Title: Sodium Dichromate(VI)
CAS Registry Number: 10588-01-9
Additional Names: Sodium bichromate; bichromate of soda
Molecular Formula: Cr2Na2O7
Molecular Weight: 261.97
Percent Composition: Cr 39.70%, Na 17.55%, O 42.75%
Line Formula: Na2Cr2O7
Literature References: Usually prepd from Na2CrO4 and H2SO4. Description of industrial processes: Müller, Glissmann in Ullmanns Encyklopädie der technischen Chemie vol. 5 (Munich, 3rd ed., 1954) p 575; Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 731-736.
Derivative Type: Dihydrate
Properties: Reddish to bright orange, somewhat deliquescent crystals. Crystal system: monoclinic sphenoidal. Crystal habit: elongated prismatic. d425 2.348. Bulk density: 96 lbs/cu ft. Becomes anhydr on prolonged heating at ~100°. The anhydr salt mp 356.7° and starts to dec at ~400°. Heat of soln -28.2 cal/g. Very sol in water. A satd aq soln contains at 0°: 70.6% Na2Cr2O7.2H2O; at 20°: 73.18%; at 40°: 77.09%; at 60°: 82.04%; at 80°: 88.39%; at 100°: 91.43%. A 20% soln freezes at -3.5°, a 30% soln at -6°, a 60% soln at -26°, a 69% soln at -48°. Specific heat of 20% soln at 25°: 0.85 cal/g/°C. Solns are acidic: pH of 1% soln: 4.0; pH of 10% soln: 3.5.
Melting point: mp 356.7°
Density: d425 2.348; Bulk density: 96 lbs/cu ft
CAUTION: Potential symptoms of overexposure by ingestion are violent gasteroenteritis, peripheral vascular collapse, vertigo, muscle cramps, coma, hemorrhagic diathesis, fever, liver damage and acute renal failure. Direct contact may be highly corrosive to skin and mucous membranes. See Clinical Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins, 5th ed., 1984) Section II, p 108. Chromium hexavalent compounds are listed as known human carcinogens: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-63.
Use: Oxidizing agent in manuf of dyes, many other synthetic organic chemicals, inks, etc.; in chrome-tanning of hides; in electric batteries; bleaching fats, oils, sponges, resins; refining petroleum; manuf chromic acid, other chromates and chrome pigments; in corrosion-inhibitors, corrosion-inhibiting paints; in many metal treatments; electroengraving of copper; mordant in dyeing; for hardening gelatin; for the defoliation of cotton plants and other plants and shrubs, La Lande, US 2760854 (1956 to Pennsylvania Salt).
Therap-Cat: Anti-infective (topical). |