Melamine cyanurate, also known as melamine–cyanuric acid adduct or melamine–cyanuric acid complex, is a crystalline complex formed from a 1:1 mixture of melamine and cyanuric acid. The substance is not a salt despite its non-systematic name melamine cyanurate. The complex is held together by an extensive two-dimensional network of hydrogen bonds between the two compounds, reminiscent of the guanine–cytosine base pairs found in DNA. Melamine cyanurate forms spoke-like crystals from aqueous solutions and has been implicated as a causative agent for toxicity seen in the Chinese protein export contamination and the 2007 pet food recall. This complex is cited as an example of supramolecular chemistry.

Uses

Melamine cyanurate is used as a flame retardant, most commonly in polybutylene terephthalate (PBT), polyamide 6 (nylon 6) and polyamide 6,6 (nylon 6:6). It is also used to fireproof in polyester fabrics.

Toxicity

It has been considered to be more toxic than either melamine or cyanuric acid alone. ** in rats and mice (ingested):** A toxicology study conducted after recent pet food recalls concluded that the combination of melamine and cyanuric acid in diet does lead to acute kidney injury in cats. A 2008 study produced similar experimental results in rats and characterized the melamine and cyanuric acid in contaminated pet food from the 2007 outbreak.