This monograph for Ammonium Molybdate Tetrahydrate provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Insoluble Matter, Chloride, Nitrate, Arsenate, Phosphate, Silicate, Phosphate, Sulfate, Heavy Metals, Magnesium, Potassium, and Sodium.