X-ray diffraction analysis of potassium (isothiocyanato)chromate(III) hydrates

K3[Cr(NCS)6] · 3.33H2O (2) and K4[Cr2(OH)2(NCS)8] · 4H2O (3) have been found in a water-alcohol solution when crystalline products of the reaction between KNCS and KCr(SO4)2 · 12H2O were studied by X-ray diffraction. Crystals of complex 2 are trigonal, space group \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P\bar 3m$$\end{document}, Z = 3, a = 14.2296(2) Å, c = 9.6116(3) Å, V = 1685.43(6) Å3, ρcalcd = 1.708 g/cm3. Crystals of complex 3 are triclinic, space group \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P\bar 1$$\end{document}, Z = 2, a = 10.2868(4) Å, b = 12.6344(6) Å, c = 12.6688(6) Å, α = 66.507(4)°, β = 84,713(4)°, γ = 78.234(4)°, V = 1478.21(11) Å3, ρcalcd = 1.867 g/cm3.