The compound with the formula K2O is called potassium oxide. It is an ionic compound consisting of potassium cations (K+) and oxide anions (O2-). Potassium oxide is a white or grayish-white solid that is highly reactive and hygroscopic, meaning it readily absorbs moisture from the air. It is commonly used as a fertilizer, a source of potassium in various industrial processes, and as an additive in the production of glass and ceramics.