Lithium-ion batteries are widely used in portable electronic devices and electric vehicles since their introduction by Sony in 1991. Safety is an important concern since about two billion cells are produced every year but with a one-in-200,000 failure rate. Excessive temperature variations and high temperatures over the melting point of the metallic lithium can cause […]
¨The chemical bond¨ is one of the most often used concepts in chemistry. It is also one of the eldest terms since the first definition of chemical bond comes from the studies of G.N. Lewis who published his classical paper on interactions between atoms in 1916 . Lewis stated that ¨ we shall say that […]
Chemistry • Condensed matter • Materials • Physics • Quantum physics
Minimizing losses in any kind of electronic device is always important, but it is paramount in nanoelectronics. Still, most of the phenomena that lead to inefficiencies in the operation of these nanodevices are poorly understood. Consider the case of quantum dots. A quantum dot is a nanometric crystalline structure of semiconductor materials. In a quantum […]
In the standard representation of the periodic table, we find below two separated rows of elements. Their chemistry and electronic configuration belong to a group three element, so what these two separated rows really mean is that in this representation of the table they are all located on top lanthanum and actinium, three-dimensionally building a […]
The role of molecular hydrogen (dihydrogen) in reactions of organic and inorganic chemistry is very well known . One can mention numerous reactions playing the key role in biochemistry, like for example processes in microorganisms, or the commonly known addition of H 2 to organic compounds. It is worth to mention that dihydrogen as an […]
We are all familiar with rust. Rust is an iron oxide, usually red, formed by the reaction of iron and oxygen in the presence of water or air moisture, and it is a clear sign of metal corrosion by oxidation. Oxidation is a ubiquitous phenomenon that proceeds via the electrochemical interaction of ambient oxygen molecules […]
The current in a semiconductor consists of two parts: the negatively charged electrons in the conduction band and the positively charged holes in the valence band. Although the number of electrons in the conduction band is equal to the number of holes in the valence band, the two contributions to the current are in general […]
Organic small molecules are essential for many different fields, from medicine to technology: Most of the drugs we take, biological probes and the constituents of solar cells, to name but a few, are small organic molecules. (Figure 1) However, their synthesis in the laboratory is not easy. Individual reaction conditions for each step of the […]
No matter how the layout of the periodic table may be, there are elements that are always grouped together. This is easy to understand; let’s take for example the standard form of the table (due to H.G. Deming). In this layout each group, each vertical column in the table, has more significant periodic trends than […]
Imagine that you enter a room full of a poisonous gas wearing a mask that is not good enough to prevent the gas reaching your lungs and killing you. The mask is not good enough because it would allow the gas to diffuse through the fabric it is made of, eventually reaching your nose and […]