Element Cobalt, Co, Transition Metal. Have been known for millennia. Glass ingots have been recovered from Egyptian ancientries such as jar dating to the 15. , in coloring of which cobalt salts. Had been used, as well as in the cobalt. Ancient Assyrians and Babylonians used to produce blue paints which were used for ceramics glazing. Contained sapphire was the initial material from which the names of blue paints came.

Element Iridium, Ir, Transition Metal. Syssertskite, platinum, rhodium and ruthenium nevyanskite and aurosmirid. They contain also several other mineral forming elements and belong to the solid solutions class.

Element Iron, Fe Ferrum, Transition Metal. In the heat essentially compounds of the formula Fe. Are formed; in the cold, iron hydroxide, Fe.

Element Nickel, Ni, Transition Metal. Unlike cobalt, which is not employed in the metallic state, metallic nickel is a material which is greatly used. It was formerly used only for alloys; thus German silver is an alloy of nickel with zinc and copper. Some decades ago, however, the difficulties caused by the high temperature of fusion of nickel. The electrical deposition of a metal depends on the fact that at the cathode of a circuit, the cations pass from the state of ions into the neutral state.

Element Palladium, Pd, Transition Metal. Was discovered by William Hyde Wollaston in 1803, also in raw platinum, in the part soluble in aqua regia. When Wollaston separated some quantity of the metal, he, without reporting about the discovery, distributed anonymous advertising about new metal named palladium. This element was named by Wollaston in 1804 after the asteroid Pallas, which was discovered by named by astronomer Heinrich Wilhelm Matthäus Olbers two years earlier.

Element Ruthenium, Ru, Transition Metal. Klaus fused it with saltpeter and isolated the water soluble part. The insoluble part was treated by aqua regia. Then separated the part of crude platinum that was insoluble in aqua regia.

Element Osmium, Os, Transition Metal. About the same time, Collet-Descotils suspected the existence of a new metal by the black powder formed by the dissolution of native platinum in aqua regia. The residue itself named osmiridium.