Physical Properties of the Element Chromium

Physical Properties of the Element Chromium Chromium is element atomic number 24 with element symbol Cr. Chromium  Basic Facts Chromium Atomic Number: 24 Chromium Symbol: Cr Chromium Atomic Weight: 51.9961 Chromium Discovery: Louis Vauquelin 1797 (France) Chromium Electron Configuration: [Ar] 4s1 3d5 Chromium Word Origin: Greek chroma: color Chromium Properties: Chromium has a melting point of 1857/-20 °C, a boiling point of 2672 °C, a specific gravity of 7.18 to 7.20 (20 °C), with valences usually 2, 3, or 6. The metal is a lustrous steel-gray color which takes a high polish. It is hard and resistant to corrosion. Chromium has a high melting point, stable crystalline structure, and moderate thermal expansion. All chromium compounds are colored. Chromium compounds are toxic. Uses: Chromium is used to harden steel. It is a component of stainless steel and many other alloys. The metal is commonly used for plating to produce a shiny, hard surface that is resistant to corrosion. Chromium is used as a catalyst. It is added to glass to produce an emerald green color. Chromium compounds are important as pigments, mordants, and oxidizing agents. Sources: The principal ore of chromium is chromite (FeCr2O4). The metal may be produced by reducing its oxide with aluminum. Element Classification: Transition Metal Chromium Physical Data Density (g/cc): 7.18 Melting Point (K): 2130 Boiling Point (K): 2945 Appearance: very hard, crystalline, steel-grayish metal Atomic Radius (pm): 130 Atomic Volume (cc/mol): 7.23 Covalent Radius (pm): 118 Ionic Radius: 52 (6e) 63 (3e) Specific Heat (20 °C J/g mol): 0.488 Fusion Heat (kJ/mol): 21 Evaporation Heat (kJ/mol): 342 Debye Temperature (K): 460.00 Pauling Negativity Number: 1.66 First Ionizing Energy (kJ/mol): 652.4 Oxidation States: 6, 3, 2, 0 Lattice Structure: Body-Centered Cubic Lattice Constant (Ã…): 2.880 CAS Registry Number: 7440-47-3