A hydroprocessing catalyst or catalyst precursor has been developed. The catalyst is a unique crystalline ammonia transition metal molybdotungstate material. The hydroprocessing using the crystalline ammonia transition metal molybdotungstate material or a decomposition product thereof may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.