Crystal Structures

• Crystalline - is a solid material whose constituents are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.
• Crystallographic axes - the lines drawn parallel to the lines of intersection of any three faces of the unit cell which do not lie in the same plane
• Density - mass per unit volume
• Face-centered cubic - has lattice points at the eight corners of the unit cell plus additional points at the centers of each face of the unit cell.
• Hexagonal close-packed - layers of spheres are packed so that spheres in alternating layers overlie one another. As in cubic close packing, each sphere is surrounded by 12 other spheres.
• Melting point - temperature at which a substance changes from solid to liquid state.
• Lattice energy - the strength of attraction between positive and negative ions in ionic compounds.
• Ionic bonding - occurs when an atom loses or gains electrons to form ions with opposite charges. The oppositely charged ions attract each other strongly due to electrostatic forces.
• A unit cell is the smallest repeating unit that makes up a crystal lattice
• Crystals are formed when there is an excess of solute over solvent
• Lattice parameters - collective term for primitives and interfacial angles
• Primitives - the dimensions of a unit cell
• Simple cubic - is the simplest repeating unit in a simple cubic structure. Each corner of the unit cell is defined by a lattice point at which an atom, ion, or molecule can be found in the crystal.
• Space lattice - defined as an infinite array of points in three dimensions in which every point has surroundings identical to that of every other point in the array.
• Unit cell - the smallest group of atoms of a substance that has the overall symmetry of a crystal of that substance, and from which the entire lattice can be built up by repetition in three dimensions.
• Void space - vacant space left or unutilized space in unit cell , and more commonly known as interstitial space
• crystal structure - the ordered arrangement of atoms, ions or molecules in a crystalline material.
• Crystallization - process whereby a liquid changes into a solid state with a definite shape and size.
• Unit cell - The smallest group of particles in the material that constitutes the repeating pattern
• Crystalline - particles are orderly arranged (long range order).
• Amorphous - particles are randomly oriented.
• Bonding - the process by which atoms join together to form molecules or crystals