MANGANESE - CHROME - TUNGSTEN
A chemical element that has the symbol Mn and atomic number 25. It is found as
the free element in nature (often in combination with iron), and in many minerals.
The free element is a metal with important industrial metal alloy uses. Manganese
ions are variously colored, and are used industrially as pigments and as oxidation
chemicals. Manganese (II) ions function as cofactors for a number of enzymes and
the element is thus a required trace mineral for all known living organisms.
A chemical element in the periodic table that has the symbol Cr and atomic number 24.
Chromium is a steel-gray, lustrous, hard metal that takes a high polish and has a
high melting point. It is also odourless, tasteless, and is malleable.
Tungsten, also called Wolfram is a chemical element that has the symbol W
(New Latin: wolframium) and atomic number 74. A very hard, heavy, steel-gray
to white transition metal, tungsten is found in several ores including wolframite
and scheelite and is remarkable for its robust physical properties, especially
the fact that it has the highest melting point of all the non-alloyed metals and
the second highest of all the elements after carbon. The pure form is used
mainly in electrical applications but its many compounds and alloys are widely
used in many applications (most notably in light bulb filaments, and as both the
filament and target in most X-ray tubes and in superalloys).