Its boiling point of 4.2 K is the lowest of any known substance.

Water is the only known non-metallic substance to expand when it freezes.

Currently, the only known substance that can increase the rate of metabolism of alcohol is fructose.

It's not any known substance apparently - something undergoing lab trials.

Yes, it has a rare biochemistry that seems to addict people faster than any other known substance, with the exception of cigarettes.

Lead is also the only known substance that Superman cannot see through with his x-ray vision.

He had seen its lines in the spectrum, and realized that they did not correspond to any known substance.

Many scientists have long been intrigued by the idea of adding a known toxic substance to water supplies to reduce cavities in teeth.

Maybe the toughest known substance to fully dry.

As with his skeleton, these claws are virtually unbreakable and can cut nearly any known substance.