quaternary

It's tough, however, to make these molecules if they require a quaternary carbon -- a carbon atom bonded to four other carbon atoms.

They identified chemicals that selectively damaged oligodendrocytes belong to two classes: organophosphate flame retardants and quaternary ammonium compounds.

The Salyerses’ unusual marriage is known as a quaternary marriage, and their sons are known as quaternary twins.

There are long-term risks associated with the overuse of certain disinfectants, such as quaternary ammonium compounds.

Two disinfectants known to be sprayed at Glades are called Mint and Maxim Neutral, and their ingredients that have raised concern are known as quaternary ammonium compounds, or QACs.