The present invention describes a new class of trinuclear hafnium complexes comprising two hexadentate azainositol carboxylic acid ligands, methods for their preparation and their use as X-ray contrast agents.本發明闡述一種新種類之包括兩個六齒氮雜肌醇羧酸配體之三核鉿錯合物、其製備方法及其作為X射線造影劑之用途。