Singlet

Free radicals are produced by a variety of normal biological processes including aerobic metabolism and pathogenic defense mechanisms. They can also be a result of external exposures such as radiation, pollutants, and cigarette smoke. Reactive oxygen species, or ROS, are a subset of free radicals that contain oxygen. Is oxygen considered a free radical? Oxygen […]

Oxygen as a free radical Probably the most well-known free radical, oxygen is the basis for development of most free radicals in the body. Inherently, oxygen is an unstable molecule. What’s the difference between free radicals and oxygen? Free radicals are produced by a variety of normal biological processes including aerobic metabolism and pathogenic defense […]

In the nonpolar environment of membranes, CO2 supports free radical reactions and can accentuate the ensuing oxidative damage. Under physiological pH, hydrolysis proceeds faster. In this way, anions act as scavengers of N2O3 preventing the nitration reactions. What are examples of free radicals? Examples of Free Radicals Superoxide anion radical. Hydrogen peroxide. Hypochlorite. Nitric oxide […]

O2+>O2>O2−>O22− Which is more stable O2 O2+ O2? Solution : Bond order of `O_(2)^(+) = 2.5 `, Bond order of `O_(2)^(-)m = 1.5 . Hence, O_(2)^(+)` is more stable than `O_(2)^(-)` . What the order of stability for the molecules is? Bond order normally gives idea of stability of a molecular species all the molecules […]

triplet state. Answer: The triplet state is always more stable than the singlet state. This is because, in a triplet state, the spins of the two electrons are parallel while in a single state, the spins of the two electrons are antiparallel. Which is more stable singlet or triplet? Due to the unavailability of vacant […]

In mathematics, a prime triplet is a set of three prime numbers in which the smallest and largest of the three differ by 6. In particular, the sets must have the form (p, p + 2, p + 6) or (p, p + 4, p + 6). What is prime triplet number example? A prime […]

Oxygen as O2 is stable enough to be abundant in the environment and is required for many forms of life. But from the standpoint of theory, dioxygen’s stability is curious: Its highest occupied molecular orbitals contain two unpaired electrons, making it a diradical. Is oxygen a diradical? Ground state oxygen is a diradical, which explains […]

Reaction. The unusual electron configuration prevents molecular oxygen from reacting directly with many other molecules, which are often in the singlet state. Triplet oxygen will, however, readily react with molecules in a doublet state to form a new radical. What is the triplet state of oxygen? The first configuration has a multiplicity of 3 (hence […]

carbene, any member of a class of highly reactive molecules containing divalent carbon atoms—that is, carbon atoms that utilize only two of the four bonds they are capable of forming with other atoms. Why are carbenes reactive? Carbenes 1 are species bearing a divalent carbon. In their singlet state, they possess a lone pair and […]

Phosphorescence is light energy produced by a particular type of chemical reactionwhere the excess chemical energy of the reactants is given off as light energy. Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. What is the difference between the fluorescence […]

There are various definitions of fluorescence and phosphorescence with the simplest being that fluorescence is prompt photoluminescence that occurs very shortly after photoexcitation of a substance, while phosphorescence is long-lived photoluminescence that continues long after the photoexcitation has ceased. What is difference between fluorescent and fluorescence? People often refer to lights for bringing out (exciting) […]

In this meaning, the material is said to be unstable if it can corrode, decompose, polymerize, burn or explode under the conditions of anticipated use or normal environmental conditions. How do you know if a compound is unstable? Usually, this can be known by comparing the preferred state of the element or compound to its […]

Carbenes that formally derive from imidazole-2-ylidenes by substitution of sulfur, oxygen, or other chalcogens for both α-nitrogens are expected to be unstable, as they have the potential to dissociate into an alkyne (R1C≡CR2) and a carbon dichalcogenide (X1=C=X2). Is carbene unstable? MHC is a carbene, a family of highly reactive molecules containing carbon atoms that […]

When a singlet state nonradiatively passes to a triplet state, or conversely a triplet transitions to a singlet, that process is known as intersystem crossing. In essence, the spin of the excited electron is reversed. What is singlet and triplet transition? In an excited singlet state, the electron is promoted in the same spin orientation […]

Phosphorescence is emission of light from triplet-excited states, in which the electron in the excited orbital has the same spin orientation as the ground-state electron. Transitions to the ground state are spin-forbidden, and the emission rates are relatively slow (103 to 100 s−1). Which of the following transition is involved in phosphorescence? Phosphorescence: Deactivation of […]

Fluorescence is an underlying optical phenomenon that is commonly used in biosensors. Fluorescence occurs when a fluorescent atom absorbs a photon of high energy which excites an electron into one of the many higher energy states. What is chemical excitation? Illustrated Glossary of Organic Chemistry – Excitation. Excitation: The process of changing from a ground […]

Toxicity of O Oxygen can be toxic at elevated partial pressures. Since oxygen partial pressure is the fraction of oxygen times the total pressure, elevated partial pressures can occur either from high oxygen fraction in breathing gas, or from high breathing gas pressure, or a combination of both. Can we breathe singlet oxygen? Traditionally, oxygen […]

Since animals (including humans) breathe molecular oxygen and require it for metabolism, it is important medically. Molecular oxygen is provided therapeutically in oxygen therapy and hyperbaric chambers, and is also included in breathing gas for space exploration and SCUBA diving. Can we breathe singlet oxygen? Traditionally, oxygen therapy is done by breathing air with high […]

ROS/RNS can cause cell death by nonphysiological (necrotic) or regulated pathways (apoptotic). The mechanisms by which ROS/RNS cause or regulate apoptosis typically include receptor activation, caspase activation, Bcl-2 family proteins, and mitochondrial dysfunction. How does ROS cause cell damage? Reactive oxygen species (ROS) can cause damage to the basic building blocks of the cell including […]

ROS are well recognized as mediators of DNA damage. For example, Ionizing Radiation (IR) induces DSBs through direct high-energy damage to the sugar backbone of DNA, but also through free radicals generated in cells- mostly •OH from water [22]. How does ROS cause damage? Reactive oxygen species (ROS) can cause damage to the basic building […]