They didn't pick it, Quark did. I've been there. It's the same design as Deep Space 9, so we know the layout."
Empok Nor was a Cardassian space station located in the Trivas system, almost identical to Terok Nor (later known as Deep Space 9). The Cardassians abandoned it in 2372, leaving behind standard booby traps that targeted non-Cardassians. The station had been the site of a failed experiment that used psychotropic drugs to enhance the Cardassians' natural xenophobia. The test subjects, three members of the Third Battalion, First Order, were left on the station in stasis tubes. One stasis tube was subsequently hit by debris and the occupant died. (DS9: "Empok Nor")
In late 2373, a Starfleet salvage team from Deep Space 9 was sent to Empok Nor for spare parts, because of a recent plague of technical failures on its sister station. During the mission, the two surviving soldiers in stasis were re-awakened and killed three members of the team before they were stopped. Elim Garak was also exposed to the psychotropic drug and killed a fourth member of the team before he was neutralized by Chief Miles O'Brien. Eventually the technology was successfully salvaged. (DS9: "Empok Nor")
Later in 2374, Quark chose Empok Nor to be the site for the exchange between several Ferengi and the Dominion of Keevan for Ishka, who had been taken prisoner by the Dominion. Keevan was accidentally killed before the exchange was to take place, but Quark and the others managed to bluff the opposing side long enough for Ishka to be returned. Keevan's body was left aboard the station. (DS9: "The Magnificent Ferengi")
Finally, in 2375, Dukat brought fifty members of the Cult of the Pah-wraiths to establish a community on Empok Nor with him as their master. He had Colonel Kira Nerys kidnapped from Deep Space 9 in an effort to convert her. Dukat fled the station when his control over his followers unraveled, and the remaining cult members decided to return to Bajor with Kira aboard the USS Defiant. (DS9: "Covenant")
- See: Empok Nor personnel
According to the script for "Empok Nor", the pronunciation for Empok Nor was "EM-pahk NORE". 
In the Star Trek: Deep Space Nine - Millennium series, following the apparent destruction of DS9 with the opening of the second wormhole, Empok Nor was moved into the station's previous position by Weyoun 5, who regarded it as fulfilling a prophecy that "the Gateway" will be restored.
Several years later, the Deep Space Nine relaunch novels featured Empok Nor being towed to the Bajoran system by the Corps of Engineers. Its central core was to be used to replace that of DS9, which had been destroyed several weeks earlier.
In Star Trek Online, Empok Nor was used as a headquarters for the True Way in 2409. The station (and the mission it was part of) were removed in 2015 when the 'Cardassian Struggle' arc was revamped. Its mirror counterpart is encountered in the Badlands battlezone.