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  2. Alkyne - Wikipedia

    en.wikipedia.org/wiki/Alkyne

    A 3D model of ethyne (), the simplest alkyneIn organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. [1] The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula C n H 2n−2.

  3. Heteroatom - Wikipedia

    en.wikipedia.org/wiki/Heteroatom

    It can also be used with highly specific meanings in specialised contexts. In the description of protein structure, in particular in the Protein Data Bank file format, a heteroatom record (HETATM) describes an atom as belonging to a small molecule cofactor rather than being part of a biopolymer chain.

  4. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...

  5. Atoms in molecules - Wikipedia

    en.wikipedia.org/wiki/Atoms_in_molecules

    In quantum chemistry, the quantum theory of atoms in molecules (QTAIM), sometimes referred to as atoms in molecules (AIM), is a model of molecular and condensed matter electronic systems (such as crystals) in which the principal objects of molecular structure - atoms and bonds - are natural expressions of a system's observable electron density distribution function.

  6. Terminal and nonterminal symbols - Wikipedia

    en.wikipedia.org/wiki/Terminal_and_nonterminal...

    Nonterminal symbols are those symbols that can be replaced. They may also be called simply syntactic variables. A formal grammar includes a start symbol, a designated member of the set of nonterminals from which all the strings in the language may be derived by successive applications of the production rules.

  7. Adatom - Wikipedia

    en.wikipedia.org/wiki/Adatom

    This term is used in surface chemistry and epitaxy, when describing single atoms lying on surfaces and surface roughness. The word is a portmanteau of "adsorbed atom". A single atom, a cluster of atoms, or a molecule or cluster of molecules may all be referred to by the general term "adparticle". This is often a thermodynamically unfavorable state.

  8. N-terminus - Wikipedia

    en.wikipedia.org/wiki/N-terminus

    The N-terminus is the first part of the protein that exits the ribosome during protein biosynthesis.It often contains signal peptide sequences, "intracellular postal codes" that direct delivery of the protein to the proper organelle.

  9. Unpaired electron - Wikipedia

    en.wikipedia.org/wiki/Unpaired_electron

    In chemistry, an unpaired electron is an electron that occupies an orbital of an atom singly, rather than as part of an electron pair. Each atomic orbital of an atom (specified by the three quantum numbers n, l and m) has a capacity to contain two electrons (electron pair) with opposite spins.