Made up of two atoms: a diatomic molecule. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "diatomic" in a sentence
"Even the structure of a diatomic molecule like O2 is not an existant thing … in other words, the structure (shape) of it does not exist in addition to the two oxygen atoms."
"Mononuclear diatomic gases don't have the broken symmetry that would be required for such quantized states."
"Their molecules are diatomic, and as such they aren't capable of achieving the quantized vibrational, rotational or rovibrational states responsible for absorption and emission of thermal radiation."