[cripplecreek]

deuterium, a rare type of hydrogen

Yikes, who writes this stuff. deuterium is "heavy water" which includes hydrogen obviously but hydrogen is hydrogen is hydrogen unless its something else.

[SunkenCiv]

:’) Deuterium is indeed an isotope of hydrogen. Heavy water is Deuterium monoxide.

http://en.wikipedia.org/wiki/Deuterium

[brownsfan]

“Yikes, who writes this stuff. ...”

It’s strangely worded, but correct. Deuterium is an isotope of Hydrogen. The abundant form of hydrogen has just a proton in the nucleus. Deuterium has a neutron and a proton. That’s why it’s “heavy”.