Rhodium nitrite ((NH4)3Rh(NO2)6) was a chemical compound, which when combined with selenium, could be reformulated and with some work synthesized to produce the biogenic weapon cobalt diselenide.
In 2373, the Maquis captured two Bolian freighters carrying several thousand tons of rhodium nitrite and selenium, which was relatively low-value cargo. (DS9: "For the Uniform")