• The complete balanced reactions for each step should be written showing the transfer of electrons during oxidation and reduction. (wardsci.com)
  • These reactions involve the transfer of electrons between chemical species and are ubiquitous in nature and synthetic chemistry. (mometrix.com)
  • Thus, the species that has been oxidized is also called the reducing agent because it provides the electrons for reduction. (mometrix.com)
  • Similarly, the species that is reduced is called the oxidizing agent because it takes the electrons for oxidation to occur. (mometrix.com)
  • However, in unfamiliar and more complex reactions, it becomes challenging to follow the flow of electrons. (mometrix.com)
  • But by tracking the change in oxidation numbers, we can follow the flow of electrons in a chemical reaction. (mometrix.com)
  • The more current there is, the faster the electrons are flowing and the higher the rate of the reaction must be. (siyavula.com)
  • A chemical reaction that involves the gaining of electrons by one of the atoms involved in the reaction between two chemicals. (helpteaching.com)
  • A chemical reaction that occurs in an atom or compound and results in the loss of one or more electrons. (helpteaching.com)
  • Electrochemistry studies oxidation-reduction reactions, which were first discussed in an earlier chapter, where we learned that oxidation was the loss of electrons and reduction was the gain of electrons. (pressbooks.pub)
  • Oxidation is the loss of electrons or loss of hydrogen and addition of oxygen. (scienceaid.net)
  • Reduction is the gain of electrons or gain of hydrogen and loss of oxygen. (scienceaid.net)
  • S-block metals loose their electrons in a reaction, so are good reductants (they are oxidized easily). (scienceaid.net)
  • and those in group VII, gain electrons in reactions so are good oxidants (they gain electrons easily). (scienceaid.net)
  • Al 2 O 3 + 2Fe In this reaction iron is reduced (is an oxidant) because it gains electrons and goes from ion to element. (scienceaid.net)
  • The main difference between oxidation and reduction electrochemical reactions is that oxidation involves the loss of electrons , whereas reduction involves the gain of electrons. (pediaa.com)
  • Basically, oxidation is a process in which a chemical species loses electrons. (pediaa.com)
  • This reduction in the number of electrons surrounding the species leads to an increase in its oxidation state . (pediaa.com)
  • In a typical battery, one electrode undergoes oxidation, releasing electrons, while the other electrode undergoes reduction, accepting those electrons. (pediaa.com)
  • For instance, in a zinc-carbon battery, the anode consists of zinc, which undergoes oxidation to form zinc ions and release electrons. (pediaa.com)
  • Reduction is a fundamental process in electrochemistry where a chemical species gains electrons. (pediaa.com)
  • Oxidation and reduction reactions involve redox pairs, consisting of a species that gets oxidized (loses electrons) and another that gets reduced (gains electrons). (pediaa.com)
  • Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. (wikipedia.org)
  • For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. (wikipedia.org)
  • Thus, in the reaction, the reductant or reducing agent loses electrons and is oxidized, and the oxidant or oxidizing agent gains electrons and is reduced. (wikipedia.org)
  • Ultimately, the meaning was generalized to include all processes involving the loss of electrons or the increase in the oxidation state of a chemical species. (wikipedia.org)
  • The meaning of reduction then became generalized to include all processes involving a gain of electrons. (wikipedia.org)
  • In redox reactions, one molecule (the reducing agent) loses electrons and the other molecule(the oxidizing agent) accepts electrons. (kenyon.edu)
  • The oxygen atoms undergo reduction , formally gaining electrons, while the carbon atoms undergo oxidation, losing electrons. (moviecultists.com)
  • During oxidation, there is a transfer of electrons . (moviecultists.com)
  • In other words, during oxidation, there is a loss of electrons. (moviecultists.com)
  • There is an opposite process of oxidation known as a reduction in which there is a gain of electrons. (moviecultists.com)
  • Oxygen is reduced by gaining electrons, and in reaction with hydrogen ions, water, the only byproduct of a fuel cell reaction, is produced. (sciencedaily.com)
  • With the Oxidation-Reduction Basics Student Chemistry Laboratory Kit, students investigate reactions to determine the relative tendency of metals to lose electrons. (flinnsci.com)
  • Students investigate reactions between various metals and metallic ion solutions to determine the relative tendency of metals to lose electrons. (flinnsci.com)
  • In the oxidation number change method the underlying principle is that the gain in the oxidation number (number of electrons) in one reactant must be equal to the loss in the oxidation number of the other reactant. (periodni.com)
  • The electrons lost in the oxidation half-reaction must be equal the electrons gained in the reduction half-reaction. (periodni.com)
  • Learners should be able to predict whether an electrode is the anode or cathode depending on the half-reaction taking place there. (siyavula.com)
  • They must also know which half-reaction will take place at the anode and which will take place at the cathode. (siyavula.com)
  • They should realise that the table provided is for the reduction half-reactions and that the oxidation half-reaction table would have the reactions reversed and the \(E^{\circ}\) V value with the opposite sign. (siyavula.com)
  • 2. What is the reduction half-reaction for the following unbalanced redox equation? (questions.llc)
  • Electron Transfer Theory Write an label the oxidation and reduction half-reaction equations. (questions.llc)
  • What is the reduction half reaction for this redox reaction? (helpteaching.com)
  • The half-reaction method splits oxidation-reduction reactions into their oxidation "half" and reduction "half" to make finding the overall equation easier. (pressbooks.pub)
  • Fe2+ / Fe3+ .The oxidation alone and the reduction alone are each called a half-reaction because two half-reactions always occur together to form a whole reaction. (wikipedia.org)
  • Balance the atoms in each half reaction. (periodni.com)
  • The sum of oxidation numbers for the atoms within a compound must equal the charge of the compound. (mometrix.com)
  • By assigning the oxidation numbers to each species, we can see that the sodium atoms were oxidized because their oxidation number increased whereas the chlorine atoms were reduced because their oxidation number decreased. (mometrix.com)
  • The oxidation gives a compound its name, for example Iron (IV) oxide means the oxidation state of iron is 4 so therefore there must be two oxygen atoms bonded to it. (scienceaid.net)
  • A related method of reduction involves the use of hydrogen gas (H2) as sources of H atoms. (wikipedia.org)
  • A chemical reaction, for instance, involves the creation of substances different from those that reacted in the first place, but the number of atoms involved does not change. (scienceclarified.com)
  • In summary, redox reactions can always be recognized by a change in oxidation number of two of the atoms in the reaction . (moviecultists.com)
  • Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties. (flinnsci.com)
  • Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction. (flinnsci.com)
  • This results in a decrease in the oxidation state of the species, and it is often associated with the formation of negatively charged ions or anions. (pediaa.com)
  • This section is a more indepth look at the oxidation and reduction reactions taking place at the anode and cathode in electrochemical cells. (siyavula.com)
  • The learners should understand the processes involved, but do not need to memorise the exact reactions, and need not study the industries themselves. (siyavula.com)
  • These reactions are crucial in various processes, from powering batteries to driving chemical reactions in living organisms. (pediaa.com)
  • Oxidation reactions are even central to many chemical synthesis processes. (pediaa.com)
  • The processes of oxidation and reduction occur simultaneously and cannot occur independently. (wikipedia.org)
  • The electrochemist John Bockris proposed the words electronation and deelectronation to describe reduction and oxidation processes, respectively, when they occur at electrodes. (wikipedia.org)
  • To begin with, all combustion processes involve oxidation (some possible exceptions) but not all oxidation reaction are combustion. (moviecultists.com)
  • We postulate that: (i) 3HKG may be able to photoinitiate free radical reactions in vivo, and (ii) oxygen is an important factor determining the yields of free radical processes initiated by lenticular chromophores. (nih.gov)
  • In this project, detailed single particle models for the thermo-chemical conversion (reduction and oxidation) of micro-sized particles will be developed in order to identify and model rate-controlling processes depending on the following influencing factors: Ambient conditions (temperature, composition of the gas atmosphere) and particle properties (particle size, porosity, etc. (tu-darmstadt.de)
  • For reduction and oxidation, the reactions and their coupling to transport processes must first be understood for individual particles, since both heat and mass transfer between particles and the surrounding gas phase and the kinetics of the heterogeneous surface reaction can potentially be rate-determining processes. (tu-darmstadt.de)
  • In this subproject, a detailed single particle model for the thermo-chemical conversion (reduction and oxidation) of micro-sized particles will be developed in order to identify and model rate-controlling processes depending on the above-mentioned influencing factors. (tu-darmstadt.de)
  • Phenomena such as the ORR surface structure sensitivity and the lack of a reduction current at high potentials are discussed in the light of the surface oxidation and disordering processes and the possible relevance of the hydrogen peroxide reduction and oxidation reactions in the ORR mechanism. (beilstein-journals.org)
  • Therefore other approaches are needed that include theoretical calculations that could help to shed light on the microscopic structures and processes taking place at the surface during the reaction. (beilstein-journals.org)
  • Two of the most common pyrometallurgical processes, in both extraction and refining, are oxidation and reduction. (britannica.com)
  • to cover key concepts in chemical reaction kinetics and redox processes. (manchester.ac.uk)
  • These coenzymes play a necessary role in most of the major energy-producing biochemical processes in the body, acting as electron carriers for enzymes in oxidation-reduction reactions. (medscape.com)
  • Classify each of the following unbalanced half-reactions as either an oxidation or a reduction. (pearson.com)
  • A redox reaction consists of either an oxidation reaction or a reduction reaction. (pr.com)
  • MLA (Modern Language Association) "Redox Reactions: Oxidation and Reduction, Oxidation States and Redox Equations. (scienceaid.net)
  • It is used primarily in chemical equations when describing oxidation and reduction, or redox reactions. (wikiversity.org)
  • The development of the particle structure (degree of oxidation, porosity development) is basically opposite for reduction and oxidation, but can be described mathematically almost analogously. (tu-darmstadt.de)
  • How do the total reduction or total degree of oxidation and the distribution of oxidation states in the particle behave as a function of time? (tu-darmstadt.de)
  • The oxidation state of simple ions is simply its charge. (scienceaid.net)
  • The sum of the oxidation states in polyatomic ions is always the charge on the ion. (scienceaid.net)
  • Oxidation is often associated with the formation of positively charged ions or cations. (pediaa.com)
  • It relies on oxidation and reduction reactions to selectively transfer metal ions from a solution to a substrate. (pediaa.com)
  • Furthermore, reduction plays a central role in electrolysis , as it involves the deposition of metal ions onto a surface ( electroplating ) or the production of gases (e.g., hydrogen and oxygen) through the reduction of water. (pediaa.com)
  • The process of photoreduction may overcompensate the aerobic oxidation resulting in the presence of ferrous (Fe2+) ions during daylight and disappearing during the night (Kopácek et al 2005). (europa.eu)
  • The reaction starts with the fully reduced form of the enzyme, presumably with a water molecule weakly coordinated to the type-2 copper (Cu-T2) ion and no bridging moiety between the two type-3 copper (Cu-T3) ions.17,22 The incoming di- oxygen is immediately reduced, yielding a peroxide-level intermediate (PI),12 with a peroxide ion bound in the centre of the TNC. (lu.se)
  • So, chemists assign an oxidation number (known as "O.N." or "oxidation state") to each atom, which generally reflects how electron-rich or -poor that atom is. (mometrix.com)
  • Because of this assumption, oxidation numbers do not represent the actual charge on an atom. (mometrix.com)
  • The oxidation number of a Group 7A(17) element in a compound is -1 unless it is paired with an atom with a larger electronegativity, in which case, it takes on a value to balance the charge of the compound. (mometrix.com)
  • What would the oxidation number of a xenon atom be, and what would this oxidation number suggest? (helpteaching.com)
  • The reactions discussed tended to be rather simple, and conservation of mass (atom counting by type) and deriving a correctly balanced chemical equation were relatively simple. (pressbooks.pub)
  • Oxidation state of an atom in element is 0. (scienceaid.net)
  • There are two classes of redox reactions: Electron-transfer - Only one (usually) electron flows from the atom being oxidized to the atom that is reduced. (wikipedia.org)
  • Hydride transfer reagents, such as NaBH4 and LiAlH4, reduce by atom transfer: they transfer the equivalent of hydride or H−. These reagents are widely used in the reduction of carbonyl compounds to alcohols. (wikipedia.org)
  • It is also defined as reaction in which there is loss of electron from an atom or ion. (moviecultists.com)
  • Oxidation state refers to the overall charge on an atom or molecule. (wikiversity.org)
  • The oxidation state is the total charge which all the bonds of the particular atom generate considering their electronegative value. (wikiversity.org)
  • Considering every bond you can make this calculation , which results in the total Oxidation State of the atom. (wikiversity.org)
  • a) Assign oxidation numbers for each atom in the equation. (periodni.com)
  • Metals can undergo oxidation when exposed to oxygen and moisture, leading to the formation of rust or other corrosion products. (pediaa.com)
  • This process is the complementary half of a redox (reduction-oxidation) reaction , where one substance undergoes oxidation while another simultaneously undergoes reduction. (pediaa.com)
  • Undergoes various addition, reduction, and oxidation reactions. (sigmaaldrich.com)
  • Oxidation is an exothermic reaction, meaning it gives releases heat energy. (moviecultists.com)
  • It is an exothermic reaction which releases heat and light as energy forms. (moviecultists.com)
  • The learners should understand that the electrode potentials in the table of standard electrode potentials are relative electrode potentials, and allow us to compare different metals without having to set up a new reaction each time. (siyavula.com)
  • Our team's research raises promising possibilities for synthesizing improved platinum-based catalysts and for stabilizing platinum and platinum-group metals under cycling oxidation/reduction conditions. (sciencedaily.com)
  • For example, the oxidation state of Mg 2 + is +2, however, we also assign oxidation states to other compounds and the charge it would have if it were a simple ion and not bonded. (scienceaid.net)
  • In order to work out the oxidation states of some compounds we need to use some rules. (scienceaid.net)
  • This perspective focuses on two areas that have yielded new useful information during the last 20 years: (i) structure-activity relationship (SAR) studies of contact allergy based on the concept of hapten-protein binding and (ii) mechanistic investigations regarding activation of nonsensitizing compounds to contact allergens by air oxidation or skin metabolism. (cdc.gov)
  • Many compounds are not allergenic themselves but are activated in the skin (e.g., metabolically) or before skin contact (e.g., via air oxidation) to form skin sensitizers. (cdc.gov)
  • The clinical importance of air oxidation to activate nonallergenic compounds has been demonstrated. (cdc.gov)
  • mechanistic investigations regarding activation of nonsensitizing compounds to contact allergens by air oxidation or skin metabolism. (cdc.gov)
  • This section introduces the concept of an electrochemical reaction, it may be worth a brief revision of the zinc-copper experiment performed in Grade 11. (siyavula.com)
  • Oxidation and reduction are fundamental concepts in electrochemical reactions. (pediaa.com)
  • Using x-rays as probes at Brookhaven's National Synchrotron Light Source, a scanning transmission microscope at Brookhaven's Center for Functional Nanomaterials, and electrochemical techniques in the laboratory, the scientists were able to verify the reduced oxidation of platinum and to determine the structure of the resulting platinum electrocatalyst with gold clusters, which helped them to gain an understanding of the effects of the gold clusters. (sciencedaily.com)
  • Electrochemical studies of the Nafion/Bi-modified CSPE indicated a diffusion-controlled redox reaction for Co and Ni measurements. (cdc.gov)
  • Learners should understand that when a cell is flat the reactions inside are in equilibrium and the concentration of the reactants and products are constant. (siyavula.com)
  • Many reactions move to their conclusion and then stop, meaning that the reactants have been completely transformed into products, with no means of returning to their original state. (scienceclarified.com)
  • Identify which reactants are being oxidized (the oxidation number increases when it reacts) and which are being reduced (the oxidation number goes down). (periodni.com)
  • Reactions are the "verbs" of chemistry-the activity that chemists study. (scienceclarified.com)
  • In water containing oxygen, the chemistry is dominated by iron-oxygen reactions. (europa.eu)
  • A team of researchers from Lund University involving researchers at the Theoretical Chemistry Division have developed and characterized the first photofunctional iron molecule capable of both emitting light that can be seen by the naked eye, as well as to drive light-induced bimolecular oxidation and reduction reactions. (lu.se)
  • Let's walk through a redox reaction with a familiar product, sodium chloride, which can be formed from sodium metal and chlorine gas. (mometrix.com)
  • Given what we've just learned about redox reactions, we can now say that because sodium loses an electron, it is oxidized, and because the chlorine gains an electron, it is reduced. (mometrix.com)
  • So, in our example, our sodium metal and chlorine gas both have an oxidation number of 0. (mometrix.com)
  • In our case, chlorine is paired with sodium, which has a much lower electronegativity, so chlorine has an oxidation number of -1. (mometrix.com)
  • We can also say that sodium acts as the reducing agent and chlorine acts as the oxidizing agent in this reaction. (mometrix.com)
  • What is the oxidation number of chlorine in [math]KClO_4[/math]? (helpteaching.com)
  • To assign oxidation numbers, we'll need to learn a set of rules. (mometrix.com)
  • Let's start by learning the ones necessary to assign the oxidation numbers for the formation of sodium chloride. (mometrix.com)
  • This rule applies to sodium in sodium chloride, so we can assign a +1 oxidation number to sodium. (mometrix.com)
  • The term oxidation can mean the chemical combination of a substance with oxygen and reduction can be the removal of oxygen from a compound. (wardsci.com)
  • The oxidation number of a Group 1A element in a compound is +1. (mometrix.com)
  • In our example, sodium chloride is the only compound, and it has an overall charge of 0, which checks out because the oxidation numbers for Na, +1, and Cl, -1, do indeed sum to 0. (mometrix.com)
  • What represents the total oxidation state for an ionic compound? (helpteaching.com)
  • Combustion is the complete oxidation of organic compound into carbon dioxide and water molecules in presence of oxygen gas whereas oxidation is the addition of oxygen in a compound or addition with an element. (moviecultists.com)
  • Often, this type of regeneration uses an oxidation catalyst, such as platinum, vanadium or similar compound, to reduce the temperature necessary to begin regeneration. (cdc.gov)
  • Redox (/ˈrɛdɒks/ RED-oks, /ˈriːdɒks/ REE-doks, reduction-oxidation or oxidation-reduction) is a type of chemical reaction in which the oxidation states of substrate change. (wikipedia.org)
  • Redox reactions are titled as such because during the reaction one chemical species is oxidized while another is simultaneously reduced . (mometrix.com)
  • A redox reaction is nothing but both oxidation and reduction reactions taking place simultaneously. (periodni.com)
  • Changes in the oxidation state of terminal electron acceptors may result in nutrient loss from the system via volatilization or leaching. (kenyon.edu)
  • 58 exposed to the allergen in a concentration exceeding the Oxidation individual threshold. (cdc.gov)
  • This type of redox reaction is often discussed in terms of redox couples and electrode potentials. (wikipedia.org)
  • In a combustion reaction oxygen is combined with the fuel source usually carbon and hydrogen based resulting in carbon dioxide and water and so this is an oxidation reaction. (moviecultists.com)
  • An oxidation reaction occurs when oxygen is coupled with a fuel source, which is commonly carbon or hydrogen based, to produce carbon dioxide and water. (moviecultists.com)
  • The overall reaction can be written as sodium chloride, which is water-soluble, plus silver nitrate, which is also water-soluble, reacts to form sodium nitrate, which is water-soluble, plus silver chloride, which is a solid. (mometrix.com)
  • In a combustion reaction, a fuel is heated and it reacts with oxygen . (moviecultists.com)
  • If a sodium chloride is melted at (above 801 Celsius ) ,the two electrodes are inserted in it and the electric current is passed into the molten salt,then the redox reaction takes place at electrodes. (mydigitalkemistry.com)
  • Oxidation is also crucial in the context of corrosion prevention. (pediaa.com)
  • Understanding reduction is crucial for corrosion protection. (pediaa.com)
  • By providing a cathodic protection source (e.g., sacrificial anodes), a reduction reaction can be favored at the protected metal surface, preventing it from undergoing oxidation and corrosion. (pediaa.com)
  • In thermo-chemical reduction, porous microparticles of iron oxides are reduced with green hydrogen to porous microparticles of pure iron. (tu-darmstadt.de)
  • A generally accepted, classical scheme for this reaction, in which hydrogen peroxide is a stable reaction intermediate species, can be depicted by Scheme 1 [1] . (beilstein-journals.org)
  • Polyphenols found in the enzyme preparation were found to interfere with the reduction of the dinitrosalicylic acid reagent. (who.int)
  • It is a complex 4-electron reaction that involves the breaking of a double bond and the formation of 4 OH-bonds through several elementary steps and intermediate species. (beilstein-journals.org)
  • It has also been shown that the reaction involves protonation of the O2 moiety before bond cleavage. (lu.se)
  • For a better result write the reaction in ionic form. (periodni.com)
  • Under REACH (ECHA 2008, Chapter R.7B - Endpoint Specific Guidance), the term 'Hydrolysis' refers to the "Decomposition or degradation of a chemical by reaction with water", and this is a function of pH (i.e. abiotic degradation) for the respective metal kations present in the submission item. (europa.eu)
  • Combustion is an oxidation process . (moviecultists.com)
  • The thermo-chemical oxidation of the iron particles with atmospheric oxygen to iron oxide particles represents the complementary process and closes the cycle. (tu-darmstadt.de)
  • Nowadays, the oxygen reduction reaction (ORR) is arguably one of the most important challenges in electrocatalysis and it is undoubtedly the most important cathodic process in fuel cells. (beilstein-journals.org)
  • First, the currently available experimental techniques are not capable of detecting all possible reaction intermediates in a complex process such as the ORR. (beilstein-journals.org)
  • This process gives off large quantities of heat beyond that required to initiate the reaction. (britannica.com)
  • Separate the process into half reactions. (periodni.com)
  • In the bleaching process, the bleaching agents act by releasing the oxygen into the dental structures in a reaction so-called oxidation-reduction. (bvsalud.org)
  • This process represents a reaction pathway from the peroxy intermediate after it accepts one electron from the nearby type-1 Cu site to the experimentally-observed native intermediate, which is the only fully oxidised catalytically relevant state in MCOs. (lu.se)
  • Jiang, Y. & Weiss, E. A. Colloidal quantum dots as photocatalysts for triplet excited state reactions of organic molecules. (nature.com)
  • What is the oxidation number of iron in iron (II) oxide? (helpteaching.com)
  • Oxidation originally implied a reaction with oxygen to form an oxide. (wikipedia.org)
  • The word reduction originally referred to the loss in weight upon heating a metallic ore such as a metal oxide to extract the metal. (wikipedia.org)
  • However, despite the intensive experimental and theoretical ORR research for decades, which ranges from studies on idealized model electrodes up to reaction studies in technical systems, up to now the exact ORR mechanism is not clearly known. (beilstein-journals.org)
  • Therefore, progress in the understanding of this important reaction on a molecular level, and the choice of the right approach for the design of the electrocatalysts for fuel-cell cathodes is only possible through a cooperative approach between theory and experiments. (beilstein-journals.org)
  • The key step in the reaction mechanism of multicopper oxidases (MCOs)--the cleavage of the O-O bond in O2--has been investigated using combined quantum mechanical and molecular mechanical (QM/MM) methods. (lu.se)
  • Oxidation and reduction typically occur together in a redox (reduction-oxidation) reaction. (pediaa.com)
  • For reactions in an acidic solution, balance the charge so that both sides have the same total charge by adding a H + ion to the side deficient in positive charge. (periodni.com)
  • Incorporation of the non-acidic thiol, mercaptoethanol into the reaction mixture, caused significant activation of the invertase. (who.int)
  • Lead interferes with the synthesis of heme, resulting in accumulation of ALA in tissues and elevated excretion of ALA in urine, elevation of zinc protoporphyrin in erythrocyte, reductions in blood hemoglobin, and in a hypochromic, normocytic anemia at higher levels of exposure. (cdc.gov)
  • These tables, by convention, contain the half-cell potentials for reduction. (periodni.com)
  • Phenomena occurring in the single particle are film diffusion, pore diffusion, heat transfer and heterogeneous surface reaction. (tu-darmstadt.de)
  • Any precipitate would in turn undergo further oxidation to form the highly insoluble ferric hydroxide (Fe(OH)3) as this species autocatylzes the oxidation of Fe(II). (europa.eu)
  • The necessity to build precise and realistic reaction models, which are deducted from reliable experimental results that need to be carefully taken under strict working conditions is shown. (beilstein-journals.org)