Name: Chromium Symbol: Cr Atomic Number: 24 Atomic Mass: 51.9961 amu Melting Point: 1857.0 °C (2130.15 K, 3374.6 °F) Boiling Point: 2672.0 °C (2945.15 K, 4841.6 °F) Number of Protons/Electrons: 24 Number of Neutrons: 28 Classification: Transition Metal Crystal Structure: Cubic Density @ 293 K: 7.19 g/cm 3 Color: gray Atomic Structure. Chromium is a chemical element with symbol Cr and atomic number 24. Classified as a transition metal, Chromium is a solid at room temperature.
|Chromium is used extensively in automobile trim as chromium metal because of its shiny finish and corrosion resistance.|
It has an atomic number of 25 and needs 11 more electrons. Tally odbc driver not found. download faster windows 10. So, 10 electrons come from the five CO linked to it while one comes from the Mn-Mn bond. There is no need of bridging. Five Co are linked to one Mn while five are linked to another, while the two Mn are also bonded to each other.
|Atomic Number:||24||Atomic Radius:||189 pm (Van der Waals)|
|Atomic Symbol:||Cr||Melting Point:||1907 °C|
|Atomic Weight:||52.00||Boiling Point:||2671 °C|
|Electron Configuration:||[Ar]3d54s1||Oxidation States:||6, 5, 4, 3, 2, 1, −1, −2, −4 (depending on the oxidation state, an acidic, basic, or amphoteric oxide)|
From the Greek word chroma, color. Chromium is a steel-gray, lustrous, hard metal that takes a high polish. Discovered in 1797 by the Frenchman Louis Nicolas Vauquelin.
The principal ore is chromite, which is found in Zimbabwe, Russia, New Zealand, Turkey, Iran, Albania, Finland, Democratic Republic of Madagascar, and the Phillippines. The metal is usually produced by reducing the oxide with aluminum.
Chromium is used to harden steel, manufacture stainless steel, and form many useful alloys. It is mostly used in plating to produce a hard, beautiful surface and to prevent corrosion. Chromium gives glass an emerald green color and is widely used as a catalyst.
The refractory industry uses chromite for forming bricks and shapes, as it has a high melting point, moderate thermal expansion, and stability of crystalline structure.
All compounds of chromium are colored. The most important chromates are those of sodium and potassium, the dichromates, and the potassium and ammonium chrome alums. The dichromates are used as oxidizing agents in quantitative analysis, also in tanning leather.
Other compounds are of industrial value; lead chromate is chrome yellow, a valued pigment. Chromium compounds are used in the textile industry as mordants, and by the aircraft and other industries for anodizing aluminum.
Chromium compounds are toxic and should be handled with proper safeguards.
Atomic Number Of Carbon Is Equal To
Chromium belongs to the chemical elements belonging to group 6 i.e. transition metals. Molybdenum, Seaborgium, Tungsten are other members of group VI of the periodic table. The periodic table is known because of its arrangement of groups and periods. It also helps in discriminating elements with each other.
Occurrence of Chromium: In the earth’s crust chromium is known to be 22 most existing element. The compounds of chromium are in the environmental form by the erosion of rocks that contain chromium. The mine of chromium is known as Chromite ore i.e. FeCr2O4.
Demographics – Approximately two fifths of the chromite ores are found in South Africa while a third in Kazakhstan. Even Russia, India and Turkey also produce Chromite. There are very less deposits of chromium that is why Russia gives samples of this metal. This mine produced chromium as well as diamond too.
Alloying Behavior of Chromium: Chromium interact with other elements for alloy making and offer excellent corrosion resistance. The group of stainless steel i.e. corrosion resistant steel has the main alloying material chromium in it.
SUS304, UNS S17400, UNS S42000, UNS S30400, UNS S31254, 42CrMo4, UNS S31600 are all different types of steel containing chromium as a main and important alloy.
When the alloying elements are reacting with steels it decompose it into a mixture of ferrite this also leads to the diffusion. Chromium behaves like an alloying element with many metal. Those metals are cobalt, nickel, molybdenum and other.
Physical Properties of Chromium: Due to all the magnetic properties chromium is known because it is an elemental solid but in spite of this it shows anti-ferromagnetic ordering even in room temperatures. When it went above 38 degree centigrade, it becomes paramagnetic i.e. weakly attracted to magnetic field.
Learn about other important chemical elements such as Manganese, Silicon, Carbon which are used together with chromium for alloy making.
When chromium is left in air it makes surface of steel non-reactive by altering the surface of metal through oxidation. This surface is spinel in structure, it is very thick and also prohibits the diffusion of oxygen. The regular state of chromium is solid in real. The melting point is 2180 K while the boiling point is 2944 K.
Advantages of Chromium
Atomic No Of Cr
Due to this ability of chromium, these are used in decoration and coating too. By the way in other words chromium is a brittle, lustrous and hard metal. Chromium is silver gray in color and it is highly polished. It does not lose lustre when it is in free air. When we heat chromium it turns into green chromic oxide. In oxygen chromium is unstable and immediately it gives a thin layer of oxide and also protects the metal.