crystalline

(noun)

Having a regular three-dimensional molecular lattice structure.

Related Terms

Examples of crystalline in the following topics:

  • Crystal Structure: Packing Spheres

    • Consider the arrangement of spheres within a lattice to form a view of the structure and complexity of crystalline materials.
    • The unique arrangement of atoms or molecules within a crystalline solid is referred to as the crystal structure of that material.
    • A crystal structure reflects the periodic pattern of the atoms which compose a crystalline substance.
    • The structure seen within the crystalline lattice of a material can be described in a number of ways.
    • Within a crystalline material, each atom can be thought of as a sphere.

  • Crystal Structure: Closest Packing

    • Closest packing refers to the most efficient way to arrange atoms in a crystalline unit cells.
    • A crystalline material's structure is typically visualized as being composed of unit cells.
    • This section considers how the packing of atoms within unit cells contributes to a crystalline solid's lattice structure.
    • The three dimensional structure of a solid crystalline material is established through the periodic patterning of the atoms that make up the crystal.
    • The arrangement of the atoms in a crystalline solid affects atomic coordination numbers, interatomic distances, and the types and strengths of bonding that occur within the solid.

  • Characteristics of Condensation Polymers

    • The presence of polar functional groups on the chains often enhances chain-chain attractions, particularly if these involve hydrogen bonding, and thereby crystallinity and tensile strength.
    • The difference in Tg and Tm between the first polyester (completely aliphatic) and the two nylon polyamides (5th & 6th entries) shows the effect of intra-chain hydrogen bonding on crystallinity.
    • The replacement of flexible alkylidene links with rigid benzene rings also stiffens the polymer chain, leading to increased crystalline character, as demonstrated for polyesters (entries 1, 2 &3) and polyamides (entries 5, 6, 7 & 8).
    • This cold-drawing procedure organizes randomly oriented crystalline domains, and also aligns amorphous domains so they become more crystalline.

  • Amorphous Solids

    • Amorphous solids lack a crystalline or long-range order to their atomic structure.
    • Solids can be divided into two classes: crystalline and amorphous.
    • The first and most common type, known as crystalline or morphous, has regular crystal lattices, or long-range order.

  • Properties of Macromolecules

    • Crystallinity occurs when linear polymer chains are structurally oriented in a uniform three-dimensional matrix.
    • In the diagram below, crystalline domains are colored blue.
    • Consequently, crystallinity is high and the cellulose molecules do not move or slip relative to each other.
    • Tm is the temperature at which crystalline domains lose their structure, or melt.
    • As crystallinity increases, so does Tm.

  • Properties of Quartz and Glass

    • Glass is a non-crystalline solid material made of silica, while quartz is a crystalline silicate mineral with piezoelectric properties.
    • Glass is an amorphous (non-crystalline) solid material.

  • Diffraction Revisited

    • Clinton Joseph Davisson and Lester Halbert Germerguided their beam through a crystalline grid to observe diffraction patterns.
    • The periodic structure of a crystalline solid acts as a diffraction grating, scattering the electrons in a predictable manner.
    • Neutrons have been studied for the determination of crystalline structures.

  • Anionic Chain-Growth Polymerization

    • Many of the resulting polymers are largely isotactic in configuration, and have high degrees of crystallinity.

  • Ziegler-Natta Catalytic Polymerization

    • In the case of ethylene, rapid polymerization occurred at atmospheric pressure and moderate to low temperature, giving a stronger (more crystalline) product (HDPE) than that from radical polymerization (LDPE).

  • Phosphorus Compounds as Reducing Agents

    • Triphenylphosphine is also oxidized by halogens, and with bromine yields dibromotriphenylphosphorane, a crystalline salt-like compound, useful for converting alcohols to alkyl bromides.