Ammonium heptamolybdate, also known as ammonium molybdate(VI), is a commonly used compound in analytical chemistry and industrial applications. It is primarily used as a reagent for the determination of phosphate, arsenate, and silicate in various samples. The solubility of ammonium heptamolybdate in water is moderate.

At room temperature (around 25 degrees Celsius or 77 degrees Fahrenheit), the solubility of ammonium heptamolybdate is approximately 80 grams per 100 milliliters of water. It means that 80 grams of ammonium heptamolybdate can dissolve in 100 milliliters of water at this temperature. However, it’s important to note that the solubility may vary slightly depending on the purity of the compound and the specific conditions.