What is Nickel(II) oxide?
'''Nickel(II) oxide''', also known as '''nickelous oxide''', is a [[chemical compound]]. Its chemical formula is NiO. It contains [[nickel]] in its +2 [[oxidation state]]. It also contains [[oxide]] [[ion]]s. ==Properties== Nickel(II) oxide is a light green solid. It does not dissolve in water. Sometimes it is gray because all of the nickel is not in the +2 oxidation state. It reacts with [[acid]]s to make nickel(II) salts. For example, it reacts with [[hydrochloric acid]] to make [[nickel(II) chloride]]. It does not react with [[base (chemistry)|bases]] easily. ==Preparation== Nickel(II) oxide can be made by heating nickel powder in air at {{convert|400|C|F}}. This normally makes a black nickel oxide. It also can be made by reacting nickel with water at {{convert|1000|C|F}}. The simplest way to make it is to heat [[nickel(II) hydroxide]], [[nickel(II) carbonate]], or [[nickel(II) nitrate]]. ==Uses== It is used to make [[alloy]]s. It is also used in [[ceramic]]s. It is used to make other nickel compounds. ==Safety== Nickel(II) oxide can irritate skin and make problems when breathed in. ==Related pages== *[[Nickel(II) sulfate]] [[Category:Nickel compounds]] [[Category:Oxides]]