Important Terms

This section explains the special terms used in the handbook, gives the sources of specific items, and includes other information that will be useful to the reader in interpreting the data. 

The expression Not Pertinent means that the data item either has no real meaning (such as the flash point of a inflammable chemical) or is not required for assessing a hazardous situation. The expression Data Not Available means that the information sought was not found in the general data sources consulted during the preparation of this handbook. In a few cases where important data were not available, values were estimated by usually reliable procedures all such values are labeled (est.) . If more accurate values for those items are found, they will be included in later revisions. 

The name used for each of the chemicals included is either (1) that specified in the Code of Federal Regulations (CFR), Titles 46 and 49 or (2) a common name for those chemicals known to be hazardous during shipment. In this regard, for most chemical names, the shipping name recommended by the USDOT is used as it appears in Title 49 of the CFRs. The data are arranged in alphabetical order by chemical name. 

Ligands that can bond to a metal through only one donor atom at a time are mono-dentate (Latin dent, tooth ). Ligands that have more than one donor linked by other atoms (often carbons) so that the donors can coordinate to the same metal are called 

Unless othemise noted, all content on this page is O Cengage Learning. 

The coordination number of a metal atom or ion in a complex is the number of donor atoms to which it is bonded, which is not necessarily the number of ligands. The coordination sphere includes the metal or metal ion (called the central atom) and its ligands, but no uncoordinated counterions. For example, the coordination sphere of hexaamminecobalt(ni) chloride, [Co(NH3)6]Cl3, is the hexaamminecobalt(III) ion, [Co(NH3)6]. The chloride counterions are not bonded to the Co center and, in this case, are not acting as ligands. These terms are illustrated in Table 25-5. 

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A glossary of important terms may be found immediately before the index at the back of the book... 

Analytical chemists converse using terminology that conveys specific meaning to other analytical chemists. To discuss and learn analytical chemistry you must first understand its language. You are probably already familiar with some analytical terms, such as "accuracy and "precision, but you may not have placed them in their appropriate analytical context. Other terms, such as "analyte and "matrix, may be less familiar. This chapter introduces many important terms routinely used by analytical chemists. Becoming comfortable with these terms will make the material in the chapters that follow easier to read and understand. 

An overview of important terms and definitions useful in assessing the potentially harmful effects of air pollutants, and... 

There are a number of important terms that should be committed to memory. These... 

At the end of this chapter you will find four annexes. The first is a list of important terms and their definitions. These terms will help to orient you to discussions in later chapters. Next you will find a Nomenclature section that defines all the... 

Following are some of the important terms used in the field of polymer blends and alloys [54]. 

The coke yield of a given cat cracker is essentially constant. The FCC produces enough coke to satisfy the heat balance. However, a more important term is delta coke. Delta coke is the difference between the coke on the spent catalyst and the coke on the regenerated catalyst. At a given reactor temperature and constant CO2/CO ratio, delta coke controls the regenerator temperature. 

Where R is the gas constant, T the temperature (K), Fthe Faraday constant and H2 is the relative partial pressure (strictly, the fugacity) of hydrogen in solution, which for continued evolution becomes the total external pressure against which hydrogen bubbles must prevail to escape (usually 1 atm). The activity of water a jo is not usually taken into account in elementary treatments, since it is assumed that <7h2 0 = U nd for dilute solutions this causes little error. In some concentrated plating baths Oh2 0 I O nd neither is it in baths which use mixtures of water and miscible organic liquids (e.g. dimethyl formamide). However, by far the most important term is the hydrogen ion activity this may be separated so that equation 12.1 becomes... 

The more important terms used in relation to humidification are defined as follows ... 

In the case of crystals containing highly charged cations the most important terms in the expression for the crystal energy are those representing... 

The interactions between electrons are inherently many-body forces. There are several methods in common use today which try to incorporate some, or all, of the many-body quantum mechanical effects. An important term is that of electronic exchange [57, 58]. Mathematically, when two particles in the many-body wavefunction are exchanged the wavefunction changes sign ... 

Whenever one compound uses its electrons to attack another compound, we call the attacker a nucleophile, and we call the compound being attacked an electrophile. It is very simple to tell the difference between an electrophile and a nucleophile. You just look at the arrows and see which compound is attacking the other. A nucleophile will always use a region of high electron density (either a lone pair or a bond) to attack the electrophile (which, by definition, has a region of low electron density that can be attacked). These are important terms, so let s make sure we know how to identify nucleophiles and electrophiles. 

As we leam addition reactions, we will be using two important terms to describe the regiochemistry Markovnikov and anti-Markovnikov. To use these terms properly, we must be able to recognize which carbon is more snbstituted. Consider the following example ... 

The specific application of the first law of thermodynamics to study chemical reactions is referred to as thermochemistry. Thermochemistry is concerned with the measurement or calculation of the heat absorbed or given out in chemical reactions. Precisely therefore, thermochemistry is the part of thermodynamics dealing with enthalpy (i.e., heat content) changes accompanying chemical reactions. In this context, it will be useful to refer to some of the important terms associated with thermal effects. 

Mahdihassan, S. Alchemy its three important terms and their significance. MedJ Australia 48, no. 2 (5 Aug 1961) 227-228. 

Two important terms used to describe additives in polymeric mixtures are distribution and "dispersion . When mixing polymers with additives, we want to create a system in which the additive is both well distributed and dispersed. Distribution refers to the even placement of the additive throughout the polymer. For example, a well made batch of chocolate chip cookies has good distribution of the chips if every bite has a chocolate chip in it. A poorly distributed cookie would have all its chips on one side. Dispersion, on the other hand, refers to the separation of the individual components of a solid additive into its smallest parts. Figure 10.6 illustrates both good and bad distribution and dispersion. 

Now the bubble collapse is discussed using the Rayleigh-Plesset equation. After the bubble expansion, a bubble collapses. During the bubble collapse, important terms in the Rayleigh-Plesset equation are the two terms in the left hand side of (1.13). Then, the bubble wall acceleration is expressed as follows. 

Note - This glossary is by no means exhaustive but it hopefully contains most of the more important terms you will come across in a typical NMR environment. Some of the entries may not even have featured in the text itself. Whilst every effort has been made to make the entries scientifically valid, please note that it is sometimes difficult to condense a highly complex topic into a pithy three-line explanation, so some of the definitions are sketchy to say the least ... 

Average or effective Hamiltonian theory, as introduced to NMR spectroscopy by Waugh and coworkers [55] in the late 1960s, has in all respects been the most important design tool for development of dipolar recoupling experiments (and many other important experiments). In a very simple and transparent manner, this method facilitates delineation of the impact of advanced rf irradiation schemes on the internal nuclear spin Hamiltonians. This impact is evaluated in an ordered fashion, enabling direct focus on the most important terms and, in the refinement process, the less dominant albeit still important terms in a prioritized manner. 

Validation studies a glossary of some important terms... 

Hydrophobicity (log P) is related to the desolvation of the ligand, and it is assumed that the desolvation of the ligands going from water to octanol parallels that of going from water to a cleft or pocket of a receptor. Thus, log P may be an important term in establishing quantitative relationships between structure and activity (26). In order to examine the influence of the lipohilic character of the 4-PIOL analogs on the affinity for the GABAa receptor, QSAR analysis was performed (24). 

The correct understanding of these words and their implications is of fundamental importance for the scientific and industrial community interested in sensor science development, since it allows the correct dissemination of both experimental and theoretic results, even if other important terms in the sensor field have not been discussed in this chapter, such as speed of response, reversibility, repeatability, reproducibility, and stability, to which some attention was paid during the presentation of this work at the ASI. 

Clearly, the term E2 will dominate, but if we assume that this does not vary significantly from metal to metal (see above), then the important term will be Et. Experimentally, it is observed that it is those carbonyl clusters that exhibit low values of Ei which more readily un-... 

The next term in Equation (5) is the halide affinity of the metal halide, Ax (MtXJ. This is a very important term for the final value of AH4e and a term which, were it generally available, would facilitate worthwhile conclusions as to which metal halide would be the best anionogen. However, only two halide affinities for the metals of interest are known to us, viz. the fluoride affinities of BF3 and WF5 [26, 27]. In Scheme 3 the role of the halide affinity in the Born-Haber cycle for the BIE [Equation (iv)] is emphasised and an alternative route for the same energy contribution to AH4B is given. The individual BDE D(XBMt-X) is, like the halide affinity, known only for a very few examples of interest,... 

It is observed in table 7.2 that the most important terms in the reduction to standard states are the decomposition of aqueous nitric acid (AU (,), the compression of the initial gaseous phase (02+H20) from a negligibly small pressure to the initial pressure (A 6/7), the decompression of the final gaseous phase (02 + N2 + C02 + H20) from the final pressure to a negligibly small pressure (Af/19), and the evaporation of C02 from the final aqueous phase (AU o). The terms relative to the vaporization and condensation of liquid water (A f/3 — AIJ24) almost cancel out. 

It has been well known for some time (e.g. [36]) that the next component in importance is that of connected triple excitations. By far the most cost-effective way of estimating them has been the quasiper-turbative approach known as CCSD(T) introduced by Raghavachari et al. [37], in which the fourth-order and fifth-order perturbation theory expressions for the most important terms are used with the converged CCSD amplitudes for the first-order wavefunction. This account for substantial fractions of the higher-order contributions a very recent detailed analysis by Cremer and He [38] suggests that 87, 80, and 72 %, respectively, of the sixth-, seventh-, and eighth-order terms appearing in the much more expensive CCSDT-la method are included implicitly in CCSD(T). 

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