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The binary phases Ti 5 M 3 , Ti 3 M and Zr 3 M (M = Sn, Sb) were studied for electrochemical lithiation, using powder X-ray diffraction, scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The investigation showed that the morphology of the cathode and the anode surfaces undergo changes, and the grain size of the materials decreases. The phase analysis of the anode materials revealed that the Ti 5 Sn 3 (structure type Mn 5 Si 3 ) and Ti 3 Sn (structure type Mg 3 Cd) phases form solid solutions by insertion of Li atoms into the initial structure. The insertion is reversible. The phases Ti 5 Sb 3 (structure type Y 5 Bi 3 ), Ti 3 Sb, Zr 3 Sn (structure type Cr 3 Si), and Zr 3 Sb (structure type Ni 3 P) form solid solutions by substitution of Li for Sn or Sb atoms. Only the Zr 3 Sb phase showed weakly reversible substitution. Among the investigated compounds, the most suitable structure types for intercalation of lithium appeared to be the Mn 5 Si 3 -and Mg 3 Cd-types, where the Li atoms occupy octahedral voids. The intermetallic compounds containing tin showed better ability for electrochemical lithiation than the compounds containing antimony. This can be explained by the easier interaction of antimony and lithium with the formation of binary compounds. Intermetallic compound / Electrochemical lithiation / Li-ion battery

The structure of lanthanum tetrazinc, LaZn(4), has been determined from single-crystal X-ray diffraction data for the first time, approximately 70 years after its discovery. The compound exhibits a new structure type in the space group Cmcm, with one La atom and two Zn atoms occupying sites with m2m symmetry, and one Zn atom occupying a site with 2.. symmetry. The structure is closely related to the BaAl(4), La(3)Al(11), BaNi(2)Si(2) and CaCu(5) structure types, which can be presented as close-packed arrangements of 18-vertex clusters, in this case LaZn(18). The kindred structure types contain related 18-vertex clusters around atoms of the rare earth or alkaline earth metal.

The new terbium (lithium zinc) distannide, TbLi1–xZnxSn2 (x = 0.2) crystallizes in the ortho­rhom­bic CeNiSi2 structure type with space group Cmcm and Pearson symbol oS16. Of the four independent 4c atom positions (m2m site symmetry), three are fully occupied by individual atoms (two by Sn and one by Tb atoms) and the fourth is occupied by Li and Zn atoms with a statistical distribution. The Tb coordination polyhedron is a 21-vertex pseudo-Frank–Kasper polyhedron. One Sn atom is enclosed in a tricapped trigonal prism, the second Sn atom is in a cubocta­hedron and the statistically distributed (Li,Zn) site is in a tetra­gonal anti­prism with one added atom. Electronic structure calculations were used for the elucidation of reasons for and the ability of mutual substitution of lithium and transition metals. Positive charge density was observed around the rare earth atom and the Li and Zn atoms, the negative charge density in the proximity of the Sn atoms.

Key indicators: single-crystal X-ray study; T = 293 K; mean (La-Zn) = 0.001 Å; R factor = 0.027; wR factor = 0.056; data-to-parameter ratio = 29.9.A single crystal of pentalanthanum dizinc stannide, La 5 Zn 2 Sn, was obtained from the elements in a resistance furnace. It belongs to the Mo 5 SiB 2 structure type, which is a ternary ordered variant of the Cr 5 B 3 structure type. The space is filled by bicapped tetragonal antiprisms from lanthanum atoms around tin atoms sharing their vertices. Zinc atoms fill voids between these bicapped tetragonal antiprisms. All four atoms in the asymmetric unit reside on special positions with the following site symmetries: La1 (..m); La2 (4/m..); Zn (m.2m); Sn (422). Related literature ExperimentalCrystal data The way of bond formation in this compound was assumed using only X-ray diffraction data. Further structure refinement was carried out by means of Jana2006 software package using anharmonic ADP for La1 and Zn atoms.Anharmonic displacement parameters for other atoms were not refined because in case of their refinement their standard deviations were larger than obtained values. As the result we gained lower absolute values of peak and hole in the difference Fourier map (1.02 and -1.17 e Å -3 respectively). The resulting isosurface drawn at the level 0.308 e/Å 3 and sections of difference Fourier map are given in Fig. 2. These maps and sections are noisy but some trends in location of positive and negative regions can be noticed. Positive residual electron density is mostly situated around zinc atoms and near layers made of tin atoms. Negative residual density is mostly located between lanthanum atoms which means that lanthanum atoms donate their electrons to zinc and tin atoms. Similar behaviour of lanthanum atoms can be observed in the LaZn 12.37 compound using electronic structure calculations (See Oshchapovsky et al., (2011)). As a conclusion this compound besides dominate metallic bonding has a weak ionic interaction between lanthanum and zinc and tin atoms. S2. ExperimentalSmall good quality single-crystal of title compound was isolated from alloy with composition La 7 ZnSn 2 during systematic investigation of lanthanum-rich region of La-Zn-Sn ternary system. The samples with high lanthanum contents were prepared by melting of pieces of pure metals in evacuated quartz ampoule with subsequent annealing at