Editing Potassium oxide (section)

==Term use in industry==
The chemical formula K<sub>2</sub>O (or simply 'K') is used in several industrial contexts: the [[N-P-K]] numbers for [[fertilizer]]s, in [[cement chemist notation|cement formulas]], and in [[glass batch calculation|glassmaking formulas]]. Potassium oxide is often not used directly in these products, but the amount of potassium is reported in terms of the K<sub>2</sub>O equivalent for whatever type of [[potash]] was used, such as [[potassium carbonate]]. For example, potassium oxide is about 83% [[potassium]] by weight, while [[potassium chloride]] is only 52%. [[Potassium chloride]] provides less [[potassium]] than an equal amount of potassium oxide. Thus, if a fertilizer is 30% [[potassium chloride]] by weight, its standard [[potassium]] rating, based on potassium oxide, would be only 18.8%.