home *** CD-ROM | disk | FTP | other *** search
- Name : Chromium
- Symbol : Cr
- Atomic # : 24
- Atom weight: 51.996
- Melting P. : 1857
- Boiling P. : 2672
- Oxidation : +2, +3, +6
- Pronounced : KROH-mi-em
- From : Greek chroma, "color" - suggest the wide variety of colors
- that characterize chromium compounds.
- Identified : Louis-Nicholas Vauquelin in 1797
- Appearance : Very hard, crystalline, steel-gray metal
- Note : Chromium ore (Siberian red lead) is a popular pigment for
- brilliant red oil paints in the 18th century.
-
- [Properties]
-
- Chromium heads the list of Group VIB elements on the periodic table. It
- shares a number of characteristics, including practical applications, with
- the two preceding metals in the series, vanadium (V) and titanium (Ti).
- Pure chromium metal has a blue-white color. It is hard, brittle, and
- corrosion-resistant at normal environmental temperatures.
- There are two known allotropes of chromium. The most common - the one
- that is stable at room temperature - has a body-centered cubic crystalline
- structure. The second, or beta, form is stable above 1850 degrees. It has
- a close-packed, hexagonal structure.
-