D-block (for diffuse) elements consist of the transition metals (group 3-12 on the periodic table) in which the outermost electron shell is the D orbital. D-block elements form at least one stable ion with an incompletely filled electron subshell.
... was held by the Japanese until 1875, when they ceded it to Russia. By the Treaty of Portsmouth (U.S.A.) of 1905 the southern part of the island below 50° N was ceded to ...