The multicomponent alumosilicide Li₁₂Mg₃Si₃Al (cubic, space group I3d, cI76) belongs to the structural family based on the Cu₁₅Si₄ type. The Li atoms are ordered and occupy the site with symmetry 1 and the Mg atoms occupy the site with .. symmetry. The Si/Al statistical mixture occupies the site with .3. symmetry. The coordination polyhedra around the Li atoms are 13‐vertex distorted pseudo‐Frank–Kasper polyhedra. The environments of the Mg and Si/Al atoms are icosahedral. The hydrogen storage characteristics of Li₁₂Mg₃Si₃Al were investigated. The reversible hydrogen storage capacity of the title compound is excellent and the gravimetric storage capacity of this new material, corresponding to 9.1 wt% H₂, is higher compared to Li₁₂Mg₃Si₄ (8.8 wt%). The enthalpy of hydrogen desorption is 86 kJ mol⁻¹ and is lower compared to known lithium‐based hydrides.

中文翻译：

---

Li12Mg3Si3Al相的结构和增强的储氢性能

多组分铝硅化物Li ₁₂ Mg ₃ Si ₃ Al（立方，空间群I 3 d，cI 76）属于基于Cu ₁₅ Si ₄类型的结构族。Li原子是有序的并且以对称性1占据位点，而Mg原子则以..对称性占据位点。Si / Al统计混合物占据该位置的0.3。对称。Li原子周围的配位多面体是13个顶点变形的伪Frank-Kasper多面体。Mg和Si / Al原子的环境是二十面体的。Li ₁₂ Mg ₃ Si ₃的储氢特性对铝进行了调查。与Li ₁₂ Mg ₃ Si ₄（8.8 wt％）相比，该标题化合物的可逆储氢容量极好，并且该新材料的重量分析储能（对应于H ₂ 9.1 wt％）更高。氢解吸的焓为86 kJ mol ^-1，与已知的锂基氢化物相比较低。