Ionic solid melting

When an ionic solid melts into a liquid, the liquid contains many free-floating cations and anions. These charged particles give the liquid a unique property the ability to conduct electricity. The cations and anions can move around to carry an electrical charge through the liquid. These liquids are known as good conductors. 

The situation changes dramatically, however, when an ionic solid melts to become a liquid or is dissolved in solution. The ions—previously locked in position—are now free to move and conduct an electric current. Both ionic compounds in solution and in the liquid state are excellent conductors of electricity. An ionic compound whose aqueous solution conducts an electric current is called an electrolyte. You will learn more about solutions of electrolytes in Chapter 14. 

PCI5 is even closer to the ionic-covalent borderline than is PF5, the ionic solid [PCl4]" [PCl6] melting (or subliming) to give a covalent molecular... 

The overall lattice energies of ionic solids, as treated by the Born-Eande or Kaputin-sldi equations, thus depends on (i) the product of the net ion charges, (ii) ion-ion separation, and (iii) pacldng efficiency of the ions (reflected in the Madelung constant, M, in the Coulombic energy term). Thus, low-melting salts should be most... 

Ionic solids do not conduct electricity because the charged ions are fixed in position. They become good conductors, however, when melted or dissolved in water. In both cases, in the melt or solution, the ions (such as Na+ and Cl-) are free to move through the liquid and thus can conduct an electric current. 

When an ionic solid like sodium chloride is melted, the molten salt conducts electric current. The conductivity is like that of an aqueous salt solution Na+ and Cl- ions are present. The extremely high melting temperature (808°C) shows that a large amount of energy is needed to tfear apart the regular NaCl crystalline arrangement to free the ions so they can move. 

Ionic solids, such as lithium fluoride and sodium chloride, form regularly shaped crystals with well defined crystal faces. Pure samples of these solids are usually transparent and colorless but color may be caused by quite small impurity contents or crystal defects. Most ionic crystals have high melting points. 

The strong attraction between oppositely charged ions accounts for the typical properties of ionic solids, such as their high melting points and their brittleness. A high temperature is required before the ions are able to move past one... 

Ionic solids typically have high melting points and are brittle. The coulombic interaction between ions in a solid is large when the ions are small and highly charged. 

Explain why ionic solids such as NaCl have high melting points yet dissolve readily in water, whereas network solids such as diamond have very high melting points and do not dissolve in solvents. 

These forces affect the boiling point, melting point, hardness, and electrical and heat conductivity of a substance. In this chapter, we will study metals, ionic solids, network solids, dipole-dipole attractions, van der Waals forces and hydrogen bonds. 

As the attraction between the ions is strong, the melting and boiling points of ionic solids are very high. For example, NaCl melts at 801°C. 

Ionic solids have their lattices composed of ions held together by the attraction of opposite charges of the ions. These crystalline solids tend to be strong with high melting points due to the strength of the intermolecular forces. NaCl and other salts are example of ionic solids. 

The melting point of NaCl is 801°C, of CaCl2 is 782°C, and of AICI3 is 190°C. The electrostatic forces of attraction between ions increase with an increase in the charge. In these ionic solids, the charge on the cations Na", Ca ", and Al ... 

Which ionic solid would you expect to have a higher melting point Lil or LiBr Justify your answer. 

The disordered nature of the a-AgI structure may be regarded as intermediate between that of a typical ionic solid in which every lattice site is occupied and a typical ionic liquid in which both anions and cations are disordered. This is borne out by entropy calculations based on heat capacity data (O Keeffe and Hyde, 1976). These show a large increase in entropy at the P (or y) to a transition and a similar increase in entropy on melting of the a polymorph at 557 °C ... 

The oxidizers used in high-energy mixtures are generally ionic solids, and the "looseness" of the ionic lattice is quite important in determining their reactivity [3]. A crystalline lattice has some vibrational motion at normal room temperature, and the amplitude of this vibration increases as the temperature of the solid is raised. At the melting point, the forces holding the crystalline solid to-... 

When ionic compounds are melted or dissolved so that the individual ions can move about, the resulting liquid is a very good conductor of electricity. Ionic solids, however, are often poor conductors of electricity. 

Molecular solids are typically less bard than ionic solids and melt at lower temperatures. 

A glass is an ionic solid with an amorphous structure resembling that of a liquid. Glass has a network structure based on a nonmetal oxide, usually silica, Si02, that has been melted together with metal oxides that act as network modifiers. ... 

In earlier chapters, we saw examples of how the metallic or nonmetallic character of an element affects its chemistry. Metals tend to form ionic compounds with nonmetals, whereas nonmetals tend to form covalent, molecular compounds with one another. Thus, binary metallic hydrides, such as NaH and CaH2, are ionic solids with high melting points, and binary nonmetallic hydrides, such as CH4, NH3, H20, and HF, are covalent, molecular compounds that exist at room temperature as gases or volatile liquids (Section 14.5). 

Oxides exhibit similar trends. In the third row, for example, Na20 and MgO are typical high-melting, ionic solids, and P4O10, S03, and C1207 are volatile, covalent, molecular compounds (Section 14.9). The metallic or nonmetallic character of an oxide also affects its acid-base properties. Na20 and MgO are basic, for example,... 

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