Materials Science Glossary - O

octahedral position. The void space among close-packed, hardsphere atoms or ions for which there are six nearest neighbors. An octahedron (double pyramid) is circumscribed by lines constructed from centers of adjacent spheres.

Ohm’s law. The applied voltage is equal to the product of the current and resistance; equivalently, the current density is equal to the product of the conductivity and electric field intensity.

opaque. Being impervious to the transmission of light as a result of absorption, reflection, and/or scattering of incident light.

optical fiber. A thin (5–100 um diameter) ultra-high-purity silica fiber through which information may be transmitted via photonic (light radiation) signals.

overaging. During precipitation hardening, aging beyond the point at which strength and hardness are at their maxima.

oxidation. The removal of one or more electrons from an atom, ion, or molecule.