An Omega molecule is a highly unstable molecule, and theorized to be the most powerful substance known to exist.
The molecule could be synthesized with sufficient amounts of boronite ore. However, proper containment methods do not exist to prevent the violent destabilization of the molecule. The omega molecule has the ability to destroy subspace, and render warp travel impossible. The explosion of one molecule is said to be able to destroy all subspace within several light years.
There are many theories regarding the Omega molecule, mostly revolving around the Big Bang Theory, with some scientists believe the Omega molecule was the primal source of energy for the event.
As best as instruments can measure, each molecule contains the same amount of energy as a full-sized warp core. Theoretically, an Omega molecule could be so energetic, that a small chain of molecules would be able to power a civilization for an indefinite amount of time. In experiments, the Borg were able to synthesize a single molecule of Omega, which remained stable for one-trillionth of a nanosecond. The experiments destroyed a total of twenty-nine Borg vessels, and six hundred thousand drones. Borg saw the Omega molecule as "perfection," and all Borg were ordered to assimilate it at any cost.
A single Omega molecule was synthesized in the late 23rd century by a Starfleet scientist on board a classified research station. The molecule remained stable for a fraction of a second before it exploded, killing one hundred twenty-seven leading Federation scientists. An unexpected secondary effect was the creation of a subspace rupture that reached several light years. Side effects included the impossibility to create a stable warp field, complicating rescue efforts to the station.
Starfleet suppressed all knowledge of Omega, covering up the incident and authorized the Omega Directive, briefing only starship captains and flag officers.
All priorities and protocols, the Prime Directive, and Starfleet Medical protocols could be suspended during these missions.