Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 2892-51-5, Whether you call it Squaric Acid, 3 -4-Dihydroxy-3-cyclobutene-1 -2-dione or Diketocyclobutenediol you can be assured the Squaric Acid products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.