Chromate
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
|
WikiDoc Resources for Chromate | |
|
Articles | |
|---|---|
|
Most recent articles on Chromate | |
|
Media | |
|
Evidence Based Medicine | |
|
Clinical Trials | |
|
Ongoing Trials on Chromate at Clinical Trials.gov Clinical Trials on Chromate at Google
| |
|
Guidelines / Policies / Govt | |
|
US National Guidelines Clearinghouse on Chromate
| |
|
Books | |
|
News | |
|
Commentary | |
|
Definitions | |
|
Patient Resources / Community | |
|
Directions to Hospitals Treating Chromate Risk calculators and risk factors for Chromate
| |
|
Healthcare Provider Resources | |
|
Causes & Risk Factors for Chromate | |
|
Continuing Medical Education (CME) | |
|
International | |
|
| |
|
Businness | |
|
Experimental / Informatics | |
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
Overview
Chromates and dichromates are salts of chromic acid and dichromic acid, respectively. Chromate salts contain the chromate ion, CrO42−, and have an intense yellow color. Dichromate salts contain the dichromate ion, Cr2O72−, and have an intense orange color.
Characteristics
- The chromium atoms are in oxidation state +6 in both, and the chromate and dichromate ions are fairly strong oxidizing agents. Chromium in the +6 (or VI) oxidation state is often referred to as hexavalent chromium.
- In an aqueous solution, chromate and dichromate anions are in a chemical equilibrium.
- 2 CrO42− + 2 H3O+ ⇌ Cr2O72− + 3 H2O
- This equilibrium can be pushed towards dichromate by lowering the pH (making the solution more acidic) or in the other direction towards chromate by raising the pH to basic. This is a classic example of Le Chatelier's principle at work.
- They are used in environmental analysis to measure chemical oxygen demand (COD).
- They are carcinogenic. All hexavalent chromium compounds are considered toxic and carcinogenic.
- When used as oxidizing agents or titrants in a redox chemical reaction, they will turn into trivalent chromium, Cr3+, which has a distinctively different blue-green color.
- The sodium (Na+), potassium (K+), and ammonium (NH4+) salts are water soluble granular solids and are the most commonly used chromate or dichromate chemical reagents. Most chromate and dichromate salts of heavy metals, lanthanides or alkaline earth metals are only very slightly soluble in water and are thus of much less usefulness.
- Chromate conversion coatings are applied to metals for corrosion protection, and to improve paint adhesion.
- The use of chromate compounds in manufactured goods is restricted in the EU (and by market commonality the rest of the world) by EU Parliament directive 2002/95/EC
Structures
See also
- Potassium dichromate - K2Cr2O7
External links
- IARC Monograph "Chromium and Chromium compounds"
- National Pollutant Inventory - Chromium VI and compounds fact sheet
de:Chromate he:כרומט nl:Chromateren
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
