Reactions of Ag2O and TeO2 at elevated oxygen pressures resulted in three new silver oxotellurates: Ag2Te4O11 (PI, a 7,287(4), b = 7,388(3), c = 9,686(7) angstrom, alpha = 95,67(3)degrees, beta = 94,10(3)degrees, gamma = 119,40(3)degrees, Z = 2, 1973 independent reflections, R, = 2,51 %, wR(2) 5,42 %) and two modifications of AgTeO3 (AgTeO3-I: P2(1)/n, a = 5,9099(5), b = 11,6831(8), c = 8,0305(7) angstrom, beta = 100,424(7)degrees, Z = 4, 1249 independent reflections, R-1 = 7,72 %, wR(2) = 13,24%; AgTeO3-II: P2(1)/m, a = 5 4562(5), b = 7,4009(7), c = 6,9122(7) angstrom, beta = 101,237(2)degrees, Z = 2, 1221 independent reflections, R-1 = 2,84%, wR(2) = 6,16 %). All the three compounds contain tellurium in the oxidation states +4 and +6. Te6+ is coordinated by distorted octahedra of oxygen atoms in each case, while the lone pair of Te4+ is stereochemically active, and the coordination numbers are 5 in Ag2Te4O11 and AgTeO3-II (distorted square pyramids, pseudo octahedra) and 4 in AgTeO3-I (pseudo trigonal bipyramid). All compounds show diamagnetic and insulating behaviour.

La-5(C-2)Ge-2 was obtained as a minor component from the reaction of the elements in corundum crucibles enclosed in stainless steel ampoules at 1360 K. The compound is gray with metallic luster. The crystal structure of La-5(C-2)Ge-2 (space group Pbam, a = 8.873 Angstrom, b = 12.946 Angstrom, c = 4.273 Angstrom; Z = 2; R-gt(F) = 0.069, R-W(F-2) = 0.147) is an arrangement of condensed La-9 3-fold capped trigonal prisms and La-6 octahedra, centered by Ge atoms and C-2 dumbbells, respectively (d(Ge-La) = 3.173 - 3.887 Angstrom; d(C-La) = 2.42 Angstrom (end-on) and 2.83 Angstrom. (side-on); d(C-C) = 1.34 Angstrom). The structure differs from the La2SnS5 structure with covalent Sn-S bonds only by the replacement of the Sn atoms by C-2 dumbbells: La2SnS5 = S-5(Sn)La-2 = La-5(C-2)Ge-2. The anionic chains of edge-condensed octahedra (1)(infinity)[SnS4/2S2](4-) are replaced by (1)(infinity)[(C-2)La4/2La2] chains, containing remarkable piles of alternating C-2 and La-2 pairs (d(La-La) = 3.438 Angstrom) with side-on coordination along the c axis. The formal oxidation states La3+, Ge4-, C-2(4-) yield in an excess of three electrons per formula unit. The source of rest electron density of about 2.5 e(.)Angstrom(-3) is analyzed and discussed. The calculated band structure indicates metallic behavior.

Pb2(Hg3O4)(CrO4) consists of [CrO4]2- tetrahedra, linear O-Hg-O dumbbells and divalent Pb atoms in [3+5]-coordination. The HgO2 dumbbells are condensed into [Hg3O4]2- units and can be regarded as a section of the HgO structure. The [Hg3O4]2- complex anions are connected by interstitial Pb2+ ions, while the [CrO4]2- tetrahedra are isolated.

Ag2TeO4 was synthesised by reaction of Ag2O and TeO2 applying an elevated oxygen pressure. According to a single crystal structure determination (C2/c, a = 9.0588(9), b = 9.2456(8), e = 13.623(1) angstrom, beta = 91.758(8)degrees, Z = 12, 1289 independent reflections, R1 = 2.32%, wR2 = 5.51%), Ag2TeO4 contains a novel chain-like polyanion with tellurium in an octahedral coordination. The TeO6 octahedra are connected via common edges and vertices in a way that the resulting polyanion represents a section of the rutile structure type. Ag2TeO4 shows diamagnetic and insulating behaviour, it decomposes at 560 degrees C into Ag2TeO3 and oxygen.

AgAsO3 was prepared, for the first time, through solid state reaction of Ag2O and As2O3, or As, respectively, while applying an elevated oxygen pressure (T = 500 degreesC, p(O-2) = 2 kbar, 1-2 days). The crystal structure (Pca2(1); a = 1948.8(3), b = 660.0(1), c = 1266.1(3) pm; Z = 24; 4741 independent reflexions; R-1 = 0.044) contains a novel polyanion, (1)(infinity)[(AsO6/2)(AsO2/1O2/2)(2)], with arsenic in an octahedral and tetrahedral coordination, at the same time. It thus features structural units similar to those in binary As2O5.

Ag2AsKO4, tetragonal, 1 (4) over tilde 2m (no. 121), a = 5.9033(8) A, c = 7.082(1) A, V = 246.8 A(3), Z = 2, R-gt(F) = 0.030, wR(ref)(F-2) = 0.068, T = 293 K.

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The structure of Pb(2)HgCrO(6) (space group P-1) can be described as consisting of isolated [CrO(4)](2-) tetrahedra and nearly linear [HgO(2)](2-) dumb-bells, which form layers of composition [HgCrO(6)](4-). These are intercalated with corrugated pseudo-hexagonal Pb(2+) layers. The Pb(2+) cation is stereochemically active and has coordination 3+5.

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AgCuO2 has been obtained via a low temperature route. The structure has been redetermined with Rietveld refinements using neutron powder diffraction data [C2/m, a=6.0756(3), b=2.8088(1), c=5.8728(3) Å, β=107.987(4)°, Z=2, Rp=6.36%, Rwp=7.22%]. The crystal structure consists of chains of ladder-like CuO4-rectangles running along [010], interconnected by AgO2-dumbbells. For physical and crystal chemical reasons the oxidation states +I for silver, and +III for copper, respectively, have been assigned. High-pressure X-ray powder diffraction experiments have been made. AgCuO2 is stable with respect to decomposition and structural distortion up to 36.3 GPa. The zero pressure bulk modulus of AgCuO2 is estimated as 118.2 GPa.

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The new silver cuprate AgCuO2 was synthesized by applying a low-temperature route. AgCuO2 precipitates as a microcrystalline black and thermally labile powder from concentrated aqueous solutions of copper and silver nitrate under alkaline and oxidizing conditions. Using the positional parameters of AgAgO2 as a starting set, Rietveld refinements have been performed using X-ray and neutron powder data (P21/c, a=5.8657(3), b=2.8062(2), and c=6.0770(3) Å, β=108.106(4)°, Z=2, Rp=6.61%, Rwp=5.00% for joint refinement). The crystal structure consists of chains of ladder-like CuO4 rectangles running along [010], interconnected by AgO2 dumbbells. For physical and crystal chemical reasons the oxidation states +I for silver and +III for copper, respectively, have been assigned. Similar to AgAgO2 and CuO the metal cations form a fcc structure with oxygen at positions slightly displaced from the centers of the octahedral vacancies. The small differences from the AgAgO2 structure can be traced back to a different off-center position in the octahedral void.

Single crystals of Ag2Cu2O3 were prepared by solid state reaction of Ag2O and CuO applying an oxygen pressure of 200 MPa. Crystals of Ag2Cu2O3 (I41/amd, a=589.78(6), c=1071.4(2) pm from single crystal data, Z=4, 289 unique diffractometer data, R1=0.043, wR2=0.098) are black and stable in air and moisture. The refinement of the crystal structure confirms previous results as obtained from powder data; however, the process has lead to improved precision. Electrochemical deintercalation experiments have been performed. From electrotitration curves and structural investigations on the resulting deintercalated phases we have been able to deduce an irreversible “single phase mode” deintercalation mechanism.

Ba4Ge25Na2, cubic, P4(1)32 (No, 213), a =14.4703(2) Angstrom, V = 3029.9 Angstrom (3), Z = 4, R-gt(F) = 0.052, wR(ref)(F-2) = 0.108, T = 293 K.

Ag3ClCrO4, tetragonal, P4/nmm (No. 129), a = 7.3889(5) Angstrom, c = 5.3065(3) Angstrom, V = 289.7 Angstrom (3), Z = 2, R-gt(F) = 0.042, wR(ret)(F-2) = 0.097. T = 293 K.

The isotypic compounds LiM4[BN2](3) (M = Ca, Sr, Ba, Eu) and NaM4[BN2](3) (M = Sr, Ba) are formed as colorless to pale yellow prismatic crystals (black with Eu) by reaction of the binary components Li3N, M3N2, EuN and Na, NaN3, Ba3N2 and BN in sealed niobium ampoules at 1375 and 1275 K, respectively. The linear anions [N-B-N](3-) have bond lengths d(B-N) between 132.6 and 136.6 pm. Vibrational frequencies and force constants f(B-N) = 7.25-7.89 Ncm(-1) reveal significant drifts related to bond length and effective anionic charge. The cubic crystal structures (Im (3) over bar m (No.229), Z = 2; LiM4[BN2](3): a(Ca) = 711.5 pm; a(Sr) = 745.6 pm; a(Eu) = 742.5 pm, a(Ba) = 788.0 pm and NaM4[BN2](3): a(Sr) = 756.8 pm; a(Ba) = 791.7 pm)) are stuffed derivatives of the beta-PtHg4 structure type, and the range of existence of this cubic structure is derived from the molar volume and the ionic radii. The cations form a partial structure of centered cubes E1(E2)(8) which are condensed to a (3)(infinity)[E1(E2)(8/2)] network (E1 = Li, Na; E2 = Ca, Sr, Ba, Eu). The remaining open cubes are filled by the [BN2](3-) anions yielding two interpenetrating (3)(infinity)[E1(BN2)(6/2)] networks. Periodic Nodal Surfaces (PNS) of Im (3) over bar m symmetry show the regions of different interactions.

The silver mercurate Ag2HgO2 is accessible by oxygen high pressure synthesis; the compound crystallizes in a novel structure type with three interpenetrating Ag–O–Hg (10, 3) nets.

Abstract La4(C2)2Ge was obtained as a minor component from the reaction of the elements in corundum crucibles enclosed in stainless steel ampoules at 1360 K. The compound is gray with metallic luster. The crystal structure (space group I 4 3d (No. 220); a=8.995(1) A; Z=4; R(F)=0.033, Rw(F2)=0.061 for 106 reflections (all data) with 2θmax=50° measured on four-circle diffractometer) may be described as a 3D framework of condensed La8 dodecahedra (bisdisphenoids) centered by Ge atoms and C2 dumbbells (d(C–C)=1.22 A). La4(C2)2Ge and the previous reported cubic compounds La2C3≙La4(C2)3, “La5C1.5Ge3” ≙La4(C2)0.60Ge2.40, and La4Ge3 demonstrate the existence of a large range of homogeneity La4[(C2)1−xGex]3 between the yellow transparent ethenide (4-) La2C3 and La4Ge3. In the series, the C2 dumbbells are replaced by Ge atoms, corresponding with the formal charges C4−2, Ge4−, and La3+. These mixed crystals (Pearson symbol cI28⇔40) represent a continuous transition between the structure types cI40 (Rb4O6/Pu2C3) and cI28 (Th3P4). The results are discussed together with the general trends in the members of both structures types.