Imagine a bucket filled with hard spheres. As these spheres are free to pack together as closely as geometry allows they tend to adopt a close-packed structure, a structure in which there is least unfilled space. X-ray diffraction studies reveal that many metallic elements have close-packed structures. This simple fact explains a couple of very […]
In ‘Chemistry Essentials for Dummies‘, John T. Moore writes: Matter is anything that has mass and occupies space. It can exist in one of three classic states: solid, liquid, and gas. When a substance goes from one state of matter to another, the process is called a change of state, or phase change. As he […]
We usually think of crystals as composed of different atoms in certain proportions, this proportion being the molecular fórmula that represents the crystal. However, it is not surprising that any molecule could be the basis of a crystal structure, whether a simple molecule such as methane, or a complicated molecule such as a protein or […]
Graphene is a two-dimensional allotrope of carbon made of hexagons. It is a zero-gap semimetal with a tiny overlap between valence and conductance bands. Since the isolation of graphene in 2004, considerable interest has been paid to exploring its applications in a variety of fields such as electronics, composites, sensors, catalysis and energy related systems […]
We usually think of nature as existing completely independently of us and possessing a definite reality and behaviour even when we are not observing it. For instance, you assume that the world outside of the place where you are now sitting still exists pretty much as it was when you last observed it. Certainly this […]
The wave–particle dualism is a fundamental aspect of quantum mechanics. But, in order to explore this dualism properly and what it means for our image of atoms, it is necessary to review some ideas of probability. In some situations, no single event can be predicted with certainty. But it may still be possible to predict […]
Condensed matter • Physics • Quantum physics • Theoretical physics
You may have read somewhere that atoms are actually made up mostly of empty space. The usual description goes more or less as follows. At the centre of each atom there is a very tiny nucleus, which carries all of the positive charge and nearly all of the mass of the atom. Surrounding the nucleus […]
Among the group 13 elements, boron alone forms halides of the type X2B-BX2 (X=F, Cl, Br, I), known as tetrahalodiboranes. Over the past five years, the filing of patents involving tetrahalodiboranes has outpaced their appearance in journal articles at a rate of two to one, mostly due to the current interest in B2F4 for the […]
How long does it take a photon to split a molecule? It is apparent that the answer must be well bellow a second, but, how much bellow? Attoscience focuses on these kind of phenomena that occur at the attosecond time-scale using pulses of electrons or photons. The prefix ‘atto-‘, symbol a, means 10-18, hence an […]
During the last decades, the electronics industry has been very successful in pushing forward the advancement of electronic building blocks, but the limit of silicon-based electronic devices especially in terms of miniaturization are almost reached. There are many ideas how to overcome this problem, for example, by adding functionality based on approaches originating from molecular […]