Diborane is a colourless, unstable gas with what is described as a sickly-sweet, nauseating odour. It is reportedly detectable by smell at around 2.5 ppm.
Diborane is a strong reducing agent and will react explosively with most oxidising agents, including halogenated hydrocarbons.
With an autoignition temperature of 38°C, it presents a high explosion risk and can ignite spontaneously in moist air.
Diborane is highly toxic, entering the body principally by inhalation and affecting the respiratory system, central nervous system, liver and kidneys. The vapours also have an irritant effect on the skin and mucous membranes.
Diborane’s main application is as a doping agent in the semiconductor industry.