Nickel
Nickel (Ni) is a solid silvery white metal (with a melting point of 1494 0C), heavy-duty and plastic. Like pure iron, nickel is easily magnetized. However to confuse it with iron - nickel is so resistant to corrosion that does not tarnish in air, and dissolves very slowly in acids.
A Nickel alloys have unique properties. Known Nickel-titanium alloys are lightweight and durable, used for the manufacture aviatory. Nickel alloy and pure iron is indispensable in microelectronics, and copper-Nickel alloy - Monel is a widely used construction material.
Before the new era of Nickel metal was alloyed with pure copper and got coins and metal utensils.
Nickel compounds in aqueous solution is also nicely colored with salts of Ni2+ have a bright green color. Hydroxide Nickel (II) insoluble in water and has basic properties.
Germanium metal
Germanium metal - is considered rare chemical elements. In the earth's crust it contains about 1,1x10-4%. Germanium was predicted by Mendeleev in the preparation of the table was also described in detail the properties of this metal.
Germanium - white, silvery metal with a metallic luster, but quite fragile. Melts at 958 0C. In chemical compounds can exhibit oxidation states +2 and +4. It should be noted that when the oxidation state is +4 the chemical compounds more stable.
The main use of metal Germany is use is as a semiconductor.
From physics it is known that metals, that are conductors, then temperature is increasing the conductivity decreases, but for semiconductors - increases! At very low temperatures, close to absolute 0 (-273 0C), conductive metals show superconductivity, and semiconductor - become insulators!
Germanium as the pure metal is almost not used, but in an ultra-pure state (without metal impurities with a very high degree of purity) - is widely used in the manufacture of various conduction system. Ultra-pure germanium get with zone melting.