Boron trichloride is a starting material for the production of elemental boron. Fuels include aluminium, magnesium, titanium, zinc, silicon, and boron. These employ boron, antimony, or halogenated hydrocarbon compounds. All other forms of boron nitride are crystalline. Such elements include germanium, zinc, platinum, silicon, and boron. The main micronutrients are molybdenum, zinc, boron, and copper. Pure cubic boron nitride is transparent or slightly amber. Low-pressure deposition of thin films of cubic boron nitride is possible. Little is known on melting behavior of boron nitride. Metallic conductivity has been achieved by heavy doping with boron, aluminium or nitrogen. There are a few variations of 2D boron nitride structure. Green pyrotechnic flares can use a mix ratio 75&colon;25 of boron and potassium nitrate. The common oxide of boron (BO) is weakly acidic. The Big Bang also produced small amounts of lithium, beryllium and perhaps boron. He, and 0.01% deuterium, with only tiny traces of lithium, beryllium, and perhaps boron.