Forced hydrolyses of FeCl₃ solutions in the presence of Cr³⁺ ions without alkali addition were investigated at 160 and 200 °C. These precipitation systems were compared to corresponding reference systems. The isolated precipitates were characterized with XRD, ⁵⁷Fe Mössbauer, FT-IR, FE SEM and photocatalytic measurements. Although chromium was not detected by EDS (Energy Dispersive X-ray Spectroscopy), the analysis of samples precipitated in the presence of Cr³⁺ ions showed several effects which can be attributed to the presence of these ions in the starting solutions. These effects are specifically well pronounced for samples obtained at 200 °C. For the highest concentration of Cr³⁺ ions and upon heating at 200 °C the transformation kinetics β-FeOOH to α-Fe₂O₃ was impeded. Relative intensities of prominent diffraction lines 104 and 110 of α-Fe₂O₃ changed as a result of the presence of Cr³⁺ ions. Changes in the size and formation of lemon-like particles instead of cube-like α-Fe₂O₃ particles were also noticed. The presence of Cr³⁺ ions in hydrolysing FeCl₃ solution influenced the photocatalytic degradation of rhodamine B. Since no specific adsorption of Cr³⁺ ions occurred in the acidic pH medium, it was inferred that traces of Cr³⁺ ions enter into the structural tunnels of β-FeOOH crystals. The associates Cl⁻-Cr³⁺ are formed, which in the next step destabilize the crystal structure of β-FeOOH particles. Cr³⁺ ions leave the crystal structure upon dissolution of β-FeOOH. It can be assumed that α-Fe₂O₃ crystals start to grow on very fine and thin β-FeOOH crystallites which were not completely dissolved, but were previously affected by Cr³⁺ ions.

在160和200°C下研究了在不添加碱的情况下在不添加碱的情况下在Cr ³⁺离子存在下的FeCl ₃溶液的强制水解。将这些降水系统与相应的参考系统进行了比较。通过XRD，⁵⁷ FeMössbauer，FT-IR，FE SEM和光催化测量对分离出的沉淀物进行表征。尽管没有通过EDS（能量色散X射线光谱法）检测到铬，但对在Cr ³⁺离子存在下沉淀的样品的分析显示出几种影响，这可以归因于起始溶液中这些离子的存在。对于在200°C下获得的样品，这些效果特别明显。最高浓度的Cr ³⁺离子并且当在200℃的转变动力学β-的FeOOH加热到的α-Fe ₂ ö ₃被阻碍。突出衍射线104和的α-Fe的110的相对强度₂ ö ₃改变Cr的存在的结果³⁺离子。在尺寸和形成改变柠檬样颗粒而不是立方体状的α-Fe _2个ö ₃颗粒也注意到。水解FeCl ₃溶液中Cr ³⁺离子的存在影响了罗丹明B的光催化降解。由于在酸性pH介质中未发生Cr ³⁺离子的特异性吸附，因此可以推断出痕量的Cr ³⁺离子进入β-FeOOH晶体的结构隧道。形成缔合体Cl ^-- Cr ³⁺，其在下一步骤中使β-FeOOH颗粒的晶体结构不稳定。Cr ³⁺离子在β-FeOOH溶解后离开晶体结构。它可以假设的α-Fe ₂ ö ₃晶体开始生长在其上没有完全溶解非常细而薄的β-的FeOOH微晶，但先前由铬影响³⁺离子。