Structure and thermolysis of NiC₂O₄·2H₂O (I) and Ni(HCO₂)₂·2H₂O (II) were studied for the precipitated powders from the water solutions of precursors. The compound (I) has a disordered structure (C2/c, a=11.7916(5), b=5.31798(14), c=9.7806(7) Å, β=127.014(6)°, V=489.73(4)ų) which is described via the displacement vector applied to the basis atoms and the part of the shifted atoms. Thermal dehydration of (I) leads to formation of the disordered β-NiC₂O₄ (III), the structure of which (P2₁/n, a=5.8294(9), b=5.1685(13), c=5.2712(4) Å, β=117.793(12)°, V=140.50(5)ų) was refined from the powder diffraction. Oxalates (I) and (III) are both characterized by the essential part of the shifted atoms causing the extinction of some lines in XRPD pattern. The final product of thermal decomposition of (I) in air is NiO, whereas thermolysis of (II) leads to formation of Ni/NiO mixture. The content of Ni in the latter depends on the thickness of the decaying layer in the sample because the gaseous products of the reaction prevent the oxidation of the nickel formed initially.

研究了NiC ₂ O ₄ ·2H ₂ O（I）和Ni（HCO ₂）₂ ·2H ₂ O（II）的结构和热解过程，以分析前驱体水溶液中的沉淀粉末。化合物（I）具有无序结构（C 2 / c，a = 11.7916（5），b = 5.31798（14），c = 9.7806（7）Å，β= 127.014（6）°，V = 489.73（4 ）埃³被描述）通过位移矢量施加到基础原子和的部分移位原子。（I的热脱水）导致形成无序β-NIC的₂ ö ₄（III），其结构（的P 2 ₁ / Ñ，一个= 5.8294（9），b = 5.1685（13），C ^ = 5.2712（4），由粉末衍射精制β＝ 117.793（12）°，V ＝ 140.50（5）³）。草酸盐（I）和（III）的特征均在于转移原子的基本部分，导致XRPD图样中的某些线消失。（I）在空气中热分解的最终产物是NiO，而（II）的热分解）导致形成Ni / NiO混合物。后者中的镍含量取决于样品中衰减层的厚度，因为反应的气态产物阻止了最初形成的镍的氧化。