Chromium plating is widely used as decoration plating because it does not corrode in the air and does not lose luster. BACKGROUND ARTĬhromium plating is used for decoration and for industrial use in many industrial fields. The chromium (III) carbonate produced according to the process of the present invention is useful for metal surface treatment such as chromium plating and trivalent chromium chemical conversion treatment. The present invention relates to chromium (III) carbonate and a process for producing the same. Also, preferably, after production of the chromium (III) carbonate, filtration is performed, and the chromium (III) carbonate is washed with water until the conductivity of the filtrate is 5 mS/cm or less. This chromium (III) carbonate is preferably obtained by contacting an aqueous solution of carbonate and an aqueous solution containing trivalent chromium at a pH of 6 to 12 under the condition of a reaction liquid temperature of 0° C. This chromium (III) carbonate is preferably completely dissolved within 30 minutes when the chromium (III) carbonate is added, in an amount corresponding to a Cr content of 1 g, to 1 liter of an aqueous solution of hydrochloric acid having a pH of 0.2 at a temperature of 25° C. This chromium (III) carbonate has an L* value of 50 to 70, an a* value of −4 to −2, and a b* value of −10 to −7, which are represented by the L*a*b* color system (JIS Z8729). The chromium (III) carbonate of the present invention exhibits a light blue color in a solid state.
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