What color is Cyclopentadienyl nickel nitrosyl?
Oxygen Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2 . Diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. As compounds including oxides, the element makes up almost half of the Earth's crust.
Nickel(II) precatalysts Nickel(II) precatalysts are a type of catalyst used in organic reactions. Many transformations are catalyzed by nickel in organometallic chemistry and in organic synthesis. Many of these transformations invoke a low valent (generally Ni(0)) species as the active catalyst. Unfortunately, unlike its counterpart, Pd(0), Ni(0) catalysts are predominantly confined to the glovebox due to their high instability to air and water, with the most common Ni(0) catalyst being Ni(cod). Additionally, Ni(cod) is more expensive than many Ni(II) salts and the quality varies significantly amongst suppliers. To make nickel catalysis more accessible and amenable to synthesis and industrial purposes, the use of air-stable Ni(II) precursors has emerged as an important development in this area of research. This page describes the more commonly employed nickel(II) precatalysts, their synthesis for those not commercially available, and the methods for their reduction to Ni(0) complexes.