However, the large difference in melting points and vapor pressures between Mg and Ni make difficult the formation of high quality Mg2Ni [7].
It is shown that effects which render the chainfolding in lamellae more difficult, enhance the formation of the γ-modification.
It is difficult for the formation of the core of Cu in the reaction solution when the ratio of ligand is too high.
Moreover, it was found that the Pt1/Cu (111) binds CO more strongly than that of Cu (111) one and thus leading to the difficult for the formation of CO.
When R is not sterically demanding, or when the second olefin is too substituted, the evolution of B syn into C is more difficult and the formation of D becomes competitive, thus leading to the formation of 3.[ 3d– f, 10] The same mechanistic manifold is operative for substrate 4 a, thus leading to the formation of 5 and 6.
The separation of methanol and DMC is important but difficult due to the formation of an azeotropic mixture.
With the increase in content of any second component (PEN or PET), the crystallization process in the as-spun fibres becomes difficult, because of the formation of random copolymers via a transesterification reaction occurring between PET and PEN molecules.
It is difficult to detect the formation of Cd complexes or modification of the structure of HAP by Cd due to the similar ionic radii of Ca (0.99 Å) and Cd (0.97 Å).
In fact, by conventional methods, used for EDF fabrication, it is difficult to avoid the formation of Er 3+ ion pairs and the amount of glass modifiers must be maximized to reach the suited optical properties [13].
The casting of iron components was initially very difficult due to the formation of lustrous carbon defects on the surface and subsurface carbonaceous inclusions, which were only revealed on machining.
