TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: (I) comprises: less than or equal to 2.8 ppm by weight of phosphorus with respect to calcium content, preferably less than or equal to 1.4 ppm by weight of phosphorus with respect to calcium content and/or less than or equal to 0.4 ppm by weight of boron with respect to calcium content; and less than 2.5 wt.%, preferably less than 0.5 wt.% of calcium sulfate. The calcium compound comprises at least 97 wt.% of calcium carbonate and calcium oxide, in the dry state and more than 50 wt.% of calcite. The concentration in carbonate and calcium chloride of the united solution containing carbonate and calcium chloride as well as the temperature at which precipitation is carried out are chosen in such a way as to favor formation of calcite crystals. The solution containing the calcium chloride comprises mother liquor from a soda ash plant that uses the ammonia-soda process. Preferred Process: The first solution containing calcium chloride is added to the second solution containing a carbonate. The process comprises: forming a united solution containing a carbonate and calcium chloride by bringing together carbonate and calcium chloride, either one being provided at least partially in solid form and the other being provided in solution, which solution has a carbonate, respectively calcium, concentration of less than or equal to 0.7 mol/l; precipitating calcium carbonate from a united solution containing a carbonate and calcium chloride by bringing together the carbonate and the calcium chloride, at least one of the carbonate and calcium chloride is provided in an aqueous solution, where prior to the bringing together, boron is removed from the aqueous solution by means of ion exchange resin in such a way that a boron content of below or equal to 1.4 ppm by weight with respect to calcium content is achieved after the bringing together and where the formed united solution containing the carbonate and the calcium chloride has a phosphorus content of below or equal to 4.2 ppm by weight with respect to calcium content; and calcining boron complexes are formed in the aqueous solution by addition of saccharide and/or polysaccharide and/or a surface-active derivative of saccharide and/or polysaccharide, where the formed united solution containing the carbonate and the calcium chloride has a phosphorus content of below or equal to 4.2 ppm by weight with respect to calcium content. In the process: before bringing together the carbonate and the calcium chloride, boron complexes are formed in the aqueous solution by addition of saccharide and/or polysaccharide and/or a surface-active derivative of saccharide and/or polysaccharide; and bringing together includes mixing a first solution comprising the carbonate and a second solution comprising the calcium carbonate. EXAMPLE - Aqueous solution of sodium carbonate was stirred at 50 degrees C in a thermostatised agitated vessel. Aqueous calcium chloride solution was added to the stirred solution at 50 degrees C. The boron contents in the solution amounts 8.4 ppm with respect to calcium content. The addition is done over a period of 45 minutes, followed by additional 15 minutes of stirring. The resulting dispersion was passed over a band filter, the mother liquor was filtered off and the filter cake was washed with deionized water in a countercurrent process step. The wet filter cake was dried in a drying chamber at 105 degrees C to give the calcium product.