Atomic Radius

Science / Periodic Table of Elements / Atomic Radius: One half the distance between nuclei of atoms of the same element, when the atoms are bound by a single covalent bond or are in a metallic crystal. The radius of atoms obtained from covalent bond lengths is called the covalent radius; the radius from interatomic distances in metallic crystals is called the metallic radius.

Polyatomic Molecule

Science / Chemistry / Polyatomic Molecule: A polyatomic molecule is an uncharged particle that contains more than two atoms. MORE

Polyatomic Ion

Science / Chemistry / Polyatomic Ion: A polyatomic ion is a charged particle that contains more than two covalently bound atoms. See Polyatomic Ions for more. MORE

Ionic Radius

Science / Chemistry / Ionic Radius: The radii of anions and cations in crystalline ionic compounds, as determined by consistently partitioning the center-to-center distance of ions in those compounds. MORE