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Sodium dichromate is the inorganic compound with the formula Na 2 Cr 2 O 7.However, the salt is usually handled as its dihydrate Na 2 Cr 2 O 7 ·2H 2 O.Virtually all chromium ore is processed via conversion to sodium dichromate and virtually all compounds and materials based on chromium are prepared from this salt. [1]
For lab and small scale preparations a mixture of chromite ore, sodium hydroxide and sodium nitrate reacting at lower temperatures may be used (even 350 C in the corresponding potassium chromate system). [2] Subsequent to its formation, the chromate salt is converted to sodium dichromate, the precursor to most chromium compounds and materials. [3]
Structure of CrO(O 2) 2 (pyridine).Hydrogen atoms bonded to carbon atoms are omitted. Color code: Cr = gray, C= black, H = white, O= red, N = blue. Chromium(VI) oxide peroxide is formed by the addition of acidified hydrogen peroxide solutions to solutions of metal chromates or dichromates, such as sodium chromate or potassium dichromate.
The chromate and dichromate ions are fairly strong oxidizing agents. Commonly three electrons are added to a chromium atom, reducing it to oxidation state +3. In acid solution the aquated Cr 3+ ion is produced. Cr 2 O 2− 7 + 14 H + + 6 e − → 2 Cr 3+ + 7 H 2 O ε 0 = 1.33 V. In alkaline solution chromium(III) hydroxide is produced.
Chromium trioxide is generated by treating sodium dichromate with sulfuric acid: [6] H 2 SO 4 + Na 2 Cr 2 O 7 → 2 CrO 3 + Na 2 SO 4 + H 2 O. Approximately 100,000 tonnes are produced annually by this or similar routes. [7] The solid consists of chains of tetrahedrally coordinated chromium atoms that share vertices.
The Department of Health and Human Services (HHS) recently released the Scientific Report of the 2025 Dietary Guidelines Advisory Committee.
Sodium nitroprusside – Na 2 [Fe(CN) 5 NO]·2H 2 O; Sodium oxide – Na 2 O; Sodium perborate – NaBO 3 ·H 2 O; Sodium perbromate – NaBrO 4; Sodium percarbonate – 2Na 2 CO 3 ·3H 2 O 2; Sodium perchlorate – NaClO 4; Sodium periodate – NaIO 4; Sodium permanganate – NaMnO 4; Sodium peroxide – Na 2 O 2; Sodium peroxycarbonate – Na ...
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