Amorphous Vs Crystalline Full Charges Are

For example, diamond is one of the hardest substances known and melts above 3500 C.

It is also possible for a liquid to freeze before its molecules become arranged in an orderly pattern.

The resulting materials are called amorphous solids or noncrystalline solids (or, sometimes, glasses).

The particles of such solids lack an ordered internal structure and are randomly arranged (Figure 1).

Substances that consist of large molecules, or a mixture of molecules whose movements are more restricted, often form amorphous solids.

For examples, candle waxes are amorphous solids composed of large hydrocarbon molecules.

Some substances, such as boron oxide (shown in Figure 2), can form either crystalline or amorphous solids, depending on the conditions under which it is produced.

Also, amorphous solids may undergo a transition to the crystalline state under appropriate conditions.

These forces are primarily responsible for the physical properties exhibited by the bulk solids.

The following sections provide descriptions of the major types of crystalline solids: ionic, metallic, covalent network, and molecular.

Amorphous Vs Crystalline Full Charges Are

This is due to the very strong attractions between the ionsin ionic compounds, the attractions between full charges are (much) larger than those between the partial charges in polar molecular compounds.

This will be looked at in more detail in a later discussion of lattice energies.

Although they are hard, they also tend to be brittle, and they shatter rather than bend.

Ionic solids do not conduct electricity; however, they do conduct when molten or dissolved because their ions are free to move.

Many simple compounds formed by the reaction of a metallic element with a nonmetallic element are ionic.

The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.

All exhibit high thermal and electrical conductivity, metallic luster, and malleability.

Because of their malleability (the ability to deform under pressure or hammering), they do not shatter and, therefore, make useful construction materials.

Mercury is a liquid at room temperature, and the alkali metals melt below 200 C.

Several post-transition metals also have low melting points, whereas the transition metals melt at temperatures above 1000 C.

These differences reflect differences in strengths of metallic bonding among the metals.

The atoms in these solids are held together by a network of covalent bonds, as shown in Figure 5.

To break or to melt a covalent network solid, covalent bonds must be broken.

Because covalent bonds are relatively strong, covalent network solids are typically characterized by hardness, strength, and high melting points.