Home Categories Inorganic chemistry Chromium
A2302112

Chromium , 99.95%metalsbasis,1-6mm , 7440-47-3

CAS NO.:7440-47-3

Empirical Formula: Cr

Molecular Weight: 52

MDL number: MFCD00010944

EINECS: 231-157-5

Pack Size Price Stock Quantity
25G RMB199.20 In Stock
100G RMB639.20 In Stock
500G RMB2399.20 In Stock
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Update time: 2022-07-08

PRODUCT Properties

Melting point: 1857 °C (lit.)
Boiling point: 2672 °C (lit.)
Density  7.14 g/mL at 25 °C (lit.)
Flash point: 50 °F
storage temp.  no restrictions.
solubility  reacts with dilute acid solutions
form  powder
color  Silver-gray
Specific Gravity 7.2
PH <1 (H2O, 20°C)
Odor Odorless
Resistivity 12.7 μΩ-cm, 20°C
Water Solubility  Insoluble in water.
Merck  13,2252
Exposure limits TLV-TWA: chromium metal 0.5 mg/m3 (ACGIH and MSHA), 1 mg/m3 (OSHA); Cr(II) and Cr(III) compounds 0.5 mg/m3 (ACGIH); Cr(VI) compounds, water soluble and certain water insoluble, 0.05 mg/m3 (ACGIH).
Stability: Stable. Incompatible with carbonates, strong bases, mineral acids, lithium, sulfur dioxide, strong acids.

Description and Uses

Chromium as a metallic element was first discovered over 200 years ago, in 1797. But the history of chromium really began several decades before this. In 1761, in the Beresof Mines of the Ural Mountains, Johann Gottlob Lehmann obtained samples of an orange-red mineral, which he called ‘Siberian red lead.’ He analyzed this mineral in 1766 and discovered that it contained lead “mineralized with a selenitic spar and iron particles.” The mineral he found was crocoite, a lead chromate (PbCrO4).

The best-known use of chromium is for the plating of metal and plastic parts to producea shiny, reflective finish on automobile trim, household appliances, and other items where abright finish is considered attractive. It also protects iron and steel from corrosion.It is used to make alloys, especially stainless steel for cookware, and items for whichstrength and protection from rusting and high heat are important.Its compounds are used for high-temperature electrical equipment, for tanning leather, asa mordant (fixes the dyes in textiles so that they will not run), and as an antichalking agentfor paints.Some research has shown that, even though most chromium compounds are toxic, a smalltrace of chromium is important for a healthy diet for humans. A deficiency produces diabeteslike symptoms, which can be treated with a diet of whole-grain cereal, liver, and brewer’s yeast.Chromium’s most important radioisotope is chromium-51, which has a half-life of about27 days. It is used as a radioisotope tracer to check the rate of blood flowing in constrictedarteries.Some chromium compounds (e.g., chromium chloride, chromic hydroxide, chromic phosphate) are used as catalysts for organic chemical reactions.In 1960 the first ruby laser was made from a ruby crystal of aluminum oxide (Al2O3). Thesecrystals contain only a small amount of chromium, which stores the energy and is responsiblefor the laser action. A small amount of chromium found in the mineral corundum is responsible for the bright red color of the ruby gemstone.

Safety

Symbol(GHS) 
GHS02,GHS08,GHS09
Signal word  Warning
Hazard statements  H410-H351-H228
Precautionary statements  P201-P202-P280-P308+P313-P405-P501a-P210-P240
Hazard Codes  F,C,Xn,Xi
Risk Statements  11-20/21/22-34-40-23-67-36
Safety Statements  16-26-36/37/39-45-36/37-27
RIDADR  UN 2924 3/PG 2
OEB C
OEL TWA: 0.5 mg/m3
WGK Germany  3
RTECS  GB4200000
Autoignition Temperature 580°C
TSCA  Yes
HS Code  8112 21 90
HazardClass  4.1
PackingGroup  III
Toxicity Elemental chromium and certain chromium compounds have been designated as carcinogens, hazardous substances, hazardous waste constituents, and priority toxic pollutants. Some of those compounds designated as hazardous are chromic acetate, chromic acid, chromic sulfate, and chromous chloride. Although chromium in the 6+ state is regarded as being the most carcinogenic, there are 6+ compounds that appear to be non-carcinogenic. In addition to their possible carcinogenicity, chromium compounds may have local allergic effects leading to dermatitis. Systemically, 6+ chromium compounds are irritants to the respiratory system and may give rise to pulmonary edema.
IDLA 250 mg Cr/m3

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