In this paper we report an investigation into the phases formed on dehydration of Na₂M(SO₄)_2−x(SeO₄)_x·2H₂O (0 ≤ x ≤ 1; M = Mn, Fe, Co and Ni). For the Fe series, all attempts to dehydrate the samples doped with selenate resulted in amorphous products, and it is suspected that a side redox reaction involving the Fe and selenate may be occurring leading to phase decomposition and hence the lack of a crystalline product on dehydration. For M = Mn, Co, Ni, the structure observed was shown to depend upon the transition metal cation and level of selenate doping. An alluaudite phase, Na₃M_1.5(SO₄)_3-1.5x(SeO₄)_1.5x, was observed for the selenate doped compositions, with this phase forming as a single phase for x ≥ 0.5 M = Co, and x = 1.0 M = Ni. For M = Mn, the alluaudite structure is obtained across the series, albeit with small impurities for lower selenate content samples. Although the alluaudite-type phases Na_2+2y(Mn/Co)_2−y(SO₄)₃ have recently been reported [1,2], doping with selenate appears to increase the maximum sodium content within the structure. Moreover, the selenate doped Ni based samples reported here are the first examples of a Ni sulfate/selenate containing system exhibiting the alluaudite structure.

在本文中，我们报告了对Na ₂ M（SO ₄）_2-x（SeO ₄）_x ·2H ₂ O（0≤x≤1; M = Mn，Fe，Co和Ni）脱水形成的相的研究。 。对于Fe系列，所有试图使掺有硒酸盐的样品脱水的尝试都会产生无定形产物，并且怀疑可能发生涉及Fe和硒酸盐的副氧化还原反应，从而导致相分解，因此在脱水时缺乏结晶产物。 。对于M ＝ Mn，Co，Ni，显示观察到的结构取决于过渡金属阳离子和硒酸盐掺杂的水平。铝辉石相，Na ₃ M _1.5（SO ₄）对于硒酸盐掺杂的组合物观察到_3-1.5x（SeO ₄）_1.5x，对于_x≥0.5  M = Co，x = 1.0  M = Ni ，该_相形成为单相。对于M = Mn，在整个系列中均获得了钙铝石结构，尽管对于硒含量较低的样品来说杂质很小。尽管最近有报道称别称钙钛矿型相Na _{2 + 2y}（Mn / Co）_{2 -y}（SO ₄）₃ [1,2]，硒酸盐的掺杂似乎会增加结构中的最大钠含量。而且，这里报道的硒酸盐掺杂的镍基样品是表现出钙铝石结构的硫酸镍/含硒酸盐的体系的第一个实例。