Copper benzoate is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

Cu(C₆H₅CO₂)₂(H₂O)_x. These

coordination complex A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

es are derived from the

cupric Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange c ...

ion and the

conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid gives a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as it loses a hydrogen ion in the reve ...

benzoic acid Benzoic acid () is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. The benzoyl group is often abbreviated "Bz" (not to be confused with "Bn," which ...

. Many derivatives are known with diverse ancillary ligands. It has found some use as a source of blue light in

fireworks Fireworks are Explosive, low explosive Pyrotechnics, pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large numbe ...

Preparation

In laboratory, copper benzoate can be made by combining aqueous solutions of

potassium benzoate Potassium benzoate (E212), the potassium salt of benzoic acid, is a food preservative that inhibits the growth of mold, yeast and some bacteria. It works best in low- pH products, below 4.5, where it exists as benzoic acid. Acidic foods and bev ...

with

copper sulfate Copper sulfate may refer to: * Copper(II) sulfate, CuSO4, a common, greenish blue compound used as a fungicide and herbicide * Copper(I) sulfate, Cu2SO4, an unstable white solid which is uncommonly used {{chemistry index Copper compounds ...

. Hydrated copper benzoate precipitates as a pale blue solid: :

Uses

The primary use of this compound is in the production of a blue flame in fireworks. Copper benzoate made from sodium benzoate for use in fireworks may result in strong yellow dilution of the flame unless the precipitate is carefully washed to remove sodium ions (which emit bright yellow). Emission from potassium does not complicate the emission spectrum.

Structure

Copper(II) benzoate exists in at least two structural forms, depending on the degree of hydration. As in

copper(II) acetate Copper(II) acetate, also referred to as cupric acetate, is the chemical compound with the formula where is acetate (). The hydrated derivative, , which contains one molecule of water for each copper atom, is available commercially. Anhydrous co ...

, one form of copper benzoate adopts a "Chinese lantern" structure, wherein a pair of copper centers are linked by four bridging carboxylate ligands. Typically, one site on each copper center is occupied by water, which can be replaced by other ligands. A hydrated form is also known, wherein each Cu(II) centre is bound to four water ligands and a bidentate O,O-benzoate.{{cite journal, doi=10.1143/JPSJ.18.117 , title=Crystal Structure of Cupric Benzoate Trihydrate Cu(C₆H₅COO)₂3H₂O , date=1963 , last1=Koizumi , first1=Hideo , last2=Osaki , first2=Kenji , last3=Watanabé , first3=Tokunosuké , journal=Journal of the Physical Society of Japan , volume=18 , issue=1 , pages=117–124 , bibcode=1963JPSJ...18..117K

Related compounds

* Copper salicylate * Phenylcopper

References

Copper(II) compounds Benzoates