What kind of isomerism exists between `[Cr(H_(2)O)_(6)]Cl_(3)` (violet) and `[Cr(H_(2)O)_(5)Cl].H_(2)O` (greyish-green)?

What kind of isomerism exists between [Cr(H_(2)O)_(6)]Cl_(3) (violet) and [Cr(H_(2)O)_(5)cl]Cl_(2).H_(2)O (greyish - green)-

What type of isomerism is shown by the pair [Cr(H_(2)O)_(6)]Cl_(3) and [Cr(H_(2)O)_(5)Cl]Cl_(2).H_(2)O ?

[Cr(H_(2)O)_(6)]Cl_(3) & [Cr(H_(2)O)_(5)Cl]Cl_(2).H_(2)O are

The compounds [Cr(H_(2)O)_(6)]Cl_(3) and [Cr(H_(2)O)_(4) Cl_(2)]Cl.2H_(2)O represent