A crystal or crystalline solid is a solid material whose constituents 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. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification.
OpenEye Scientific Software is an American software company founded by Anthony Nicholls in 1997. It develops large-scale molecular modelling applications and toolkits. Following OpenEye's acquisition by Cadence Design Systems for $500 million in September 2022, the company was rebranded to OpenEye Cadence Molecular Sciences and operates as a business unit under Cadence.
Jerry Donohue was an American theoretical and physical chemist. He is best remembered for steering James D. Watson and Francis Crick towards the correct structure of DNA with some crucial information.
In crystallography, polymorphism describes the phenomenon where a compound or element can crystallize into more than one crystal structure. The preceding definition has evolved over many years and is still under discussion today. Discussion of the defining characteristics of polymorphism involves distinguishing among types of transitions and structural changes occurring in polymorphism versus those in other phenomena.
Jack David Dunitz FRS was a British chemist and widely known chemical crystallographer. He was Professor of Chemical Crystallography at the ETH Zurich from 1957 until his official retirement in 1990. He held Visiting Professorships in the United States, Israel, Japan, Canada, Spain and the United Kingdom.
Crystal engineering studies the design and synthesis of solid-state structures with desired properties through deliberate control of intermolecular interactions. It is an interdisciplinary academic field, bridging solid-state and supramolecular chemistry.
A molecular solid is a solid consisting of discrete molecules. The cohesive forces that bind the molecules together are van der Waals forces, dipole–dipole interactions, quadrupole interactions, π–π interactions, hydrogen bonding, halogen bonding, London dispersion forces, and in some molecular solids, coulombic interactions. Van der Waals, dipole interactions, quadrupole interactions, π–π interactions, hydrogen bonding, and halogen bonding are typically much weaker than the forces holding together other solids: metallic, ionic, and network solids. Intermolecular interactions typically do not involve delocalized electrons, unlike metallic and certain covalent bonds. Exceptions are charge-transfer complexes such as the tetrathiafulvane-tetracyanoquinodimethane (TTF-TCNQ), a radical ion salt. These differences in the strength of force and electronic characteristics from other types of solids give rise to the unique mechanical, electronic, and thermal properties of molecular solids.
The Cambridge Structural Database (CSD) is both a repository and a validated and curated resource for the three-dimensional structural data of molecules generally containing at least carbon and hydrogen, comprising a wide range of organic, metal-organic and organometallic molecules. The specific entries are complementary to the other crystallographic databases such as the Protein Data Bank (PDB), Inorganic Crystal Structure Database and International Centre for Diffraction Data. The data, typically obtained by X-ray crystallography and less frequently by electron diffraction or neutron diffraction, and submitted by crystallographers and chemists from around the world, are freely accessible on the Internet via the CSD's parent organization's website. The CSD is overseen by the not-for-profit incorporated company called the Cambridge Crystallographic Data Centre, CCDC.
The Cambridge Crystallographic Data Centre (CCDC) is a non-profit organisation based in Cambridge, England. Its primary activity is the compilation and maintenance of the Cambridge Structural Database, a database of small molecule crystal structures. They also perform analysis on the database for the benefit of the scientific community, and write and distribute computer software to allow others to do the same.
Materials Studio is software for simulating and modeling materials. It is developed and distributed by BIOVIA, a firm specializing in research software for computational chemistry, bioinformatics, cheminformatics, molecular dynamics simulation, and quantum mechanics.
A crystallographic database is a database specifically designed to store information about the structure of molecules and crystals. Crystals are solids having, in all three dimensions of space, a regularly repeating arrangement of atoms, ions, or molecules. They are characterized by symmetry, morphology, and directionally dependent physical properties. A crystal structure describes the arrangement of atoms, ions, or molecules in a crystal.
Molecular models of DNA structures are representations of the molecular geometry and topology of deoxyribonucleic acid (DNA) molecules using one of several means, with the aim of simplifying and presenting the essential, physical and chemical, properties of DNA molecular structures either in vivo or in vitro. These representations include closely packed spheres made of plastic, metal wires for skeletal models, graphic computations and animations by computers, artistic rendering. Computer molecular models also allow animations and molecular dynamics simulations that are very important for understanding how DNA functions in vivo.
Olex and Olex2 are versatile software for crystallographic research. Olex used to be a research project developed during PhD to implement topological analysis of polymeric chemical structures and still is widely used around the world. Olex2 is an open source project with the C++ code portable to Windows, Mac and Linux. Although the projects share the common name they are not related at the source code level.
Nuclear magnetic resonance crystallography is a method which utilizes primarily NMR spectroscopy to determine the structure of solid materials on the atomic scale. Thus, solid-state NMR spectroscopy would be used primarily, possibly supplemented by quantum chemistry calculations, powder diffraction etc. If suitable crystals can be grown, any crystallographic method would generally be preferred to determine the crystal structure comprising in case of organic compounds the molecular structures and molecular packing. The main interest in NMR crystallography is in microcrystalline materials which are amenable to this method but not to X-ray, neutron and electron diffraction. This is largely because interactions of comparably short range are measured in NMR crystallography.
Egg lysin is a protein that creates a hole in the envelope of the egg thereby allowing the sperm to pass through the envelope and fuse with the egg.
Bilbao Crystallographic Server is an open access website offering online crystallographic database and programs aimed at analyzing, calculating and visualizing problems of structural and mathematical crystallography, solid state physics and structural chemistry. Initiated in 1997 by the Materials Laboratory of the Department of Condensed Matter Physics at the University of the Basque Country, Bilbao, Spain, the Bilbao Crystallographic Server is developed and maintained by academics.
The Multipole Density Formalism is an X-ray crystallography method of electron density modelling proposed by Niels K. Hansen and Philip Coppens in 1978. Unlike the commonly used Independent Atom Model, the Hansen-Coppens Formalism presents an aspherical approach, allowing one to model the electron distribution around a nucleus separately in different directions and therefore describe numerous chemical features of a molecule inside the unit cell of an examined crystal in detail.
Margaret Cairns Etter, known informally as Peggy Etter, was an American chemist who contributed to the development of solid state chemistry for crystalline organic compounds. She is known for her work characterizing and classifying contacts by hydrogen bonds in organic compounds. Her "enlightened imagination, innovative creativity, and unfailing enthusiasm" is recognised as having a "transformative effect" in many areas of organic chemistry.
OctaDist is computer software for crystallography and inorganic chemistry program. It is mainly used for computing distortion parameters of coordination complex such as spin crossover complex (SCO), magnetic metal complex and metal–organic framework (MOF).
Mercury is a freeware developed by the Cambridge Crystallographic Data Centre, originally designed as a crystal structure visualization tool. Mercury helps three dimensional visualization of crystal structure and assists in drawing and analysis of crystal packing and intermolecular interactions. Current version Mercury can read "cif", ".mol", ".mol2", ".pdb", ".res", ".sd" and ".xyz" types of files. Mercury has its own file format with filename extension ".mryx".
