There has been a broad array of other materials intercalated into the Bi₂Sr₂Ca_n-1Cu_nO_2n+4 system.  Lithium, for example, can be easily intercalated by electrochemical methods,^{68, 71} although it is unclear if this small cation resides between the bismuth-oxide layers.  Most other intercalated materials do reside between the bismuth-oxide layers due to their size.  Metal phthalocyanines,^72-83 for instance, are much too bulky to reside in any other location.  These large macrocyclic molecules containing metal centers like Cu or Ni are incorporated between the adjacent bismuth-oxide layers where metals possibly coordinate with the 6s² lone pairs. 

The salts of HgI₂^61-64 and AgI^56-60 are two other materials that have been intercalated into the structure of the Bi₂Sr₂Ca_n-1Cu_nO_2n+4 system.  Intercalation of these systems is accomplished by reacting the superconductor with either HgI₂ and AgI in an evacuated Pyrex or quartz tube.  Iodine is also placed in this tube as a transporting agent.  These materials also expand the lattice of the superconductor, but by distances more than twice that of iodine.  The expansion of the lattice does not seem to affect drastically the transition temperature upon intercalation in any of the bismuth cuprate superconductors.