Potassium selenides

The monoselenide, K₂Se, is formed by the action of selenium on excess of potassium dissolved in liquid ammonia; with excess of selenium the tetraselenide, K₂Se₄, is produced. Each compound resembles the corresponding sodium derivative. With solutions of potassium carbonate, hydrogen selenide reacts forming a number of hydrates of the monoselenide. The heat of formation of the anhydrous mono-derivative is given as 79.4 Cal. The triselenide has been isolated, and Fabre has also described the primary selenide, KSeH.