Atomic solid

Solids whose composite units are individual atoms are atomic solids. SoUd xenon (Xe), iron (Fe), and silicon dioxide (Si02) are examples of atomic soUds. We can classify atomic solids themselves into three categories—nonbondmg atomic solids, metallic atomic solids, and network covalent atomic solids—each held together by a different kind of force. 

Network covalent atomic solids, such as diamond, graphite, and silicon dioxide, are held together by covalent bonds. The crystal structures of these solids are more restricted by the geometrical constraints of the covalent bonds (which tend to be more directional than intermolecular forces, ionic bonds, or metallic bonds) so they do not tend to form closest-packed structures. 

A FIGURE 11.58 Tlie Structure of Quartz (a) Quartz consists of an array of Si04 tetrahedra with shared oxygen atoms, (b) Glass is amorphous Si02- 

Nonbonding atomic solids, such as solid xenon, are held together by relatively weak dispersion forces. Xenon atoms have stable electron configurations and therefore do nof form covalent bonds with each other. Consequently, solid xenon, like other nonbonding atomic solids, has a very low melting point (about —112 °C). 

A FIGURE 12.29 Diamond a covalent atomic soiid In diamond, carbon atoms form covalent bonds in a three-dimensional hexagonal pattern. 

Identify each solid as molecular, ionic, or atomic. 

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One of the first attempts to calculate the thermodynamic properties of an atomic solid assumed that the solid consists of an array of spheres occupying the lattice points in the crystal. Each atom is rattling around in a hole at the lattice site. Adding energy (usually as heat) increases the motion of the atom, giving it more kinetic energy. The heat capacity, which we know is a measure of the ability of the solid to absorb this heat, varies with temperature and with the substance.8 Figure 10.11, for example, shows how the heat capacity Cy.m for the atomic solids Ag and C(diamond) vary with temperature.dd ee The heat capacity starts at a value of zero at zero Kelvin, then increases rapidly with temperature, and levels out at a value of 3R (24.94 J-K -mol-1). The... 

But at low temperatures, equation (10.148) does not quantitatively predict the shape of the CV. m against T curve. For example, Figure 10.12 compares the experimental value of CV m for diamond with that predicted from equation (10.148). It is apparent that the Einstein equation predicts that CV.m for diamond will decrease too rapidly at low temperatures. Similar results would be obtained for Ag and other atomic solids. 

Chapter 10, the last chapter in this volume, presents the principles and applications of statistical thermodynamics. This chapter, which relates the macroscopic thermodynamic variables to molecular properties, serves as a capstone to the discussion of thermodynamics presented in this volume. It is a most satisfying exercise to calculate the thermodynamic properties of relatively simple gaseous systems where the calculation is often more accurate than the experimental measurement. Useful results can also be obtained for simple atomic solids from the Debye theory. While computer calculations are rapidly approaching the level of sophistication necessary to perform computations of... 

The high-temperature contribution of vibrational modes to the molar heat capacity of a solid at constant volume is R for each mode of vibrational motion. Hence, for an atomic solid, the molar heat capacity at constant volume is approximately 3/. (a) The specific heat capacity of a certain atomic solid is 0.392 J-K 1 -g. The chloride of this element (XC12) is 52.7% chlorine by mass. Identify the element, (b) This element crystallizes in a face-centered cubic unit cell and its atomic radius is 128 pm. What is the density of this atomic solid ... 

C02-0028. Draw molecular pictures that show part of a sample of each of the following (a) mercury, an atomic liquid (b) iron, an atomic solid and (c) neon, a monatomic gas. 

In a mono-atomic solid, the EXAFS function x k) is the sum of the scattering contributions of all atoms in neighboring coordination shells ... 

Figure 4 Sketch of two possible stereochemical arrangements for a chiral monomer. P represents the polymer chain, R represents a vinyl substitutent on a carbon, H represents hydrogen, (a) Linear sketch showing one conformation and two configurations (bracketed and unbracketed). The apex of bonds is a tetrahedrally bonded carbon atom (solid and dashed circles), (b) Newman projection of the same monomer showing the free rotation about the C-C bond.

Proceedings Atoms, Solids and Plasmas in Super-Intense Laser Fields... 

Equation Approach for Atom/Solid-Surface Scattering General Formulation for Classical Scattering off Harmonic Solids. 

Atomic solids have individual atoms held in place by London forces. The noble gases are the only atomic solids known. 

Atomic solids are made up of individual atoms that are held together solely by dispersion forces. The number of naturally occurring atomic solids is quite small. In fact, the noble gases in their solid state are the only examples. Since the only forces holding atomic solids together are dispersion forces, these solids have very low melting and boiling points. 

CAM or PCAM equipment may be used for the rapid and accurate determination of atomizer solids contributions to textile workplace dust levels. Experience with low solids water provided by both reverse osmosis and deionizer equipment is described. In certain cases, these determinations may be made in less than one day and sometimes even without the use of low solids water equipment. 

Comparison of Predicted and Measured Atomizer Solids Residue Contributions... 

Alternatively stated, the losses for the atomizer solids residue particles in a complete single pass is 80%. This is reasonable because this particular air washer system had good inlet filtration media. 

Figure 20. Structural parameters as a function of time extracted by fitting the data shown in Figure 20. (A) Data collected during the oxidation of the Pt/C electrode and (B) during the reduction long dashes, first shell O coordination number (no. of O atoms) short dashes, first shell Pt coordination number (no. of Pt atoms) solid line, absorption peak intensity (effectively white line intensity).(Reproduced with permission from ref 43. Copyright 1995 Elsevier Sequoia S.A., Lausanne.)...

Fig.l Two layers of squaric acid crystal at room temperature, one is filled the other one is clear. Large circles represent oxygen, medium circles carbon and small circles hydrogen atoms. Solid heavy lines indicate covalent bonds while solid thin lines indicate hydrogen bonds. This representation refers to four unit cells [5]... 

Figure 5.5. Types of electron momentum densities no(p) >n atoms. Solid lines are used for the total density, whereas dotted lines and crosses indicate the contribution from the outermost s and p orbitals, respectively. Top left a type I density for the potassium atom. Top right a typical type II density for the argon atom. Bottom left a typical type III density for the silver atom. Bottom right a closeup of rio(p) for the silver atom showing the minimum and secondary maximum. Adapted from Thakkar [29].

Such particles can also be used as models of atomic fluids or atomic solids of interest in physics, chemistry, and materials science (see, e.g., Section 13.2, Figs. 13.3 and 13.4 see also Murray and Grier 1995). 

Figure 3 The arrangement of zirconium atoms (solid circles) and oxygen atoms (open circles) in molecules of [Zr13Og(OMe)36] 0(2) and 0(3) are bridging oxygen atoms while the other oxygen atoms are part of methoxide...

Fig. 2. Diagrammatic representation of the unit cell of cellulose, The monoclinic cell, dimensions 10.3 A x 8.35 A = S4. is delineated hy solid lines with one cellulose chain at each vertical edge and one lamiparallell in the center. Open circles = carbon atoms, solid circles - oxygen atoms. For clearness of the diagram, the hydroxyl groups on carbons 2, 3, and 6 are omitted and hydrogen atoms are omitted. TWo spacing at 6.1 A and 5.4 A are included, inasmuch as these are strongly represented in the x-ray diffraction diagram...

In deriving the Debye heat capacity equation, one assumes that the atoms in an atomic solid are vibrating with a range or frequencies v varying from u = 0 to a maximum u — vm. The resulting equation for calculating Cv, m is... 

Consider your models of three atomic solids and one ionic solid. Are atomic solids more dense or less dense than ionic solids Explain your answer. 

Atomic solids are often more dense than ionic solids. In ionic solids, ions of different sizes must be packed together. In this packing, spaces between ions make the solid less dense than atomic solids, where the atoms are uniform in size. 

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