Answer
$(0,0,3),(0,1,0),(2,0,0),(2,1,0),(2,0,3),(0,1,3).$
Work Step by Step
If the opposite vertices of a rectangular box are: $(a,b,c)$ and $(d,e,f)$ then the other six vertices will have coordinates (because the other $6$ vertices must "inherit" each coordinate from either of the opposite vertices): $(a,b,f),(a,e,c),(d,b,c),(d,e,c),(d,b,f),(a,e,f).$ (See image.)
Hence here the other vertices are: $(0,0,3),(0,1,0),(2,0,0),(2,1,0),(2,0,3),(0,1,3).$
