In the structure,it is easy that first H enters crystal lattice,and the entering of the second H into crystal lattice needs higher energy than the first one.However,the third H entering is easier than the second one because the triangle structure is very stable.Before V3H+ is formed,the V2H+ is formed necessarily.This inhibits the formation of V3H+.on the analogy of the defects formation mechanism,VH+ is corresponds to the 2920 cm-1 peak V2H+ to the 2955 cm-1 peak,and V3H+ to the 2850 cm-1 preak