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Chemexper Chemical Directory catalogue chemicals CASno Structure SMILES "ChemExper". Chemxpert Database Chemxpert Chemical Database small molecules database buyers,suppliers "ChemxpertDB". 10,00000 Chemical Book East West University: commercially available compounds CASno, suppliers, properties "Chemical Book". 200,000 Chemical Register
The standard search allows querying for systematic names, trade names and synonyms and registry numbers; The advanced search allows interactive searching by chemical structure, chemical substructure, using also molecular formula and molecular weight range, CAS numbers, suppliers, etc. The search can be used to widen or restrict already found ...
Each hit provides information about synonyms, chemical properties, chemical structure including SMILES and InChI strings, bioactivity, and links to structurally related compounds and other NCBI databases like PubMed. In the text search form the database fields can be searched by adding the field name in square brackets to the search term.
Skeletal structural formula of Vitamin B 12.Many organic molecules are too complicated to be specified by a molecular formula.. The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are possibly arranged in the real three-dimensional space.
The International Chemical Identifier (InChI, pronounced / ˈ ɪ n tʃ iː / IN-chee) [3] 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.
Chemical structures are traditionally represented using lines indicating chemical bonds between atoms and drawn on paper (2D structural formulae).While these are ideal visual representations for the chemist, they are unsuitable for computational use and especially for search and storage.
Substructure search is used to retrieve from a database of chemicals those which contain the pattern of atoms and bonds specified by a user. It is implemented using a specialist type of query language and in real-world applications the search may be further constrained using logical operators on additional data held in the database.
Theories of chemical structure were first developed by August Kekulé, Archibald Scott Couper, and Aleksandr Butlerov, among others, from about 1858. [4] These theories were first to state that chemical compounds are not a random cluster of atoms and functional groups, but rather had a definite order defined by the valency of the atoms composing the molecule, giving the molecules a three ...