Pearson elements

Many elements were found to experience the photoelectric effect. Germanium, copper, selenium, and cuprous oxide comprised many of the early experimental cells. In 1953 Bell Laboratories scientists Calvin Fuller and Gerald Pearson were conducting... 

This submarine vs. subaerial hypothesis for the origin of the two types of deposits (Kuroko deposits, epithermal vein-type deposits) can reasonably explain the difference in metals enriched into the deposits by HSAB (hard-soft acids and bases) principle proposed by Pearson (1963) (Shikazono and Shimizu, 1992). Relatively hard elements (base metal elements such as Cu, Pb, Zn, Mn, Fe) are extracted by chloride-rich fluids of seawater origin, while soft elements (Au, Ag, Hg, Tl, etc.) are not. Hard elements tend to form chloro complexes in the chloride-rich fluid, while soft elements form the complexes in H2S-rich and chloride-poor fluids. Cl in ore fluids is thought to have been derived from seawater trapped in the submarine volcanic and sedimentary rocks. 

Fogler, H. S. Elements of Chemical Reactor Design (Pearson Educational, 1998). 

Marshall, James Discovery of the Elements. Pearson Custom Publishing (1998)... 

Equation 16.12 expresses a relation between q and B.This is not a universal relation, but it does apply to the sp-bonded elements of the first four columns of the Periodic Table. Using chemical hardness values given by Parr and Yang (1989), and atomic volumes from Kittel (1996), it has been shown that the bulk moduli of the Group I, II, III, and IV elements are proportional to the chemical hardness density (CH/atomic volume) (Gilman, 1997). The correlation lines pass nearly through the coordinate origins with correlation coefficients, r = 0.999. Thus physical hardness is proportional to chemical hardness (Pearson, 2004). 

It is shown that the stabilities of solids can be related to Parr s physical hardness parameter for solids, and that this is proportional to Pearson s chemical hardness parameter for molecules. For sp-bonded metals, the bulk moduli correlate with the chemical hardness density (CffD), and for covalently bonded crystals, the octahedral shear moduli correlate with CHD. By analogy with molecules, the chemical hardness is related to the gap in the spectrum of bonding energies. This is verified for the Group IV elements and the isoelec-tronic III-V compounds. Since polarization requires excitation of the valence electrons, polarizability is related to band-gaps, and thence to chemical hardness and elastic moduli. Another measure of stability is indentation hardness, and it is shown that this correlates linearly with reciprocal polarizability. Finally, it is shown that theoretical values of critical transformation pressures correlate linearly with indentation hardness numbers, so the latter are a good measure of phase stability. 

The human element is not one third of sustainability it is central to its implementation (Pearson 2003). The challenge of sustainability is neither wholly technical nor rational. It is one of the change in attitude and behavior. Sustainability therefore must include the social discourse where the fundamental issues are explored collaboratively within the groups or community concerned. We do not do that very well, partly because of increasing populations, complexity, distractions, and mobility, but more because of certain characteristics of the dominant paradigm that are seen as desirable (Flicker 2001). 

Brady NC, Weil RR. Elements of the Nature and Properties of Soils, 13th ed. Upper Saddle River, NJ Pearson Prentice-Hall 2002, p. 125. 

Norman, M. D., Pearson, N. J., Sharma, A., and Griffin, W. L. (1996). Quantitative analysis of trace elements in geological materials by laser ablation ICPMS instrumental operating conditions and calibration values of NIST glasses. Geostandards Newsletter 20 247-261. 

We underline these results and the implied concepts quoting from a comprehensive review on this subject (Simon 1983). We remember indeed that, ever since it was experimentally possible to determine atomic distances in molecules and crystals, efforts have been made to draw conclusions about the nature of the chemical bonding, and to compare interatomic distances (dimensions) in the compounds with those in the chemical elements. Distances between atoms in an element can be measured with high precision. As such, however, they cannot be simply used in predicting interatomic distances in the compounds. In a rational procedure, reference values (atomic radii) have to be extracted from the individual (interatomic distances) measured values. Various functions have been suggested for this purpose. In the specific case of the metals it has been pointed out that interatomic distances depend primarily on the number of ligands and on the number of valence electrons of the atoms (Pearson 1972). 

According to Pearson (1972) the rhombohedral structure of these elements can be considered a distortion of a simple cubic structure in which the d2/d ratio would be 1. The decrease of the ratio on passing from As to Bi, and the corresponding relative increase of the strength of the X-X interlayer bond (passing from a coordination nearly 3, as for the 8 — eat rule, to a coordination closer to 6) can be related to an increasing metallic character. 

Crystal Field Theory (CFT) has also been used considerably to rationalize visible absorption spectra, hydration energies, stabilities of complexes, rates and mechanism of reaction, and redox potentials of transition element ions. These applications of CFT are summarized in a book by Basolo and Pearson 1B6). 

The remaining exceptions concern the lanthanide series, where samarium at room temperature has a particular hexagonal structure and especially the lower actinides uranium, neptunium, and plutonium. Here the departure from simple symmetry is particularly pronounced. Comparing these three elements with other metals having partly filled inner shells (transition elements and lanthanides), U, Pu, Np have the lowest symmetry at room temperature, normal pressure. This particular crystallographic character is the reason why Pearson did not succeed to fit the alpha forms of U, Pu, and Np, as well as gamma-Pu into his comprehensive classification of metallic structures and treated them as idiosyncratic structures . Recent theoretical considerations reveal that the appearance of low symmetries in the actinide series is intimately linked to the behaviour of the 5f electrons. 

An altogether different way of looking at your management development in the context of your life and career is provided by a unique book by Carol Pearson entitled The Hero Within (1989). Subtitled Six Archetypes We Live By, the book describes characters we may Inhabit as we move through life. Within each archetype Pearson sees a heroic element, which we need to discover and bring out in ourselves. 

Table 1.1 gives the structures of the elements at zero temperature and pressure. Each structure type is characterized by its common name (when assigned), its Pearson symbol (relating to the Bravais lattice and number of atoms in the cell), and its Jensen symbol (specifying the local coordination polyhedron about each non-equiyalent site). We will discuss the Pearson and Jensen symbols later in the following two sections. We should note,... 

Element Common name Pearson symbol fersen symbol... 

Pearson, following up on an idea of Chatt, Ahrland, and Davies, divided the chemical elements into groups according to the acid-base (electron pair acceptor-donor) properties of their atoms or common ions ... 

Relative sizes of ions and the degree of covalence are important in determining structures of MX compounds. Mooser and Pearson plotted the average principal quantum number of the ions vs. the difference in electronegativites of the elements to give reasonable separation of CsCl, NaCl, ZnS (hep), and ZnS (ccp) structures. (E. Mooser and W.B. Pearson, Acta Crystallogy 1959 12 1015.) This plot is more successful than the radius ratio plots. 

Using finite element stress analysis, Huang et al. (1993b) demonstrated that shear bands must appear at 45°, between voids formed in a previous step. As there are many particles, a network of shear bands is generated in the deformed sample (Yee and Pearson, 1986). Their growth generates the appearance of the first crack. 

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