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A base metal is a common and inexpensive metal, as opposed to a precious metal such as gold or silver. [1] In numismatics , coins often derived their value from the precious metal content; however, base metals have also been used in coins in the past and today.
The oxides of elemental metals are often basic. However, oxides with very high oxidation states such as CrO 3, Mn 2 O 7, and OsO 4 often have strictly acidic reactions; and oxides of the less electropositive metals such as BeO, Al 2 O 3, and PbO, can display both basic and acidic properties. The latter are termed amphoteric oxides.
The chemical elements can be broadly divided into metals, metalloids, and nonmetals according to their shared physical and chemical properties.All elemental metals have a shiny appearance (at least when freshly polished); are good conductors of heat and electricity; form alloys with other metallic elements; and have at least one basic oxide.
Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties.
The alkaline earth metal oxides are formed from the thermal decomposition of the corresponding carbonates. CaCO 3 → CaO + CO 2 (at approx. 900°C) In laboratory, they are obtained from hydroxides: Mg(OH) 2 → MgO + H 2 O. or nitrates: Ca(NO 3) 2 → CaO + 2NO 2 + 1/2O 2. The oxides exhibit basic character: they turn phenolphthalein red and ...
As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium.
A basic oxide, also called a base anhydride (meaning "base without water"), is usually formed in the reaction of oxygen with metals, especially alkali (group 1) and alkaline earth (group 2) metals. Both of these groups form ionic oxides that dissolve in water to form basic solutions of the corresponding metal hydroxide: Alkali metals (Group 1)
The B-subgroup metals can be subdivided into pseudo metals and hybrid metals. The pseudo metals (groups 12 and 13, including boron) are said to behave more like true metals (groups 1 to 11) than non-metals. The hybrid metals As, Sb, Bi, Te, Po, At — which other authors would call metalloids — partake about equally the properties of both.