Homoatomare d10‐d10‐Wechselwirkungen — Auswirkungen auf Struktur‐ und Stoffeigenschaften

VII. Square Planar Gold(III) Complexes The archetypal coordination geometry of Auni was established in several early, and necessarily somewhat inaccurate, studies. Thus, KAuBr 4 .2H20 was shown in 1936 to contain square planar AuBr4 ions (98), (n-C3H7)2AuCN to consist of square tetramers with bridging CN groups (99), Et 2AuBr to be dimeric with bridging Br (100) and Me 3PAuBr3 to be monomeric, again with square planar coordination at Au (101). AuX4 and Related Species A large number of AuC14 salts has been studied (Table VIa), although this ion was not always the main object of interest; it often occurs as a stabilizing `large anion'. The Au-Cl distances are rather variable, an average of 24 of the more accurate values reported being 227(1) pm. More examples of AuX4 and related species are given in Table VIb and in Section IX. In all cases the

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X-ray structural investigations of gold compounds: A compilation of reference data. Supplement II

Zintl phases with group 15 elements and the transition metals: A brief overview of pnictides with diverse and complex structures

Experimental and theoretical investigations of the polar intermetallics SrPt 3 Al 2 and Sr 2 Pd 2 Al

The polar intermetallic phases A{sub 2}AuBi (A = Na (I), K (II)), and K{sub 2}AuSb (III) were obtained by direct reaction of the elements at elevated temperatures in niobium ampoules. The three isotypic compounds extend the prominent A{sub 2}MPn (M = transition metal; Pn = group 15) structure family. Single-crystal X-ray diffraction experiments show that these phases (I/II/III) crystallize in the orthorhombic space group Cmcm (No. 63), with a = 9.447(2)/10.632(2)/10.450(2) {angstrom}; b = 7.700(2)/7.918(2)/7.857(2) {angstrom}; c = 5.849(1)/6.597(1)/6.501(1) {angstrom}; V = 425.4(2)/555.4(2)/533.8(2) {angstrom}{sup 3}, respectively, and Z = 4. The simple structures, which contain zigzag chains of linear two-bonded gold atoms and acute angles (64 to 76{sup o}) at two-bonded antimony or bismuth, can readily be rationalized with the Zintl-Klemm concept. TB-LMTO calculations show distinct band gaps at EF, and analyses of DOS and COHP curves show optimized Au-Pn bonding, appreciable Au-Au interactions across the chains, and covalent interactions between A and Pn atoms. The observed structural preference over an isoelectronic NaTl type structure, the cation influences, and site coloring were investigated with VASP and EHTB calculations.

Zigzag Chains of Alternating Atoms in A2AuBi (A = Na, K) and K2AuSb. Synthesis, Structure, and Bonding

Abstract The three new compounds crystallize orthorhombically, space group Cmcm with Na2AuAs: a = 887.1(2) pm, b = 712.9(2) pm, c = 576.0(2) pm; Na2AuSb: a = 927.9(3) pm, b = 756.2(2) pm, c = 584.1(5) pm; K2AuSb: a = 1045.9(5) pm, b = 786.1(3) pm, c = 650.0(5) pm. The structure of Na2AuAs and Na2AuSb contains Au-As(Sb) zigzag chains in which the Au atoms are linearly bonded to the 5b-elements. The powderdiagram shows the phase K2AuSb to be isotypic to Na2AuAs and Na2AuSb.

Na2AuAs, Na2AuSb, K2AuSb - drei neue A2BX-Verbindungen mit B-X-Kettenstruktur / Na2AuAs, Na2AuSb, K2AuSb - Three New A2BX Compounds with a B-X Chain Structure

Abstract Na2AgSb crystallizes orthorhombically, space group Cmcm, with a = 929.2 pm, b = 790.3 pm, c = 577.3 pm. The structure contains Ag-Sb-zigzag-chains with ∢ Ag-Sb-Ag = 180° and ∢ Sb-Ag-Sb = 64.9°.

Cornelia Mues

Papers

Na2AuAs, Na2AuSb, K2AuSb - drei neue A2BX-Verbindungen mit B-X-Kettenstruktur / Na2AuAs, Na2AuSb, K2AuSb - Three New A2BX Compounds with a B-X Chain Structure

Notizen: Darstellung und Kristallstruktur des Na2AgSb / Preparation and Crystal Structure of Na2AgSb