X-ray diffractionX-ray diffraction is a generic term for phenomena associated with changes in the direction of X-ray beams due to interactions with the electrons around atoms. It occurs due to elastic scattering, when there is no change in the energy of the waves. The resulting map of the directions of the X-rays far from the sample is called a diffraction pattern.
Crystallographic disorderIn X-ray crystallography, crystallographic disorder describes the existence of variable geometries within a crystal. In some cases, disorder can be described as cocrystallization. Inorganic casesDisorder is pervasive in inorganic solids. Here are a few cases: At temperatures above 360 K, NaSH adopts the NaCl structure, which implies that the HS behaves as a spherical anion owing to its rapid rotation, leading to equal occupancy of eight equivalent positions.
ProteinBiomolecule consisting of chains of amino acid residuesA representation of the 3D structure of the protein myoglobin showing turquoise α-helices. This protein was the first to have its structure solved by X-ray crystallography. Toward the right-center among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen molecule (red).Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acidresidues.
X-rayAn X-ray is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ranging from 10 nanometers to 10 picometers, corresponding to frequencies in the range of 30 petahertz to 30 exahertz (3×10 Hz to 3×10 Hz) and photon energies in the range of 100 eV to 100 keV, respectively.
CrystallographyCrystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word crystallography is derived from the Ancient Greek word κρύσταλλος (krústallos; "clear ice, rock-crystal"), and γράφειν (gráphein; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming 2014 the International Year of Crystallography.
CrystalA crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography.
Chemical bondA chemical bond is the association of atoms or ions to form molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions, as in ionic bonds; the sharing of electrons, as in covalent bonds; or some combination of these effects.
DiffractionDiffraction is the deviation of waves from straight-line propagation due to an obstacle or through an aperture, without any change in their energy. Diffraction is the same physical effect as interference, but interference is typically used for the superposition of a few waves, while the term diffraction is used when many waves are superposed.
ElectronThe electron (e, or β in nuclear reactions) is a subatomic particle whose electric charge is negative one elementary charge. It is an elementary particle contained in the matter that makes up the universe. All atoms are composed of electrons, as well as varying numbers protons and neutrons, but the electrons have almost 2,000 times less mass than the other two constituents.
DensityDensity (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D (or d) can also be used: ρ=mV,{\displaystyle ho ={\frac {m}{V}},} where ρ is the density, m is the mass, and V is the volume.
AlloyAn alloy is a mixture of chemical elements of which in most cases at least one is a metallic element, although the word is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have properties that differ from those of the pure elements from which they are made.
VitaminVitamins are organic molecules (or a set of closely related molecules called vitamers) that are essential to an organism in small quantities for proper metabolic function. These essential nutrients cannot be synthesized in the organism in sufficient quantities for survival, and therefore must be obtained through consumption. For example, vitamin C can be synthesized by some species but not by others; it is not considered a vitamin in the first instance but is in the second.
AtomSmallest unit of a chemical elementAtoms are the basic particles of the chemical elements and the fundamental building blocks of matter. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper.*As an Amazon Associate I earn from qualifying purchases.