Figure 3. Synthesis Apparatus. The representation of the apparatus used to synthesize the compound. A hydrogen gas generator (A) provides H2 gas that is sparged through a fllter stone in deionized, distilled water (B), where the hydrogen gas and water vapor are transported into a reaction vessel (C) with the substrate. Two tungsten electrodes (D) create a captive plasma H− gas via a constant current high-voltage power supply (E). Vessel evacuation, purge and sealing were performed using a mechanical valve (F). The resultant actions interstitially embed the hydride anions created by the plasma into the substrate.