A process for preparing the crystalline modification II of the anhydrate of boscalid is provided, the process comprising heating a solid boscalid starting material to an elevated temperature, the elevated temperature being below the melting point of the solid boscalid starting material and sufficient to preferentially form the crystalline modification II of the anhydrate of boscalid.提供了一種製備白克列無水物的結晶變體II之方法，該方法包括將固體白克列起始材料加熱到高溫，其中該高溫低於該固體白克列起始材料的熔點，並足以優先形成白克列無水物的結晶變體II。
