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Chemical Table File
Chemical table file (CT File) is a family of text-based chemical file formats that describe molecules and chemical reactions. One format, for example, lists each atom in a molecule, the x-y-z coordinates of that atom, and the bonds among the atoms. File formats There are several file formats in the family. The formats were created by MDL Information Systems (MDL), which was acquired by Symyx Technologies then merged with Accelrys Corp., and now called BIOVIA, a subsidiary of Dassault Systemes of Dassault Group. CT File is an open format, BIOVIA publishes its specification. BIOVIA requires users to register to download the CTFile format specifications. Molfile An MDL Molfile is a file format for holding information about the atoms, bonds, connectivity and coordinates of a molecule. The molfile consists of some header information, the Connection Table (CT) containing atom info, then bond connections and types, followed by sections for more complex information. The molfil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical File Format
A chemical file format is a type of data file which is used specifically to depicting molecular data. One of the most widely used is the chemical table file format, which is similar to ''Structure Data Format'' (SDF) files. They are text files that represent multiple chemical structure records and associated data fields. The XYZ file format is a simple format that usually gives the number of atoms in the first line, a comment on the second, followed by a number of lines with atomic symbols (or atomic numbers) and cartesian coordinates. The Protein Data Bank Format is commonly used for proteins but is also used for other types of molecules. There are many other types which are detailed below. Various software systems are available to convert from one format to another. Distinguishing formats Chemical information is usually provided as files or streams and many formats have been created, with varying degrees of documentation. The format is indicated in three ways:(see ) * ''f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Bond
A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules and crystals. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing of electrons as in covalent bonds. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force and hydrogen bonding. Strong chemical bonding arises from the sharing or transfer of electrons between the participating atoms. Since opposite electric charges attract, the negatively charged electrons surrounding the nucleus and the positively charged protons within a nucleus attract each other. An electron positioned between two nuclei will be attracted to both of them, and the nuclei will be attracted toward electrons in this position. This attraction constitu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical File Format
A chemical file format is a type of data file which is used specifically to depicting molecular data. One of the most widely used is the chemical table file format, which is similar to ''Structure Data Format'' (SDF) files. They are text files that represent multiple chemical structure records and associated data fields. The XYZ file format is a simple format that usually gives the number of atoms in the first line, a comment on the second, followed by a number of lines with atomic symbols (or atomic numbers) and cartesian coordinates. The Protein Data Bank Format is commonly used for proteins but is also used for other types of molecules. There are many other types which are detailed below. Various software systems are available to convert from one format to another. Distinguishing formats Chemical information is usually provided as files or streams and many formats have been created, with varying degrees of documentation. The format is indicated in three ways:(see ) * ''f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Markush Structure
A Markush structure is a representation of chemical structure used to indicate a group of related chemical compounds. They are commonly used in chemistry texts and in patent claims. Markush structures are depicted with multiple independently variable groups, such as R groups in which a side chain can have varying structure. This more general depiction of the molecule, versus detailing every atom in the molecule, is used to protect intellectual property. The company which applies for a patent makes a general claim for the usage of the molecule without revealing to their competitors the exact molecule for which they are declaring a useful application. History Markush structures are named after Eugene A. Markush, founder of the Pharma Chemical Corporation in New Jersey. He was involved in a legal case that set a precedent for generic chemical structure patent filing. The patent filing was US Application 611,637, filed January 9, 1923. Markush was awarded a patent from the US Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
InChI
The International Chemical Identifier (InChI or ) is a textual identifier for chemical substances, designed to provide a standard way to encode molecular information and to facilitate the search for such information in databases and on the web. Initially developed by the International Union of Pure and Applied Chemistry (IUPAC) and National Institute of Standards and Technology (NIST) from 2000 to 2005, the format and algorithms are non-proprietary. Since May 2009, it has been developed by the InChI Trust, a nonprofit charity from the United Kingdom which works to implement and promote the use of InChI. The identifiers describe chemical substances in terms of ''layers'' of information — the atoms and their bond connectivity, tautomeric information, isotope information, stereochemistry, and electronic charge information. Not all layers have to be provided; for instance, the tautomer layer can be omitted if that type of information is not relevant to the particular applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMILES
The simplified molecular-input line-entry system (SMILES) is a specification in the form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules. The original SMILES specification was initiated in the 1980s. It has since been modified and extended. In 2007, an open standard called OpenSMILES was developed in the open-source chemistry community. History The original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. Acknowledged for their parts in the early development were "Gilman Veith and Rose Russo (USEPA) and Albert Leo and Corwin Hansch (Pomona College) for supporting the work, and Arthur Weininger (Pomona; Daylight CIS) and Jeremy Scofield (Cedar River Software, Renton, WA) for assistance in programming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delimiter
A delimiter is a sequence of one or more characters for specifying the boundary between separate, independent regions in plain text, mathematical expressions or other data streams. An example of a delimiter is the comma character, which acts as a ''field delimiter'' in a sequence of comma-separated values. Another example of a delimiter is the time gap used to separate letters and words in the transmission of Morse code. In mathematics, delimiters are often used to specify the scope of an operation, and can occur both as isolated symbols (e.g., colon in "1 : 4") and as a pair of opposing-looking symbols (e.g., angled brackets in \langle a, b \rangle). Delimiters represent one of various means of specifying boundaries in a data stream. Declarative notation, for example, is an alternate method that uses a length field at the start of a data stream to specify the number of characters that the data stream contains. describing the method in Hollerith notation under the Fortran p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molfile
Chemical table file (CT File) is a family of text-based chemical file formats that describe molecules and chemical reactions. One format, for example, lists each atom in a molecule, the x-y-z coordinates of that atom, and the bonds among the atoms. File formats There are several file formats in the family. The formats were created by MDL Information Systems (MDL), which was acquired by Symyx Technologies then merged with Accelrys Corp., and now called BIOVIA, a subsidiary of Dassault Systemes of Dassault Group. CT File is an open format, BIOVIA publishes its specification. BIOVIA requires users to register to download the CTFile format specifications. Molfile An MDL Molfile is a file format for holding information about the atoms, bonds, connectivity and coordinates of a molecule. The molfile consists of some header information, the Connection Table (CT) containing atom info, then bond connections and types, followed by sections for more complex information. The molfile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angstrom
The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.merriam-webster.com/dictionary/angstrom. (, ; , ) or ångström is a metric unit of length equal to m; that is, one ten-billionth ( US) of a metre, a hundred-millionth of a centimetre,Entry "angstrom" in the Oxford English Dictionary, 2nd edition (1986). Retrieved on 2021-11-22 from https://www.oed.com/oed2/00008552. 0.1 nanometre, or 100 picometres. Its symbol is Å, a letter of the Swedish alphabet. The unit is named after the Swedish physicist Anders Jonas Ångström (1814–1874). The angstrom is often used in the natural sciences and technology to express sizes of atoms, molecules, microscopic biological structures, and lengths of chemical bonds, arrangement of atoms in crystals,Arturas Vailionis (2015):Geometry of Crystals Lect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MDL Information Systems
MDL Information Systems, Inc. was a provider of R&D informatics products for the life sciences and chemicals industries. The company was launched as a computer-aided drug design firm (originally named Molecular Design Limited, Inc.) in January 1978 in Hayward, California. The company was acquired by Symyx Technologies, Inc. in 2007. Subsequently Accelrys merged with Symyx. The Accelrys name was retained for the combined company. In 2014 Accelrys was acquired by Dassault Systemes. The Accelrys business unit was renamed BIOVIA. History Molecular Design Limited, Inc. was founded by Stuart Marson and W. Todd Wipke in 1978. With 15 years of research on computer synthesis at the University of California, Santa Cruz, Wipke, with Marson, fresh from a Ph.D. at Stanford University and a postdoctoral stint at the University of California, Berkeley, were convinced that computer-assisted molecular design was possible as a commercial enterprise.C&EN, June 18, 1979 Employee #3 was Stephen Peaco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematica
Wolfram Mathematica is a software system with built-in libraries for several areas of technical computing that allow machine learning, statistics, symbolic computation, data manipulation, network analysis, time series analysis, NLP, optimization, plotting functions and various types of data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other programming languages. It was conceived by Stephen Wolfram, and is developed by Wolfram Research of Champaign, Illinois. The Wolfram Language is the programming language used in ''Mathematica''. Mathematica 1.0 was released on June 23, 1988 in Champaign, Illinois and Santa Clara, California. __TOC__ Notebook interface Wolfram Mathematica (called ''Mathematica'' by some of its users) is split into two parts: the kernel and the front end. The kernel interprets expressions (Wolfram Language code) and returns result expressions, which can then be displayed by the front end. The origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
