Dichromate

Dichromate ( Cr2O72– ) was a chemical ion containing chromium and oxygen.

The "Silver Blood", discovered by the USS Voyager on a Y-class planet in 2374, were composed of deuterium, hydrogen sulfate, dichromates, and proteins. 

In 2375 aboard the USS Voyager created from the Silver Blood, The Doctor used a dichromate catalyst to revert that B'Elanna Torres back into her original fluid state. Dichromates were among the debris of the duplicate Voyager, detected by the original after the Silver Blood vessel was destroyed.