Chemical characteristics
Bismuth is stable to both dry and moist air at ordinary temperatures. When red-hot, it reacts with water to make bismuth(III) oxide. 2 Bi + 3 H2O → Bi2O3 + 3 H2It reacts with fluorine to make bismuth(V) fluoride at 500 °C or bismuth(III) fluoride at lower temperatures (typically from Bi melts); with other halogens it yields only bismuth(III) halides. The trihalides are corrosive and easily react with moisture, forming oxyhalides with the formula BiOX. 4 Bi + 6 X2 → 4 BiX3 (X = F, Cl, Br, I)
4 BiX3 + 2 O2 → 4 BiOX + 4 X2Bismuth dissolves in concentrated sulfuric acid to make bismuth(III) sulfate and sulfur dioxide. 6 H2SO4 + 2 Bi → 6 H2O + Bi2(SO4)3 + 3 SO2It reacts with nitric acid to make bismuth(III) nitrate (which decomposes into nitrogen dioxide when heated). Bi + 6 HNO3 → 3 H2O + 3 NO2 + Bi(NO3)3It also dissolves in hydrochloric acid, but only with oxygen present. 4 Bi + 3 O2 + 12 HCl → 4 BiCl3 + 6 H2OIt is used as a transmetalating agent in the synthesis of alkaline-earth metal complexes:

3 Ba + 2 BiPh3 → 3 BaPh2 + 2 Bi

Isotopes
The only primordial isotope of bismuth, bismuth-209, was traditionally regarded as the heaviest stable isotope, but it had long been suspected to be unstable on theoretical grounds.
Bismuth subnitrate is a component of glazes that produces an iridescence and is used as a pigment in paint. Bismuth telluride is a semiconductor and an excellent thermoelectric material. Bi2Te3 diodes are used in mobile refrigerators, CPU coolers, and as detectors in infrared spectrophotometers. Bismuth oxide, in its delta form, is a solid electrolyte for oxygen. This form normally breaks down below a high-temperature threshold, but can be electrodeposited well below this temperature in a highly alkaline solution. Bismuth germanate is a scintillator, widely used in X-ray and gamma ray detectors. Bismuth vanadate is an opaque yellow pigment used by some artists oil, acrylic, and watercolor paint companies, primarily as a replacement for the more toxic cadmium sulfide yellows in the greenish-yellow (lemon) to orange-toned yellow range. It performs practically identically to the cadmium pigments, such as in terms of resistance to degradation from UV exposure, opacity, tinting strength, and lack of reactivity when mixed with other pigments. The most commonly-used variety by artists paint makers is lemon in color. In addition to being a replacement for several cadmium yellows, it also serves as a non-toxic visual replacement for the older chromate pigments made with zinc, lead, and strontium. If a green pigment and barium sulfate (for increased transparency) are added it can also serve as a replacement for barium chromate, which possesses a more greenish cast than the others.