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CrO 2 was first prepared by Friedrich Wöhler by decomposition of chromyl chloride. Acicular chromium dioxide was first synthesized in 1956 by Norman L. Cox, a chemist at E.I. DuPont, by decomposing chromium trioxide in the presence of water at a temperature of 800 K (527 °C; 980 °F) and a pressure of 200 MPa.
Each string oxidation-state-number values an oxidation-state-number eg "+3," starts with a space or a newline, followed by; a math minus sign (not a dash) OR; a plus OR; nothing; followed by number, followed by comma (every entry including the last one), a referenced-oxidation-state-number is an oxidation-state-number followed by a <ref ...
Chromium compounds are compounds containing the element chromium (Cr). Chromium is a member of group 6 of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist. [3] [4]
See also: oxidation states in {{infobox element}} [ edit ] The oxidation states are also maintained in articles of the elements (of course), and systematically in the table {{ Infobox element/symbol-to-oxidation-state }}
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
See also: oxidation states in {{infobox element}} [ edit ] The oxidation states are also maintained in articles of the elements (of course), and systematically in the table {{ Infobox element/symbol-to-oxidation-state }}
In ionic compounds, the oxidation numbers are the same as the element's ionic charge. Thus for KCl, potassium is assigned +1 and chlorine is assigned -1. [4] The complete set of rules for assigning oxidation numbers are discussed in the following sections. Oxidation numbers are fundamental to the chemical nomenclature of ionic
The name of the element is derived from the Greek word χρῶμα, chrōma, meaning color, [12] because many chromium compounds are intensely colored. Industrial production of chromium proceeds from chromite ore (mostly FeCr 2 O 4) to produce ferrochromium, an iron-chromium alloy, by means of aluminothermic or silicothermic reactions ...