On the basis of an X-ray diffraction and thermal analysis investigation of melt-spun Al-transition metal (Al-TM) alloys, the authors report the formation of a highly stable and well-ordered pure icosahedral (i) phase in Al80TM120-xTM2x(TM1 = V, Cr; TM2 = Fe, Co). The superior i-phase formation over that in the binary Al-TM alloys is interpreted in terms of the distribution of TM sites known to exist in this phase. A comparison of the i-phase formation ranges indicates the presence of two distinct classes of TM sites and a strong interaction between adjacent TM sites.