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Chromium(III) oxide (or chromia) is an inorganic compound with the formula Cr 2 O 3. ... which is reduced with sulfur at high temperatures: [8] Na 2 Cr 2 O 7 + S → ...
Hence, carbon can normally act as a reducing agent for all metal oxides at very high temperatures. But chromium formed at these temperatures reacts with carbon to form its carbide, which gives undesirable properties to the chromium metal obtained. Hence, for high temperature reduction of chromic oxide, carbon cannot be used.
The increased resistance to corrosion found in stainless steel is attributed to a layer of chromium oxide that forms due to oxidation of the chromium found in the alloy. [4] The process of liquid sulfidation has also been used in the manufacturing of diamond-like carbon films. These films are generally used to coat surfaces to reduce the wear ...
A large number of chromium(III) compounds are known, such as chromium(III) nitrate, chromium(III) acetate, and chromium(III) oxide. [8] Chromium(III) can be obtained by dissolving elemental chromium in acids like hydrochloric acid or sulfuric acid, but it can also be formed through the reduction of chromium(VI) by cytochrome c7. [9] The Cr 3+
Clay earth pigments (naturally formed iron oxides) Raw umber (PBr7): a natural clay pigment consisting of iron oxide, manganese oxide and aluminum oxide: Fe 2 O 3 + MnO 2 + n H 2 O + SiO 2 + Al 2 O 3. When calcined (heated) it is referred to as burnt umber and has more intense colors. Raw sienna (PBr7): a naturally occurring yellow-brown ...
Chromium(II) oxide (CrO) is an inorganic compound composed of chromium and oxygen. [1] It is a black powder that crystallises in the rock salt structure. [2] Hypophosphites may reduce chromium(III) oxide to chromium(II) oxide: H 3 PO 2 + 2 Cr 2 O 3 → 4 CrO + H 3 PO 4. It is readily oxidized by the atmosphere. CrO is basic, while CrO 3 is ...
Subsequent to its formation, the chromate salt is converted to sodium dichromate, the precursor to most chromium compounds and materials. [3] The industrial route to chromium(III) oxide involves reduction of sodium chromate with sulfur .
The two principal sulfur oxides are obtained by burning sulfur: S + O 2 → SO 2 (sulfur dioxide) 2 SO 2 + O 2 → 2 SO 3 (sulfur trioxide). Many other sulfur oxides are observed including the sulfur-rich oxides include sulfur monoxide, disulfur monoxide, disulfur dioxides, and higher oxides containing peroxo groups.