Gunpowder is a mixture of several ingredients, including SULFUR, NITRE, SULPHUR, SALTPETER, and niter. SULFUR is a yellow, non-metallic element with 6 letters, while NITRE is an oxide of nitrogen with 5 letters. SULPHUR is another form of SULFUR with 7 letters, and SALTPETER is a potassium nitrate with 9 letters. Lastly, niter is a mineral form of potassium nitrate with 5 letters. All of these ingredients are essential components of gunpowder, which has been used for centuries in weapons and fireworks.