TABLE 21. 6 Oxidation States of Vanadium Oxidation Unused Typical State d-Electrons Examples +5 +4 +3 dddd V2O5, VO4, VO2, 123 Vo2+ 3 +2 2+
Chromium, Cr(the name comes from chroma, greek for color) Bright, lustrous, corrosion-resistant metal FeCr2O4s)+4C(s)△→Fe(s)+2Cr(s)+4CO(g)or Cr2O3(s)+A(s)△→A2O3(s)+2Cr( (thermite铝热 process) Cr metal, mostly, used in steelmaking and for Cr plating CrO2, a ferromagnetic materials used for coating chrome recording tapes because they respond better to high-frequency magnetic fields than do conventional"ferric"(Fe2O3 )tapes chromium(Iv) oxide
Chromium, Cr (the name comes from chroma, Greek for color) Bright, lustrous, corrosion-resistant metal. FeCr2O4 (s) + 4C(s) △→ Fe(s) + 2Cr(s) + 4CO(g) or Cr2O3 (s) + Al(s) △→ Al2O3 (s) + 2Cr(l) (thermite 铝热 process) Cr metal, mostly, used in steelmaking and for Cr plating. CrO2 , a ferromagnetic materials used for coating “chrome” recording tapes because they respond better to high-frequency magnetic fields than do conventional “ferric” (Fe2O3 ) tapes
TABLE 21. 7 Oxidation States of Chromium Oxidation Unused Typical State d-Electrons Examples +6 CrO3, CrO4, Cr20,2 +3 d Cr,Ox Cr3+ +2 d Cr2+
Experiment 21.3 Chromium(VI) Compounds The dish on the left contains a solution of yellow chromate ion, CrO4. When HClaq)Is added to the chromate solu tion in the middle dish we see the formation of orange- red dichromate ion. Cr, 0:. On the right sufficient HCl(aq) has been added to complete the conversion of chromate to dichromate
Cro Cro 2CrO42-(aq)+ 2H(aq)- Cr20,-(ag)+H2oO Cr2O12(aq)+14H(ag)+6e-→2Cr3+(aq)+7H2O(1)E=+1.33V
2CrO4 2- (aq) + 2H+ (aq) → Cr2O7 2- (aq) + H2O(l) Cr2O7 2- (aq)+14H+ (aq)+6e- → 2Cr3+(aq)+7H2O(l) Eo= +1.33V