2-croconate is a divalent

Valence (chemistry)

In chemistry, valence, also known as valency or valence number, is a measure of the number of bonds formed by an atom of a given element. "Valence" can be defined as the number of valence bonds...

 anion with chemical formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

  or ((N≡C-)₂C=)(C₅O₄)²⁻. It is one of the pseudo-oxocarbon anion

Pseudo-oxocarbon anion

In chemistry, the term pseudo-oxocarbon anion is used to refer to a negative ion that is conceptually derived from an oxocarbon anion through replacement of one or more of the basic oxygen atoms by chemically similar elements or functional groups, such as sulfur , selenium , or dicyanomethylene...

s, as it can be described as a derivative of the croconate

Croconic acid

Croconic acid or 4,5-dihydroxycyclopentenetrione is a chemical compound with formula C5H2O5 or 32. It has a cyclopentene backbone with two hydroxyl groups adjacent to the double bond and three ketone groups on the remaining carbon atoms...

 oxocarbon anion

Oxocarbon anion

In chemistry, an oxocarbon anion is a negative ion consisting solely of carbon and oxygen atoms, and therefore having the general formula CxOyn− for some integers x, y, and n....

  through the replacement of one oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 atom by a dicyanomethylene group

Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...

 =C(-C≡N)₂.

The anion was syntesized and characterized by A. Fatiadi

Alexander J. Fatiadi

Alexander J. Fatiadi is a chemist.He obtained his masters from the George Washington University, Washington DC . He has worked at the National Bureau of Standards.-Selected publications:...

 in 1980, by hydrolysis of croconate violet

Croconate violet

Croconate violet or 1,3-biscroconate is a divalent anion with chemical formula or 22−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of two oxygen atoms by dicyanomethylene groups =C2...

 treated with potassium hydroxide

Potassium hydroxide

Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...

. It gives an orange solution in water.

See also

• Croconate violet
  Croconate violet
  Croconate violet or 1,3-biscroconate is a divalent anion with chemical formula or 22−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of two oxygen atoms by dicyanomethylene groups =C2...
  
  , 1,3-bis(dicyanomethylene)croconate
• Croconate blue
  Croconate blue
  Croconate blue or 1,2,3-triscroconate is a divalent anion with chemical formula or 32−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of three oxygen atoms by dicyanomethylene groups =C2...
  
  , 1,2,3-tris(dicyanomethylene)croconate
• 1,2-Bis(dicyanomethylene)squarate
  1,2-Bis(dicyanomethylene)squarate
  1,2-Bissquarate is a divalent anion with chemical formula or 22−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the squarate oxocarbon anion through the replacement of two adjacent oxygen atoms by dicyanomethylene groups =C2.The anion can be obtained...
  
  
• 1,3-Bis(dicyanomethylene)squarate
  1,3-Bis(dicyanomethylene)squarate
  1,3-Bissquarate is a divalent anion with chemical formula or 22−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the squarate oxocarbon anion through the replacement of two opposite oxygen atoms by dicyanomethylene groups =C2.The anion can be obtained...