Invidium was a substance with many uses, although it was very dangerous if handled improperly. It was an almost permeable compound used in biological containment vessels for operations involving a type of virus culture. It was not normally detected by standard scans, could exist in a nitrogen-oxygen atmosphere, and could alter the molecular structure of glass. It was one of only five substances with these properties. The substance became inert below −200 °C.
In the 23rd century, the Federation used invidium in its medical containment fields, although this practice changed with the advent of newer and safer technology. By the mid-24th century, invidium hadn't been used "for decades", before many of the systems the substance could affect were invented, such as the transporter or a magnetic capacitor.
In 2366, the USS Enterprise-D was transporting a shipment from the Mikulaks when Lieutenant Reginald Barclay broke a container containing invidium. Lieutenant jg Duffy and Miles O'Brien were handling the container and were unknowingly contaminated with invidium. Through them, the substance then began wreaking havoc on different ship's systems, including causing the replicators to malfunction, causing a drinking glass to melt in Duffy's hand, and, more seriously, physically jamming the matter/antimatter injectors, almost destroying the Enterprise. Cooling the injectors allowed them to come back online.
The engineering team realized the Mikulaks still used invidium and took appropriate measures to repair the damage caused to the ship. Afterward, the ship was decontaminated at Starbase 121. (TNG: "Hollow Pursuits")