Intramolecular forces ionic bonds

You have learned that pure covalent compounds are not held together by ionic bonds in lattice structures. They do form liquids and solids at low temperatures, however. Something must hold the molecules together when a covalent compound is in its liquid or solid state. The forces that bond the atoms to each other within a molecule are called intramolecular forces. Covalent bonds are intramolecular forces. In comparison, the forces that bond molecules to each other are called intermolecular forces. 

The strengths of intermoiecuiar forces in different substances vary over a wide range but are generally much weaker than intramolecular forces—ionic, metallic or covalent bonds ( FIGURE 11.3). Less energy, therefore, is required to vaporize a liquid or melt a solid than to break covalent bonds. For example, only 16 kj/mol is required to overcome the intermoiecuiar attractions in liquid HCl in order to vaporize it. In contrast, the energy required to break the covalent bond in HCl is 431 kj/mol. Thus, when a molecular substance such as HCl changes from solid to liquid to gas, the molecules remain intact. 

The chemical structure of a typical divalent metal acetylacetonate, for which the abbreviation would be MCacac). These compounds are internally bonded ionically and complexed to oxygen at the same time. Thus, their intramolecular forces are very strong (they are stable), but their interraolecular forces are weak (they are volatile). 

A number of different molecular mechanisms can underpin the loss of biological activity of any protein. These include both covalent and non-covalent modification of the protein molecule, as summarized in Table 6.5. Protein denaturation, for example, entails a partial or complete alteration of the protein s three-dimensional shape. This is underlined by the disruption of the intramolecular forces that stabilize a protein s native conformation, namely hydrogen bonding, ionic attractions and hydrophobic interactions (Chapter 2). Covalent modifications of protein structure that can adversely affect its biological activity are summarized below. 

Ionic Bond intramolecular force created when electrons are transferred from one atom to another creating ions that possess electrostatic attraction for one another Ionic Solid a solid composed of anions and cations such as NaCl... 

Recall that atoms can form stable units called molecules by sharing electrons. This is called intramolecular (within the molecule) bonding. In this chapter we will consider the properties of the condensed states of matter (liquids and solids) and the forces that cause the aggregation of the components of a substance to form a liquid or a solid. These forces may involve covalent or ionic bonding, or they may involve weaker interactions usually called intermolecular forces (because they occur between, rather than within, molecules). 

If all particles of matter at room temperature have the same average kinetic energy, why are some materials gases while others are liquids or solids The answer lies with the attractive forces within and between particles. The attractive forces that hold particles together in ionic, covalent, and metallic bonds are called intramolecular forces. The prefix intra- means within. For example, intramural sports are competitions among teams from within a single school. The term molecular can refer to atoms, ions, or molecules. Table 13-2 summarizes what you learned about intramolecular forces in Chapters 8 and 9. 

The intramolecular forces that hold together ionic, covalent, and metallic bonds are stronger than inter-molecular forces. 

There are five types of interactions within and between molecules. Intramolecular interactions include covalent and ionic bonds. Intermolecular interactions include van der Waals s forces, dipole-dipole, and hydrogen bonds. Table 1 lists the typical energies for these interactions. 

Elevated pressures can induce functional and structural alterations of proteins. The effects of pressure are governed by Le Chatelier s principle. According to this principle, an increase in pressure favours processes which reduce the overall volume of the system, and conversely increases in pressure inhibit processes which increase the volume. The effects of pressure on proteins depend on the relative contribution of the intramolecular forces which determine their stability and functions. Ionic interactions and hydrophobic interactions are disrupted by pressure. On the other hand, stacking interactions between aromatic rings and charge-transfer interactions are reinforced by pressure. Hydrogen bonds are almost insensitive to pressure. Thus, pressure acts on the secondary, tertiary, and quaternary structure of proteins. The extent and the reversibility, or irreversibility, of pressure effects depend on the pressure range, the rate of compression, and the duration of exposure to increased pressures. These effects are also influenced by other environmental parameters, such as the temperature, the pH, the solvent, and the composition of the medium. 

Initially it is a good idea to introduce the different types of bonds that hold atoms together in molecules (intramolecular forces), metal lattices and ionic lattices. After that we are going to look at which types of forces that interacts between molecules (intermolecular forces). 

When atoms and molecules approach one another closely, they begin to exert forces on one another that do not result from the sharing or transfer of electrons. These forces are known as intermolecular forces if the forces are between two neighboring molecules and are called intramolecular forces if they are between different parts of the same molecule. These forces are much weaker than covalent or ionic bonds but are very important to the properties of polymers because the huge size of polymer molecules results in a proportionally huge number of these attractions. 

Intramolecular forces occur within a molecule and include ionic and covalent bonds. 

Fig. 217. Possible mode of intramolecular, cation selective bridge in the kappa carrageenan molecule in aqueous solution at low" temperature ( ) ionic bonding and (------) electrostatic force...

---