query: instance_of guibourtinidin
supports: A counterion (pronounced as two words, i.e. "counter" "ion", and sometimes written as two words) is the ion that accompanies an ionic species in order to maintain electric neutrality. In table salt (NaCl), the sodium cation is the counterion for the chlorine anion and vice versa. Polymethines are compounds made up from an "odd" number of methine groups (CH) bound together by alternating single and double bonds. Compounds made up from an "even" number of methine groups are known as polyenes. Anthocyanins (also anthocyans; from Greek: " (anthos)" = flower + " (kyanos)" = blue) are water-soluble vacuolar pigments that may appear red, purple, or blue depending on the pH. They belong to a parent class of molecules called flavonoids synthesized via the phenylpropanoid pathway; they are odorless but flavorful, contributing to taste as a moderately astringent sensation. Anthocyanins occur in all tissues of higher plants, including leaves, stems, roots, flowers, and fruits. Anthoxanthins are clear, white to yellow counterparts of anthocyanins occurring in plants. Anthocyanins are derived from anthocyanidins by adding sugars. Anthocyanidins are common plant pigments. They are the sugar-free counterparts of anthocyanins based on the flavylium ion or 2-phenylchromenylium, which is a type of oxonium ion (chromenylium is referred also to as benzopyrylium). They form a large group of polymethine dye. In particular anthocyanidins are salt derivatives of the 2-phenylchromenylium cation, also known as flavylium cation. As shown in the figure below, the phenyl group at the 2-position can carry different substituents. The counterion of the flavylium cation is mostly chloride. With this positive charge, the anthocyanidins differ from other flavonoids. In organic chemistry and biochemistry, a substituent is an atom or group of atoms which replaces hydrogen atom on the parent chain of a hydrocarbon, becoming a moiety of the resultant new molecule. The terms substituent, side chain, group, branch, or pendant group are used almost interchangeably to describe branches from a parent structure, though certain distinctions are made in the context of polymer chemistry. In polymers, side chains extend from a backbone structure. In proteins, side chains are attached to the alpha carbon atoms of the amino acid backbone. In chemistry, an oxonium ion is any oxygen cation with three bonds. The simplest oxonium ion is the hydronium ion HO. Another class of oxonium ions frequently encountered in organic chemistry is the oxocarbenium ions, obtained by protonation or alkylation of a carbonyl group e.g. RC=OR which forms a resonance structure with the fully-fledged carbocation RCOR and is therefore especially stable: The chloride ion is the anion (negatively charged ion) Cl. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salts such as sodium chloride are often very soluble in water. It is an essential electrolyte located in all body fluids responsible for maintaining acid/base balance, transmitting nerve impulses and regulating fluid in and out of cells. Less frequently, the word "chloride" may also form part of the "common" name of chemical compounds in which one or more chlorine atoms are covalently bonded. For example, methyl chloride, with the standard name chloromethane (see IUPAC books) is an organic compound with a covalent CCl bond in which the chlorine is not an anion. Guibourtinidin is a anthocyanidin .
candidates: acid base bond branch cation chain chloride class counter electron flower group hydrocarbon hydrogen ion molecule number part plant polymer salt side single stable standard two vice water word
answer: cation