Riemann's green is a green pigment ZnO.CoO, which is obtained by heating a mixture of zinc oxide and cobalt nitrate or by the reaction of cobalt nitrate with either or zinc sulphate.
This picture develops a clear understanding.

Not even a single member ofAksionov'sfamily was concerned about his well-being when he was at his lowest.Along with the judges of the court even his wife did not trust him.Hewas imprisoned for the crime he did not commit.With time he learnt to forgive people, but he did not forget their mistreatment.
Yes, a vector which has zero magnitude is also a vector in case of two vectors travelling in opposite directions with equal magnitudes. At this case, the resultant vector has zero magnitude but it is still a vector. We call it a null vector.
Materials show varying behaviors based on their Poisson's ratio. High Poisson's ratio materials (near 0.5) contract significantly sideways when stretched and expand when compressed, seen in substances like rubber. Low Poisson's ratio materials (near 0) undergo minimal width change during axial deformation, typical of metals and common engineering materials.