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In this study, we report a scalable magnesio-mechanical reduction method to prepare high quality silicon nanoparticles with good lithium storage performance using low cost starting materials. Although the reaction of Mg and silica is thermodynamically highly favorable, direct reaction using commercial Mg powder by mechanical milling at room temperature is difficult. However, by adding of 5 ​wt % Mg2Si, silica nanoparticles can be reduced into Si nanoparticles using commercial Mg as the reductant by mechanical milling at 250 ​rpm in 5 ​h. Mechanism study suggests that Mg2Si can effectively break the surface oxide layer of Mg due to its high rigidity modules and create fresh Mg surface to initiate the reaction. The obtained Si nanoparticles and Si@C composites exhibit excellent lithium storage performance comparable to that of the state-of-the-art nano-Si anode materials.

The incorporation of unsaturated [Mn(1,2-dap)]2+, [Mn(1,2-dap)2]2+, [Mn(2,2-bipy)]2+ (1,2-dap=1,2-diaminopropane) complex cations with thioarsenate anions of [AsIIIS3]3− and [AsVS4]3− led to three new hybrid manganese thioarsenates, namely, [Mn(1,2-dap)]2MnAs2S6 (1), [Mn(1,2-dap)2]{[Mn(1,2-dap)]2As2S8} (2) and (NH4)[Mn(2,2-bipy)2]AsS4 (3). In compound 1, the unsaturated [Mn(1,2-dap)]2+ complexes, [MnS4]6− tetrahedra and [AsIIIS3]3− trigonal-pyramids are condensed to form the 1D [Mn(1,2-dap)]2MnAs2S6 chain, whereas compound 2 features 2D layer composed of [Mn(1,2-dap)]2+ and [Mn(1,2-dap)2]2+ complexes as well as [AsVS4]3− tetrahedral units. For compound 3, two [AsVS4]3− anions bridge two [Mn(2,2-bipy)]2+ complex cations into a butterfly like {[Mn(2,2-bipy)]2As2S8}2− anionic unit. Magnetic measurements indicate the ferrimagnetic behavior for compound 1 and antiferromagnetic (AF) behaviors for compounds 2–3. The UV–vis diffuse-reflectance measurements and electronic structural calculations based on density functional theory (DFT) revealed the title compounds belong to semiconductors with band gaps of 2.63, 2.21, and 1.97 eV, respectively. The narrow band-gap of compound 3 led to the efficient and stable photocatalytic degradation activity over organic pollutant than N-doped P25 under visible light irradiation.

One new manganese thiogermanate, [(dien) 2 Mn]Ge 2 S 4 (dien=diethylenetriamine), was prepared under mild solvothermal conditions and structurally and spectroscopically characterized. The title compound crystallizes in the orthorhombic system, chiral space group P 2 1 2 1 2 1 (no. 19) with a =9.113(4) A, b =12.475(5) A, c =17.077(7) A, V =1941.5(15) A 3 and Z =4. Its structure features a three-dimensional (3D) network composed of a one-dimensional (1D) [Ge 2 S 4 ] 2− anionic chain and a [(dien) 2 Mn] 2+ complex interconnected via various hydrogen bonds. The most interesting structural feature of the compound is the presence of two different oxidation states of germanium centers in the 1D [Ge 2 S 4 ] 2− chain, which is also supported by the result of X-ray photoelectron spectroscopy measurement. The optical property of the title compound has also been studied by UV–vis spectra.

K 2 Mg 5− x Sn 3 ( x =0.28) and K 3 Mg 18 Tt 11 ( Tt =Sn, Pb) have been synthesized by reacting the mixture of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction studies. K 2 Mg 5− x Sn 3 ( x =0.28) is isostructural with Ni 7− x Sb Q 2 ( Q =Se, Te) series and features 2D corrugated [Mg 5− x Sn 3 ] layers that are separated by K + cations. The structure of K 3 Mg 18 Tt 11 ( Tt =Sn, Pb) is closely related to the Ho 2 Rh 12 As 7 structural type and features 3D [Mg 18 Tt 11 ] framework composed of 1D [Mg 18 Tt 11 ] columns that are interconnected via Mg– Tt bonds, forming 1D hexagonal tunnels occupied by the K+ cations. Electronic structure calculations indicate that Mg atoms can function as either electron donor or as a participator in the network along with Tt atoms. Magnetic property measurements and band structure calculations indicate that these compounds are metallic.

Four new isostructural rare earth manganese stannides, namely RE3MnSn5−x (x=0.16(6), 0.29(1) for RE=Tm, x=0.05(8), 0.21(3) for RE=Lu), have been obtained by reacting the mixture of corresponding pure elements at high temperature. Single-crystal X-ray diffraction studies revealed that they crystallized in the orthorhombic space group Pnma (No. 62) with cell parameters of a=18.384(9)–18.495(6) A, b=6.003(3)–6.062(2) A, c=14.898(8)–14.976(4) A, V=1644.3(14)–1679.0(9) A3 and Z=8. Their structures belong to the Hf3Cr2Si4 type and feature a 3D framework composed of 1D [Mn2Sn7] chains interconnected by [Sn3] double chains via Sn–Sn bonds, forming 1D large channels based on [Mn4Sn16] 20-membered rings along the b-axis, which are occupied by the rare earth atoms. Electronic structure calculations based on density functional theory (DFT) for idealized “RE3MnSn5” model indicate that these compounds are metallic, which are in accordance with the results from temperature-dependent resistivity measurements.

The title compounds have been obtained by solid state reactions of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction studies. Yb 5 Ni 4 Sn 10 adopts the Sc 5 Co 4 Si 10 structure type and crystallizes in the tetragonal space group P 4 /mbm (No. 127) with cell parameters of a =13.785(4) A, c =4.492 (2) A, V=853.7(5) A 3 , and Z =2. Yb 7 Ni 4 Sn 13 is isostructural with Yb 7 Co 4 InGe 12 and crystallizes in the tetragonal space group P 4 /m (No. 83) with cell parameters of a =11.1429(6) A, c =4.5318(4) A, V=562.69(7) A 3 , and Z =1. Both structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are occupied by the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic. These results are in agreement with those from temperature-dependent resistivity and magnetic susceptibility measurements.

Three new ternary potassium(I) zinc(II) or cadmium(II) tellurides, namely, K 2 Cd 2 Te 3 , K 6 CdTe 4 and K 2 ZnTe 2 , were synthesized by solid-state reactions of the mixture of pure elements of K, Cd (or Zn) and Te in Nb tubes at high temperature. K 2 Cd 2 Te 3 belongs to a new structure type and its structure contains a novel two-dimensional [Cd 2 Te 3 ] 2− layers perpendicular to the b -axis. K(5) cation is located at the center of five member rings of the 2D [Cd 2 Te 3 ] 2− layer, whereas other K + cations occupy the interlayer space. K 6 CdTe 4 with a K 6 HgS 4 type structure features a “zero-dimensional” structure composed of isolated CdTe 4 tetrahedra separated by the K + ions. K 2 ZnTe 2 in the K 2 ZnO 2 structural type displays 1D [ZnTe 2 ] 2− anionic chains of edge sharing [ZnTe 4 ] tetrahedra separated by the potassium(I) ions. K 2 Cd 2 Te 3 , K 6 CdTe 4 and K 2 ZnTe 2 revealed a band gap of 1.93, 2.51 and 3.0 eV, respectively.

Two new ternary ytterbium transition metal stannides, namely, Yb3CoSn6 and Yb4Mn2Sn5, have been obtained by solid-state reactions of the corresponding pure elements in welded tantalum tubes at high temperature. Their crystal structures have been established by single-crystal X-ray diffraction studies. Yb3CoSn6 crystallizes in the orthorhombic space group Cmcm (no. 63) with cell parameters of a=4.662(2), b=15.964(6), c=13.140(5) A, V=978.0(6) A3, and Z=4. Its structure features a three-dimensional (3D) open-framework composed of unusual [CoSn3] layers interconnected by zigzag Sn chains, forming large tunnels along the c-axis which are occupied by the ytterbium cations. Yb4Mn2Sn5 is monoclinic space group C2/m (no. 12) with cell parameters of a=16.937(2), b=4.5949(3), c=7.6489(7) A, β=106.176(4)°, V=571.70(8) A3, and Z=2. It belongs to the Mg5Si6 structure type and its anionic substructure is composed of parallel [Mn2Sn2] ladders interconnected by unusual zigzag [Sn3] chains, forming large tunnels along the c-axis, which are filled by the ytterbium cations. Band structure calculations based on density function theory methods were also made for both compounds.

A new rare earth nickel stannide, Sm 2 NiSn 4 , has been prepared by reacting the pure elements at high temperature in welded tantalum tubes. Its crystal structure was established by single crystal X-ray diffraction studies. Sm 2 NiSn 4 crystallizes in the orthorhombic space group Pnma (No. 62) with cell parameters of a =16.878(2) A, b =4.4490(7) A, c =8.915(1) A, and Z =4. Its structure can be viewed as the intermediate type between ZrSi 2 and CeNiSi 2 . Sm 2 NiSn 4 features two-dimensional (2D) corrugated [NiSn 4 ] 6− layers in which the 1D Sn zigzag chains and the 2D Sn square sheets are bridged by Ni atoms. The Sm 3+ cations are located at the interlayer space. Results of both resistivity measurements and extended-Huckel tight-binding band structure calculations indicate that Sm 2 NiSn 4 is metallic.