studying them closely lets us understand the structure of biomolecules of things like our bones and muscles, medications, and even chocolate.

Here are five things you might not know about crystals and crystallography:

1. Crystallography takes the prize

The father and son combination of father William Henry Bragg and son William Lawrence Bragg first revealed the structure of salt and won the Nobel Prize in Physics in 1915 for their services “in the analysis of crystal structure by means of x-ray.” So far, the Braggs are the only father and son team to receive a Nobel Prize. In fact, crystallography is the science or discipline directly attributable to winning the most Nobel Prizes, taking the award 28 times.

X-ray crystallography has developed at a rapid pace in the last 20 years. Scientists first used the technique over 100 years ago when they determined the crystal structure of salt.

In essence, the method involves placing a tiny crystal in the path of an x-ray beam. As the x-ray passes through the crystal, the radiation is diffracted into a pattern by the atoms that make up the molecules in the crystal structure.

The diffraction pattern is like a fingerprint that identifies not only the nature of the atoms and bonds in the molecules, but also their three-dimensional arrangement. It is the only analytical method that can achieve this level of analysis in such a complete and unambiguous fashion.

2. Around 90 percent of all drugs are crystals

That’s because it’s much easier to control the solid state of a crystalline structure—even using a gel would involve crystals that are suspended in a gooey substance to aid the delivery of the drug involved. Some drugs that are injected would also be comprised of small crystals as crystalline materials can be arranged in different ways, under different conditions, to create the required effect.

If you take a tablet, it has to dissolve in your gut and get across the gut wall into the bloodstream. How the crystals in the drugs are composed will define how readily they will dissolve in your gut. If you get the wrong form, the drug might go all the way through the body, or dissolve in the wrong place and be useless.

3. They’re in our eyes and bones

For example, most of the rods and cones in your eye that conduct the light or form an image are made of crystals. Around 65 percent of the bone mass of an adult is made of hydroxyapatite crystal.

4. Chocolate is crystalline

The National X-ray Crystallography Service at the University Southampton has done a number of experiments on the crystalline structures of chocolate. The cocoa butter added controls the crystallinity and that is important because there are six different crystalline forms of chocolate.

The one that most chocolate wants to be—the most stable form—is the unappetizing one with the white coating on the top. Playing around with the amount of cocoa butter affects the crystalline nature of the chocolate, which is how to get different forms, tastes, and textures.

5. We owe fireworks to crystals

The problem with explosive powders, or other substances like nitroglycerine, is their volatility. However, if they were to be created in a more stable solid state, they would be safer to transport and easier to control.

One solution, discovered at the University of Southhampton, is to move toward a different kind of high-energy material by growing crystals with firework-type properties in a scaffold or lattice-like structure, which stays stable. The material features channels and voids where different dyes can create different colors. Putting nitroglycerine within such a structure would allow it to stay stable longer.

The applications for this kind of firework are not just for entertainment or defense. The airbags in our cars are also initiated by energetic materials that are all mini fireworks, so there are many civilian applications for these crystals as well.

Source: University of Southampton

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