From The Stargate Omnipedia
A highly advanced but now long-dead civilization, predating the Goa'uld by many thousands of years. What led to the downfall of the Atonieks is unclear, but it may have had something to do with the limits of their advanced technology (such as the Atoniek armbands, which gave the wearer increased speed and strength) and the degree to which they relied on it.
The armbands only work for a short period of time, and when disabled left the wearer disoriented and vulnerable. After one use it was impossible for them to be reconnected to the same user. It is possible that the Atonieks were at war with an enemy who discovered this weakness and used it against them, forcing the society to crumble under the weight of its own arrogance.
The Atoniek civilization was studied at length by the Tok'ra archaeologist Anise, who spent much of her life searching for the armband technology.
FIRST APPEARED: N/A
Upgrades - The Tok'ra Anise brings three Atoniek armbands to SG-1 for human trials, but is convinced the technology has something to do with the species' ultimate fate.