Sodium nitrate is a white, powdery compound that is known for its reactivity and solubility in water. It is also referred to as Chile saltpeter, sodium saltpeter, soda niter, cubic niter and nitratine. The compound occurs naturally in many leafy, green vegetables, and is used in several industrial applications. These include pesticides, food preservatives, fireworks, and fertilizers.
Many different pesticides utilize sodium nitrate, including rodenticides (for killing rodents like mice and rats), insecticides (for killing insects and other bugs) and predacides (for killing large pests like raccoons and skunks). Sodium nitrate does not directly poison these pests, but instead, it chemically reacts with other substances (like sulfur) to combust charcoal, according to the Environmental Protection Agency at epa.gov. All of this occurs inside of a cartridge, which then seeps out a toxic gas that is produced by the combustion.
Sodium nitrate is also known for its antimicrobial properties. For this reason, it is commonly used for preserving foods, particularly when it comes to curing meats, according to edinformatics.com. Sodium nitrate is not harmful when ingested (as mentioned above, it is found naturally in some vegetables); however, you should make sure not to confuse the compound with sodium nitrite; another preservative, which has been known to produce carcinogenic effects in certain circumstances.
The brilliant colors associated with fireworks are the result of burning metal salts, such as calcium chloride, barium chloride and sodium nitrate. According to scifun.org, the atoms in each salt generate specific colors as they combust, which is a function of how much energy they release. When sodium nitrate combusts, the heated sodium electrons become excited, and eventually release energy at approximately 200 kj/mol. This happens to be the energy amount that produces the color yellow, and for that reason firework makers use sodium nitrate to generate yellow flames and sparks.
Sodium nitrate is also used as an ingredient in many fertilizers, as a way to increase nitrogen content in soil. In addition to helping prevent soil erosion, nitrogen helps roots grow thick and strong by increasing carbon production in plants, which in turn increases biomass. The majority of mixed fertilizers include sodium nitrate, or another nitrogen-based compound, as one of their three main ingredients, with the other two substances being phosphorus and potassium (although it is also possible to a buy a strictly nitrogen-based fertilizer, if you want). According to ncagr.gov, when choosing a mixed fertilizer, the amount of nitrogen will be the first number listed on the packaging, and usually represents a percentage amount (the second two numbers will indicate phosphorus and potassium content).