The trans-Aquahydroxo-di-μ-hydroxo-bisfac-triamminechromium(III) ion, trans-(H₂O)(NH₃)₃Cr(OH)₂Cr(NH₃)₃(OH)³⁺, formed by condensation of fac-triamminetriaquachromium(III) ions with base : preparation, characterization and X-ray structure analysis (engelsk)