Sodium Benzoate
chemical formula: NaC7H5O2
( coarse powder )
Sodium Benzoate is a common food additive that is used as a preservative, effectively killing most yeasts, bacteria, and fungi. In pyrotechnics, it is often ground into a fine powder and mixed with Potassium Perchlorate. This mixture is known as "Whistle Mix", a powder which produces a whistling noise when compressed into a tube and ignited.
MSDS ( Material Safety Data Sheet )