Ciencias Sociales España , Salamanca, Lunes, 19 de mayo de 2014 a las 17:27

The vast world of crystals

Studying crystals has several applications in fields like Medicine, Geology or Agriculture and the University of Salamanca counts on many research groups that are going to participate of the International Year of Crystallography

José Pichel Andrés/DICYT Most of things which are around us are made of crystals, although, paradoxically, we only call crystal one of the fewest solid matters which, technically, is not one: it is glass, with which windows are made, for example. 2014 is the International Year of Crystallography and the scientists who study this discipline come to this celebration as a great opportunity to explain to society that crystals are a part of our bodies, of the objects which surround us and of nature; and that their studies offer a vast list of applications. At the University of Salamanca, researchers of different subjects like Inorganic Chemistry, Pharmacy, Geology and some of those who work at the Cancer Research Center are related to Crystallography.


“Crystals are everywhere, in an organic world as well as in an inorganic one, and they are essential for life”, explains to DiCYT Mercedes Suárez, director of the Geology Department of the University of Salamanca. “A crystal is a solid which has a specific structure”, clarifies. In particular, in a crystal “all atoms, ions or molecules are organized in three space dimensions”. Sometimes this organized structure becomes visible, like the snow, which, in detail, looks like a kind of star with many points and with a shape that has a strict order.


Actually, there are very few solids that are not organized, but one of them is glass, formed by silica, whose structure is disorganized. Nevertheless, it cannot be considered a crystal. On the contrary, the examples of crystals and their omnipresence are innumerable. “If we analyze a mineral like calcite, all the calcites in the world are organized in the same way, the ones that can be found in a chicken’s eggshell, in the marble of Michelangelo’s statue of Moses or in the lime-filled rocks of European Peaks, all of them contain calcium and carbonate which make the calcites up in the same positions”, says the expert. Inside a human body, the bones and the teeth are made up of phosphates, which are also crystals.

One of the reasons why the United Nations General Assembly has proclaimed 2014 the International Year of Crystallography is because it is the 400 anniversary of symmetry observation in ice crystals by Kepler in 1611. The other reason is that it is 100 years of X-ray diffraction as a tool for the study of crystalline matter. In a diffractometer one can analyze any crystalline solid. The X-rays provide information about the kind of atoms which can be found in their way; this way, one can determine the tridimensional structure of molecules and know how the crystal one is studying is. In order to do it, the University of Salamanca counts on General Service of X-Ray Diffraction of the Research Support Platform NUCLEUS and with other diffractometers of many research groups.

Curiously, every year in the world from 10 to 20 new minerals are discovered and to validate those findings one has to demonstrate its composition, its structure or that both things are different from other previously registered minerals. As far as the structure is concerned, the X-ray diffraction is essential.

 

“In my case, I work with special clays which can be commercialized”, exemplifies Mercedes Suárez. “Their properties vary a lot due to crystal chemistry and how a crystal really is in detail, up to a level in which among the natural deposits of the same mineral and a purity near 100%, it is possible that one is not good for a specific application and the other is exceptionally good for the same thing”, comments.

In their most spectacular shapes, the giant crystals of Naica cave in Mexico may have more than 10 meters of length and an astonishing beauty. On the other hand, a human being is capable of synthesizing perfect pieces of jewellery with a chemistry composition and a crystalline structure like natural gems like diamonds, though without the crystalline defects typical of nature.

 

Applications

 

Crystallography’s practical applications are essential to many sectors, like the pharmaceutical one. “A drug tends to be composed by powder and taken in capsules or tablets, in a way that medicine is composed by small crystals of a certain substance, and when designing new medicine, one has to know the structure of this specific compound”, explains. That is the reason why biomedical researchers like the ones at the Salamanca Cancer Center are familiar with this field of knowledge.

The same thing happens when new materials are designed and even in the conservation of historical heritage. To know how the stones in a monument are altered, one has to analyze the crystallization of the salts that are damaging them. Something similar happens with paintings, from a picture to a prehistoric cave. In a very distinct field, even the fertilizer design for agriculture needs to resort to this discipline.


“The studies about Crystallography do not seem more than basic science, but, in fact, they are related to aspects of our daily lives, there are many scientists working in this area to improve everybody else’s lives”, points out Mercedes Suárez.

 

Diffusion

 

In order to show this very wide field of knowledge, the Geology Department and the Scientific Culture Space of the University of Salamanca have prepared an exposition for the beginning of the next academic course. On one hand, the idea is to explain what Crystallography consists of. On the other hand, the second objective is to make society aware of the research groups of the academic institution that are related to this subject, which encompasses from geology to health.


In Spain, there are many research groups dedicated to Crystallography recognized worldwide. That is the case of Cristóbal Viedma, whose studies “have caused a revolution to synthesize certain kinds of drugs”, although he is “a geologist who studies Crystallography in a very modest lab”.