Orthorhombic

Definition

Orthorhombic refers to one of the seven crystal systems characterized by three mutually perpendicular axes of different lengths. This system is known for its unique geometric arrangement, which influences the properties and behaviors of the crystals that fall under this category, including their symmetry and lattice structure.

5 Must Know Facts For Your Next Test

1. The orthorhombic system has three axes that are all of different lengths, denoted as a, b, and c, with each axis intersecting at right angles (90 degrees).
2. Examples of minerals that crystallize in the orthorhombic system include olivine, topaz, and sulfur.
3. The orthorhombic lattice can be further categorized into four distinct Bravais lattices: simple orthorhombic, body-centered orthorhombic, base-centered orthorhombic, and face-centered orthorhombic.
4. Symmetry operations in the orthorhombic system include rotation and reflection that maintain the crystal's overall symmetry despite variations in axis lengths.
5. Orthorhombic crystals exhibit unique physical properties such as anisotropy, meaning their optical and mechanical properties vary depending on the direction of measurement.

Review Questions

• How does the orthorhombic crystal system differ from other crystal systems in terms of its axis arrangement?
  • The orthorhombic crystal system is distinct because it has three mutually perpendicular axes (a, b, c) that are all of different lengths. This arrangement contrasts with systems like cubic, where all axes are equal in length and also intersect at right angles. The unique dimensions of the orthorhombic axes influence not only the crystal's shape but also its physical properties and symmetry operations.
• Discuss the significance of Bravais lattices within the context of the orthorhombic system and provide examples.
  • Bravais lattices are crucial for categorizing crystals based on their periodic arrangements in space. Within the orthorhombic system, there are four specific Bravais lattices: simple orthorhombic, body-centered orthorhombic, base-centered orthorhombic, and face-centered orthorhombic. Each type has unique structural characteristics that affect how atoms or molecules are organized within the crystal structure, ultimately influencing properties like stability and reactivity.
• Evaluate how understanding lattice parameters is important when studying orthorhombic crystals and their applications in fields like nucleic acid crystallography.
  • Understanding lattice parameters is vital for studying orthorhombic crystals because these parameters define the unit cell dimensions that affect how molecules interact within a crystal. In nucleic acid crystallography, knowing these dimensions helps researchers accurately determine the arrangement of DNA or RNA structures at an atomic level. This understanding can inform various applications such as drug design or genetic engineering by providing insights into molecular behavior and stability based on their crystallographic properties.

Related terms

Crystal System: A classification of crystals based on their symmetry and lattice parameters, which includes seven distinct categories such as cubic, tetragonal, and orthorhombic.

Bravais Lattice: A set of 14 unique lattice structures that describe the possible arrangements of points in space, helping to categorize crystal systems, including the orthorhombic lattice.

Lattice Parameters:

The constants that define the dimensions of the unit cell in a crystal lattice, including edge lengths and angles, which are essential for determining the structure of orthorhombic crystals.