Two oxygen atoms are not shared, giving an overall stoichiometry of 1:3. Each chromium center therefore shares two oxygen centers with neighbors. The solid consists of chains of tetrahedrally coordinated chromium atoms that share vertices. Production, structure, and basic reactions Ĭhromium trioxide is generated by treating sodium dichromate with sulfuric acid: H 2SO 4 + Na 2Cr 2O 7 → 2 CrO 3 + Na 2SO 4 + H 2OĪpproximately 100,000 tonnes are produced annually by this or similar routes. Chromium trioxide is a powerful oxidiser, a mutagen, and a carcinogen. Millions of kilograms are produced annually, mainly for electroplating. The substance dissolves in water concomitant with hydrolysis. This compound is a dark-purple solid under anhydrous conditions and bright orange when wet. It is the acidic anhydride of chromic acid, and is sometimes marketed under the same name. Unless an exception in 223.7304 applies, or use has been authorized in accordance with 223.7305, use the clause at 252.223-7008, Prohibition of Hexavalent Chromium, in solicitations and contracts, including solicitations and contracts using FAR part 12 procedures for the acquisition of commercial products and commercial services, that are for supplies, maintenance and repair services, or construction.Chromium trioxide (also known as chromium(VI) oxide or chromic anhydride) is an inorganic compound with the formula CrO 3.
Follow the procedures in PGI 223.7305 ( DFARS/PGI view). (b) However, unless an exception in 223.7304 applies, the incorporation of hexavalent chromium in items acquired by DoD shall be specifically authorized at a level no lower than a general or flag officer or a member of the Senior Executive Service from the Program Executive Office or equivalent level, in coordination with the component Corrosion Control and Prevention Executive. (6) Corrosion performance difference of alternative materials or processes as determined by agency corrosion subject matter experts. (5) Materiel availability of hexavalent chromium and the proposed alternatives over the projected life span of the system and (4) Achieving a DoD Manufacturing Readiness Level of at least eight for any qualified alternative (3) Environment, safety, and occupational health risks associated with the use of the hexavalent chromium or substitute materials in each specific application (2) Technical feasibility of alternative materials or processes (1) Cost effectiveness of alternative materials or processes DoD Program Managers must consider the following factors. The DoD policy of April 8, 2009, “Minimizing the Use of Hexavalent Chromium,” contains requirements for weighing hexavalent chromium versus substitutes. (a) The prohibition in 223.7303 does not apply to critical defense applications if no substitute can meet performance requirements. (b) Additional sustainment related contracts (e.g., parts, services) for a system in which use of hexavalent chromium was previously approved. However, alternatives to hexavalent chromium shall be considered by the appropriate official during system modifications, follow-on procurements of legacy systems, or maintenance procedure updates and (a) Legacy systems and their related parts, subsystems, and components that already contain hexavalent chromium. The prohibition in 223.7303 does not apply to. (b) This prohibition is in addition to any imposed by the Clean Air Act regardless of the place of performance. (a) Except as provided in 223.7304 and 223.7305, no contract may include a specification or standard that results in a deliverable or construction material containing more than 0.1 percent hexavalent chromium by weight in any homogeneous material in the deliverable or construction material where proven substitutes are available that provide acceptable performance for the application. Serious human health and environmental risks related to its use. In accordance with the DoD policy memorandum of April 8, 2009, Minimizing the Use of Hexavalent Chromium, it is DoD policy to minimize hexavalent chromium (an anti-corrosive) in items acquired by DoD (deliverables and construction material), due to the “Legacy system,” as used in this subpart, means any program that has passed Milestone A in the defense acquisition management system, as defined in DoD Instruction 5000.02. SUBPART 223.73- MINIMIZING THE USE OF MATERIALS CONTAINING HEXAVALENT CHROMIUM
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