Usually referred to as either DI water or DIW, this processed water has had virtually all mineral ions extracted, including cations such as sodium, calcium, iron, copper. Anions such as chloride and sulfate are similarly removed, and this high purity level is accomplished via the chemical process of deionization. Water is added to precision manufactured ion-exchange resins specifically designed to exchange hydrogen and hydroxide ions for dissolved minerals. Once the hydrogen/hydroxide ion exchange is complete, all material is recombined to form water. Deionization does not remove uncharged organic molecules however, though there are ionization resins that have been created specifically to remove gram-negative bacteria from water. The deionization process for mass production is typically electrodeionization, and water used for this process is generally distilled prior to deionization to remove as much of the gross matter from the unpurified, unfiltered water as possible. While specific processes may vary, the end result is the same: mineral and impurity free water for use in production or scientific study.