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Systematic studies of the phase formation at the binary sections LaSi - LaGa and LaGe - LaAl have been carried out by means of synthetic, crystallographic and bond theoretical methods. The hightemperature forms of the two binary monotetrelides LaSi and LaGe crystallize with the FeB structure type, whereas LaGa forms the related CrB type and LaAl the significantly different CeAl type. Starting from LaSi/LaGe, the FeB type (orthorhombic, space group Pnma, Z = 4, a = 839.2(1)/842.7(1), b = 399.9(1)/412.3(1), c = 606.2(2)/612.2(1) pm, R1 = 0.0356/0.0298) remains stable only down to a valence electron number per M atom (M = Si, Ge, Al, Ga) of 6.9 (LaGa0.10Si0.90: a = 840.14(7), b = 404.12(12), c = 608.5(2) pm, R1 = 0.0513; LaAl0.15Ge0.85: a = 845.40(7), b = 414.08(13), c = 614.08(14) pm, R1 = 0.0213). In the system LaGaxSi1−x, the stability range of the CrB type (orthorhombic, space group Cmcm, Z = 4) starts at a gallium proportion of 25% (LaGa0.25Si0.75: a = 450.03(8), b = 1140.5(2), c = 406.05(6) pm, R1 = 0.0163) and extends to the border compound LaGa (v. e./M = 6). The CrB type also occurs in the system La-Al-Ge, but is in this case only formed around the 1 : 1 composition in between LaAl0.42Ge0.58 (a = 455.90(12), b = 1161.1(3), c = 418.05(9) pm, R1 = 0.0474) and LaAl0.61Ge0.39 (a = 454.89(10), b = 1168.8(2), c = 420.41(11) pm, R1 = 0.0447). These stability ranges, the variations of several key geometric parameters such as the M-M distances or the heights of the trigonal prisms, and the main aspects of the chemical bonding in these lanthanum monometallides are analyzed using FP-LAPWband structure methods. The structure of the new compound La2Al2Ge (V2B3 structure type, orthorhombic, space group Cmcm, a = 416.69(4), b = 2719.7(4), c = 450.46(5) pm, Z = 2, R1 = 0.0458) combines the structural elements of the CrB/FeB structure family (two-bonded M atoms) with the trigonally planar bonded M atoms of the ThSi2 type in a fully ordered Al and Ge atom distribution and thus without phase width

In the course of attempts to substitute Ca by Yb and Sr by Eu in known alkaline earth Al-germanides, the four new ternary compounds Eu3Al1.8Ge2.2, Eu3 Al2Ge4, Yb2 AlGe3, and Yb17Al8Ge19 have been synthesized from mixtures of the elements and their crystal structures determined by means of single-crystal X-ray data. The two europium compounds Eu3Al1.8Ge2.2 (Ta3B4 structure type, orthorhombic, space group Immm, a = 417.68(3), b = 470.70(3), c = 1897.2(2) pm, Z = 2, R1 = 0.0439) and Eu3Al2Ge4 (Sr3Al2Ge4 structure type, monoclinic, space group C2/m, a = 1235.9(6), b = 416.8(2), c = 878.4(4) pm, β = 110.615(13)°, Z = 2, R1 = 0.0978) are isotypic with the corresponding strontium phases. After ionic decomposition, the layers [Al2- Ge4- ]6− in Eu3Al2Ge4 with four-bonded Al and three-bonded Ge atoms can be interpreted as electron-precise Zintl anions. In contrast, the planar ribbons 1∞[Al2/2Ge2Al2/2] of condensed six-membered rings in Eu3Al1.8Ge2.2 exhibit considerably shorter Al-Ge bonds and an Al-Al bond length of only 251 pm. Yb2AlGe3 (orthorhombic, space group Pnma, a = 682.20(10), b = 417.87(9), c = 1813.9(3) pm, Z = 4, R1 = 0.0415) crystallizes with the Y2AlGe3 structure type. Folded [Al2Ge2] ladders, also found in Eu3Al2Ge4 and the known compound Yb7Al5Ge8, are connected by planar cis/trans chains of Ge atoms. The total density of states calculated within the FP-LAPW|DFT band structure approach shows a distinct minimum at the Fermi level for the electron precise Zintl compound Eu3Al2Ge4, whereas π-bonding contributions are evident from the band structures of Eu3Al2Ge2 and Yb2AlGe3. In full accordance, the tDOS of both compounds exhibits no minimum at EF, small phase widths are possible for Eu3Al2Ge2 and related alkaline earth compounds, and Yb2AlGe3 is isotypic with several other more electron-rich LnIII compounds. The complicated structure of the new compound Yb17Al8Ge19 (tetragonal, space group P4/nmm, a = 1542.50(2), c = 788.285(8) pm, Z = 2, R1 = 0.0282) contains three different building blocks: distorted [Al4Ge4] heterocubane units are interconnected by four-bonded Ge atoms to form columns running along the c axis. Secondly, eight-membered rings are formed by alternating Al and Ge atoms, each being in a trigonal-planar Al/Ge coordination. The rings are terminated by Ge atoms (bonded to Ge of the ring) and linked to the first structural unit by a further Ge atom (bonded to Al of the ring). Thirdly, inside the large channels, which are formed by the packing of the eightmembered rings, Ge2 dumbbells are interspersed as a third structural element.

The title compound is synthesized by solid state reaction of a stoichiometric mixture of the elements (573 K for 48 h and 773 K for 72 h). The compound is characterized by single crystal XRD, IR diffuse reflectance spectroscopy, charge transport and magnetic measurements, and TB-LMTO-ASA electronic structure calculations. MnSb 2 Se 4 crystallizes isostructurally with FeSb 2 Se 4 in the monoclinic space group C2/m with Z = 4. The compound is a narrow-bandgap p-type semiconductor and exhibits a large Seebeck coefficient, high electrical resistivity, and low thermal conductivity at 300 K. MnSb 2 Se 4 is paramagnetic at 300 K and undergoes an order/disorder antiferromagnetic transition with a Neel temperature of about 20 K. -(DJIEUTEDJEU, H.; MAKONGO, J. P. A.; ROTARU, A.; PALASYUK, A.; TAKAS, N. J.; ZHOU, X.; RANMOHOTTI, K. G. S.; SPINU, L.; UHER, C.; POUDEU*, P. F. P.; Eur. J. Inorg. Chem. 2011, 26, 3969-3977 57 Fe Moessbauer spectroscopy, single crystal XRD for (III) and (V), and magnetization measurements to study the effects of the number of crystal water molecules on the magnetic behavior. (III) and (V) crystallize in the triclinic space group P1 with Z = 1. All three compounds behave as metamagnets exhibiting very rare field-induced antiferro-ferro-paramagnetic transitions. The number of crystal water molecules has a major effect on the Neel temperature, critical field, and magnetic hardness of the compounds in the ferromagnetic state. The materials behave as molecular magnetic sponges, changing their magnetic properties due to the reversible and controllable dehydration/hydration process. -(HERCHEL*, R.; TUCEK, J.; TRAVNICEK, Z.; PETRIDIS, D.; ZBORIL*, R.; Inorg. Chem. 50 (2011) (1 ≤ n ≤ 5). -The new series of title compounds is prepared by arc melting of stoichiometric mixtures of the elements and characterized by XRD and magnetic measurements. The Ti 2 FeRu 5-n Rh n B 2 (1 ≤ n ≤ 5) compounds crystallize isostructurally in the space group P4/mbm with Z = 2 (Ti 3 Co 5 B 2 -type structure). All the phases order ferromagnetically below Curie temperatures between 220 and 390 K. The series exhibits an evolution from soft to semi-hard magnetic materials with decreasing valence electron count (i.e. decreasing n). -(FOKWA*, B. P. T.; LUEKEN, H.; DRONSKOWSKI, R.; Eur. J. Inorg. Chem. 2011, 26, 3926-3930, http 17 O NMR spectroscopy and ultrahigh-resolution electrospray ionization mass spectrometry to gain insight into the elementary reaction steps involved in the overall water oxidation process. The results are compared with those for an inactive but structurally related Co system, K 6 [Co(H 2 O)SiW 11 O 39 ] (II). It is suggested that the water oxidation capability of (I) is based on its stability at pH > 7 and on the specific binding mode of the water ligand to the Co center in the protected pocket-like active site of (I). -(LIEB, D.; ZAHL, A.; WILSON, E. F.; STREB, C.; NYE, L. C.; MEYER, K.; IVANOVIC-BURMAZOVIC*, I.; Inorg. Chem. 50 (2011) 18, 9053-9058, http Chem. 2011, 26, 4069-4076, http 16 ] with unus...

C h emIn fo rm 2 0 1 2 , 4 3 , issu e 1 0 © 2 0 1 2 Wiley -VCH Verl ag G m b H & Co. K G a A , We i n he i m Struct ure D 2 000 DOI: 1 0.100 2/ch in.201 2100 03 L ant hanum Tr iel/Te tr elide s La(A l,Ga)x(S i , G e) 1-x. Experiment a l and Theo retical Studie s on the Stability of Inte rme tallic 1:1 Phase s. -Phas e f or mation at th e bi nary se ctio ns La Si-La Ga and La Ge -LaA l ar e cha r ac ter ize d by XR D a nd FP-LAPW ele ctronic ban d structure ca lcula tions. The com poun ds are o btain ed from melts of the ele ments . La Si and LaGa 0. 10Si0. 90 c rysta llize in t he o r th orhomb ic spac e g r o up Pnm a with Z =4 (FeB-type struc ture). La Ga0. 25Si0. 75, LaG a 0. 47Si0. 53, LaG a 0. 73Si0. 27, a nd LaGa crystalliz e in the o r th orhomb ic spac e g r o up Cmc m with Z = 4 (Cr B-type str u cture ) . La Ge a n d L a A l 0. 15Ge 0. 85 cr ys talliz e in the orthorhom bic s pa c e group Pnm a w ith Z = 4 ( F eB -t yp e st r u ct u r e ) . L a Al 0. 42Ge 0. 58, L aA l0. 54Ge0. 46, a nd La Al0. 61Ge 0. 39 cr ys talliz e in the orthorhom bic sp ace grou p Cmcm with Z = 4 ( CrB-ty pe struc ture). The ne w com pound La 2Al 2G e c r y sta llize s in the orthorhom bic spa ce group Cmc m with Z = 8 (V2B 3-ty p e s t r u ct u r e ) . T h i s co m p o un d co m b i ne s t h e s t r u ct u r a l el e me n t s o f t h e C r B / F e B st r u c t ur e f a mily ( two-bon ded M atom s) with th e trigon ally plan ar bon ded M atom s of the ThSi2 type with a fully o r d ered Al a nd Ge a tom d istribu tion a nd thu s without pha se width . -( DU E RR , I . ; B AU E R, B. ; R O EH R* , C . ; Z . Na t ur f or sc h. , B : C hem . S ci . 66 ( 201 1) 11, 1 107 -1 121 ; I n st. Anorg . Ana l. Chem ., Alb ert-Ludwigs-Univ., D-791 04 Fr e iburg /B r., Germa ny; Ger., Abstr. Eng .) -W. Pe we sto r f 10 -00 3