Ho3

Ho3 is an alphanumeric designation that can refer to several different concepts depending on context. In chemistry and materials science, Ho3+ denotes the trivalent holmium ion, the common oxidation state of holmium in compounds. As Ho3+ ions, holmium participates in coordination chemistry and is used to dope solid-state hosts for optical and magnetic applications. Holmium-doped materials, such as Ho:YAG and Ho:YLF crystals, are well known for infrared emission in the ~2 micrometer region and are used in solid-state lasers and optical amplifiers. The ion’s electronic transitions give rise to characteristic absorption and emission features exploited in spectroscopy, medical devices, and communications.

In isotopic notation, Ho-3 would indicate an isotope of holmium with mass number 3. No such isotope is known or observed; the only stable holmium isotope is Ho-165, and all other holmium isotopes are short-lived. An Ho-3 state would be extraordinarily light and is not supported by current nuclear physics, so Ho-3 does not refer to a physically observed nucleus in practice.

In other contexts, Ho3 may appear as an identifier or model number for products, laboratory equipment, software, or project codes. Without context, the meaning is ambiguous, and references should specify the domain (chemistry, physics, engineering, or information technology) to avoid confusion.