Strong Attraction of Caffeine to the Mercurous Dumbbell in the Salt [Hg2(Caf)2](ClO4)2(H2O)2

Colourless single crystals of the caffeine adduct of mercurous perchlorate dihydrate, [Hg₂(Caf)₂](ClO₄)₂(H₂O)₂, were grown from aqueous solutions of mercurous perchlorate and caffeine by isothermal evaporation at ambient temperature. The crystal structure (monoclinic, P2₁/n, Z = 4, a = 1628.0(2), b = 780.4(1), c = 2229.6(3) pm, β = 99.84(1)°, R₁(all data) = 0.0894) contains [trans‐Caf‐Hg‐Hg‐Caf]²⁺ cations with a Hg‐Hg distance of 250.88(6) pm, Hg‐N (bond) distances of 214.4(6) and 215.1(6) pm and Hg‐Hg‐N angles of 176.9(2) and 165.1(2)°, respectively. These cations are attached via weak Hg‐O contacts to dimers which are further arranged to leave large channels into which one crystal water molecule is included. The second water molecule and the two perchlorate anions are weakly attracted to one Hg atom.     

Crystal Structures and Raman Spectra of cis‐[SnCl4(H2O)2]·2H2O,cis‐[SnCl4(H2O)2]·3H2O, [Sn2Cl6(OH)2(H2O)2]·4H2O,and [HL][SnCl5(H2O)]·2.5H2O (L=3‐acetyl‐5‐benzyl‐1‐phenyl‐4, 5‐dihydro‐1, 2, 4‐triazine‐6‐one oxime,C18H18N4O2)

The complexes cis‐[SnCl₄(H₂O)₂]·2H₂O ( 1 ), [Sn₂Cl₆(OH)₂(H₂O)₂]·4H₂O ( 3 ), and [HL][SnCl₅(H₂O)]·2.5H₂O ( 4 ) were isolated from a CH₂Cl₂ solution of equimolar amounts of SnCl₄ and the ligand L (L=3‐acetyl‐5‐benzyl‐1‐phenyl‐4, 5‐dihydro‐1, 2, 4‐triazine‐6‐one oxime, C₁₈H₁₈N₄O₂) in the presence of moisture. 1 crystallizes in the monoclinic space group Cc with a = 2402.5(1) pm, b = 672.80(4) pm, c = 1162.93(6) pm, β = 93.787(6)° and Z = 8. 4 was found to crystallize monoclinic in the space group P2₁, with lattice parameters a = 967.38(5) pm, b = 1101.03(6) pm, c = 1258.11(6) pm, β = 98.826(6)° and Z = 2. The cell data for the reinvestigated structures are: [SnCl₄(H₂O)₂]·3H₂O ( 2 ): a = 1227.0(2) pm, b = 994.8(1) pm, c = 864.0(1) pm, β = 103.86(1)°, with space group C2/c and Z = 4; 3 : a = 961.54(16) pm, b = 646.29(7) pm, c = 1248.25(20) pm, β = 92.75(1)°, space group P2₁/c and Z = 4.     

Polysulfonylamine. XXXVII. Darstellung von Quecksilberdimesylamiden. Kristall- und Molekülstrukturen von Hg[N(SO2CH3)2]2, Hg[{N(SO2CH3)2}2(DMSO)2] und Hg[{N(SO2CH3)2}2(HMPA)]

Polysulfonyl Amines. XXXVII. Preparation of Mercury Dimesylamides. Crystal and Molecular Structures of Hg[N(SO₂CH₃)₂]₂, Hg[{N(SO₂CH₃)₂}₂(DMSO)₂], and Hg[{N(SO₂CH₃)₂}₂(HMPA)] Hg[N(SO₂CH₃)₂]₂ ( 1 ) and Hg₂[N(SO₂CH₃)₂]₂ ( 2 a ) are formed as colourless, sparingly soluble precipitates when solutions of Hg(NO₃)₂ or Hg₂(NO₃)₂ in dilute nitric acid are added to an aqueous HN(SO₂CH₃)₂ solution. By a similar reaction, Hg₂[N(SO₂C₆H₄ ? Cl? 4)₂]₂ is obtained. 1 forms isolable complexes of composition Hg[N(SO₂CH₃)₂]₂ · 2 L with L = dimethyl sulfoxide (complex 3 a ), acetonitrile, dimethyl formamide, pyridine or 1,10-phenanthroline and a (1/1) complex Hg[N(SO₂CH₃)₂]₂ · HMPA ( 4 ) with hexamethyl phosphoramide. Attempted complexation of 2 a with some of these ligands induced formation of Hg⁰ and the corresponding Hg^II complexes. Crystallographic data (at -95°C) are for 1: space group 14₁/a, a = 990.7(2), c = 2897.7(8) pm, V = 2.844 nm³, Z = 8, D_x = 2.545Mgm^?3; for 4a: space group P1 , a = 767.8(2), b = 859.2(2), c = 925.2(2)pm α = 68.44(2), β = 86.68(2), γ = 76.24(2)°, V = 0.551nm³, Z = 1, D_x = 2.113 Mgm^?3; for 4: space group P2₁/c, a = 1041.3(3), b = 1545.4(3), c = 1542.5(3) pm, β = 100.30(2)°, V = 2.474nm³, Z = 4, D_x = 1.944Mgm³. The three compounds form molecular crystals. The molecular structures contain a linear or approximately linear, covalent NHgN moiety; the Hg? N distances and N? Hg? N angles are 206.7(4) pm and 176.3(2)° for 1, 207.2(2) pm and 180.0° for 3a, 205.7(4)/206.7(4) pm and 170.5(1)° for 4. In the complexes 3a and 4, the 0-ligands are bonded to the Hg atoms perpendicularly to the N? Hg? N axes, leading in 3a to a square-planar trans-(N₂O₂) coordination with Hg? 0 261.2(2) pm and N? Hg? O 92.3(1)/87.7(1)°, in 4 to a slightly distorted T-shaped (N₂O) geometry with Hg? 0 246.2(4)pm and N? Hg? 0 96.7(1)/92.0(1)°. In all three structures, the primary coordination is extended to a severely distorted (N₂O₄) hexacoordination by the appropriate number of secondary, inter- and/or intramolecular Hg…?0 inter-actions (0 atoms from sulfonyl groups, Hg…?O distances in the range 280—300pm). The intramolecular Hg…?O interactions give rise to nearly planar four-membered [HgNSO] rings. The molecule of 1 has a two-fold axis through the bisector of the N? Hg? N angle, the molecule of 3a an inversion center at the Hg atom. The molecule of 4 has no symmetry.     

The Monohydrate of Basic Mercuric Nitrate, [Hg(OH)](NO3)(H2O)

Colourless single crystals of [Hg(OH)](NO₃)(H₂O) were obtained by slow evaporation of an aqueous solution of Hg(NO₃)₂ and Bi(NO₃)₃. The crystal structure (orthorhombic, Pbca, Z = 8, a = 943.2(2), b = 697.6(1), c = 1349.0(2) pm, R₁(all) = 0.0780) contains [Hg(OH)] = …OH–Hg–OH–Hg… zig zag chains (O–Hg–O angle: 168°, Hg–O–Hg angle: 112°, Hg–OH distance: 212 pm) to which one water molecule is attached loosely. The [Hg(OH)](H₂O) chains are connected via bis‐monodentate‐bridging nitrate ions to corrugated layers that are stacked in the [001] direction. Hg²⁺ has an effective 2+2+2(+1) coordination.     

M(H2O)2(4,4′‐bipy)[C6H4(COO)2]·2H2O (M = Mn2+, Co2+) – Zwei isotype Koordinationspolymere mit Schichtstruktur

M(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O (M = Mn²⁺, Co²⁺) – Two Isotypic Coordination Polymers with Layered Structure Monoclinic single crystals of Mn(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O ( 1 ) and Co(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]· 2H₂O ( 2 ) have been prepared in aqueous solution at 80 °C. Space group P2/n (no. 13), Z = 2; 1 : a = 769.20(10), b = 1158.80(10), c = 1075.00(10) pm, β = 92.67(2)°, V = 0.9572(2) nm³; 2 : a = 761.18(9), b = 1135.69(9), c = 1080.89(9) pm, β = 92.276(7)°, V = 0.9337(2) nm³. M²⁺ (M = Mn, Co), which is situated on a twofold crystallographic axis, is coordinated in a moderately distorted octahedral fashion by two water molecules, two oxygen atoms of the phthalate anions and two nitrogen atoms of 4,4′‐biypyridine ( 1 : M–O 219.5(2), 220.1(2) pm, M–N 225.3(2), 227.2(2) pm; 2 : Co–O 212.7(2), 213.7(2) pm, Co–N 213.5(3), 214.9(3) pm). M²⁺ and [C₆H₄(COO)₂)]^2? build up chains, which are linked by 4,4′‐biyridine molecules to yield a two‐dimensional coordination polymer with layers parallel to (001).Thermogravimetric analysis in air of 1 indicated a loss of water of crystallization between 154 and 212 °C and in 2 between 169 and 222 °C.     

Darstellung von Organylquecksilber(II)‐di(methansulfonyl)amiden und Kristallstruktur von Ph–Hg–N(SO2Me)2

Polysulfonylamines. CXXIV. Preparation of Organylmercury(II) Di(methanesulfonyl)amides and Crystal Structure of Ph–Hg–N(SO₂Me)₂ Four N,N‐disulfonylated organylmercury(II) amides R–Hg–N(SO₂Me)₂, where R is Me, ⁱPr, Me₃SiCH₂ or Ph, were obtained on treating the appropriate chlorides RHgCl with AgN(SO₂Me)₂, and characterized by ¹H and ¹³C NMR spectra. In the crystal structure of the phenyl compound (orthorhombic, space group Pbca, Z = 8, X‐ray diffraction at –95 °C), the molecule exhibits a covalent and significantly bent C–Hg–N grouping [bond angle 172.7(3)°; Hg–C 204.0(8), Hg–N 209.1(7) pm]. One sulfonyl oxygen atom forms a short intramolecular Hg…O contact [296.1(5) pm] and simultaneously catenates glide‐plane related molecules via a second Hg…O interaction 297.6(5) pm], thus conferring upon Hg^II the effective coordination number 4 and a geometrically irregular coordination polyhedron (bond angles from 173 to 54°).     

Mercuric Bis(N‐imino‐methyl‐formamidate), Hg(Imf)2

Single crystals of mercuric bis(N‐imino‐methyl‐formamidate), Hg(Imf)₂, were obtained from aqueous solutions of 1,2,4‐triazole and Hg(NO₃)₂·2H₂O. The crystal structure [monoclinic, P2₁/c (no. 14), a = 499.6(2), b = 1051.2(4), c = 711.1(3) pm, β = 117.55(1)°, Z = 2, R₁ for 890 reflections with I₀>2σ(I₀): 0.0369] contains linear centrosymmetric Hg(Imf)₂ molecules with Hg–N distances of only 203.5(7) pm. Two plus two intra‐ and intermolecular nitrogen atoms add to an effective coordination number of 6.     

Synthese und Kristallstrukturen der Nitrido‐Chloro‐Molybdate [Mg(THF)4{NMoCl4(THF)}2] · 4 CH2Cl2 und [Li(12‐Krone‐4)(NMoCl4)]2 · 2 CH2Cl2

Syntheses and Crystal Structures of the Nitrido‐chloro‐molybdates [Mg(THF)₄{NMoCl₄(THF)}₂] · 4 CH₂Cl₂ and [Li(12‐Crown‐4)(NMoCl₄)]₂ · 2 CH₂Cl₂ Both the title compounds as well as [Li(12‐crown‐4)₂]⁺MoNCl₄^– were made from MoNCl₃ and the chlorides MgCl₂ and LiCl, respectively, in dichloromethane suspensions in the presence of tetrahydrofuran and 12‐crown‐4, respectively. They form orange‐red moisture‐sensitive crystals, which were characterized by their IR spectra and partly by crystal structure analyses. [Mg(THF)₄{NMoCl₄(THF)}₂] · 4 CH₂Cl₂ ( 1 ): space group C2/m, Z = 2, lattice dimensions at –50 °C: a = 1736.6(1), b = 1194.8(1), c = 1293.5(2) pm; β = 90.87(1)°; R₁ = 0.037. In 1 the magnesium ion is coordinated octahedrally by the oxygen atoms of the four THF molecules and in trans‐position by the nitrogen atoms of the two [N≡MoCl₄(THF)]^– ions. [Li(12‐crown‐4)(NMoCl₄)]₂ · 2 CH₂Cl₂ ( 2 ): space group P 1, Z = 1, lattice dimensions at –70 °C: a = 930.4(1), b = 957.9(1), c = 1264.6(1) pm; α = 68.91(1)°, β = 81.38(1)°, γ = 63.84(1)°; R₁ = 0.0643. 2 forms a centrosymmetric ion ensemble in the dimeric cation of which, i. e. [Li(12‐crown‐4)]₂²⁺, the lithium ions on the one hand are connected to the four oxygen atoms each of the crown ether molecules in a way not yet known; and in addition, each of the lithium ions enters into a intermolecular Li–O bond with neighboring crown ether molecules under formation of a Li₂O₂ four‐membered ring. The two N≡MoCl₄^– counterions are loosely coordinated to one oxygen atom each of the crown ether molecules with Mo–O distances of 320.2 pm.     

Mercurous Dimethylglyoximato Nitrate,Hg2(Dmg)2(NO3)2

Colourless needles of mercurous dimethylglyoximato nitrate, Hg₂(Dmg)₂(NO₃)₂, grow from a diluted nitric acid solution of mercurous nitrate and dimethylglyoxime. The crystal structure (triclinic, P1¯, a = 728.50(13), b = 1066.8(2), c = 1167.9(2) pm, α = 93.78(2)°, β = 94.16(2)°, γ = 98.61(2)°, R_all = 0, 0726) contains the cations [Hg₂(Dmg)₂]²⁺ and “non‐coordinating” (NO₃)^— anions. In the cation, two neutral dimethylglyoxime molecules coordinate bidentately with Hg—N distances in the narrow range of 236 to 239 pm to the mercurous ion, Hg₂²⁺, which exhibits a Hg—Hg bond distance of 252.23(8) pm).     

Synthese und Kristallstruktur von Cs3AuO2

Synthesis and Crystal Structure of Cs₃AuO₂ Bright orange single crystals of Cs₃AuO₂, sensitive to moisture and atmosphere, are obtained by reacting CsAu with a 1 : 1 molar mixture of Cs₂O and CsO₂ (CsAu : Cs₂O : CsO₂ = 3 : 2 : 2) in sealed silver crucibles under argon atmosphere at 380 °C for a period of 6 days. The crystal structure (Pearsoncode mP72, P2₁/n, a = 1019.6(3), b = 1984.3(7), c = 1028.5(4) pm, β = 93.96(1)°, Z = 12, 2562 reflections mit I_o > 2σ(I), R₁ = 0.0662, wR₂ = 0.1660) is characterized by the presence of dumb‐bell‐shaped [O–Au–O]‐moieties (d(Au–O) = 200,8(2) pm), a common feature of oxoaurates(I).     

Mono‐ and Dimethyl‐1,2,4‐Triazolate as Ligands for the Mercuric Ion in the Cationic Three‐dimensional Coordination Polymer of [Hg2(Mmt)(Dmt)2](NO3)(H2O)

Colourless crystals of [Hg₂(Mmt)(Dmt)₂](NO₃)(H₂O) were obtained from a reaction of mercuric nitrate with monomethyl‐ and dimethyl‐1,2,4‐triazolate (Mmt^? and Dmt^?, respectively). In the crystal structure (monoclinic, C2/c (no. 15), a = 2579.4(4), b = 1231.1(2), c = 1634.8(2) pm, β = 128.32(1)°, V = 4073.3(11)·10⁶·pm³, Z = 8, R₁ [I₀ > 2σ(I₀)]: 0.0355), half of the mercuric ions are essentially two‐coordinate (Hg–N: 210‐215 pm), the other half are tetrahedrally surrounded by N‐donor atoms (Hg–N: 221, 225 pm) of the Mmt^? and Dmt^? anions. These three‐N ligands construct a three‐dimensional framework.     

Darstellung und Kristallstrukturen der ersten Alkalimetall‐hexacarbonatooxotetraberyllate: K6[Be4O(CO3)6] · 7 H2O und K6[Be4O(CO3)6]

Preparation and Crystal Structures of the first Alkalimetall‐hexacarbonato‐oxotetraberyllates: K₆[Be₄O(CO₃)₆] · 7 H₂O and K₆[Be₄O(CO₃)₆] K₆[Be₄O(CO₃)₆] · 7 H₂O has been prepared by dissolving freshly precipitated Be(OH)₂ in an aqueous KHCO₃ solution. After enriching the title compound by extraction with ethanol the heptahydrate crystallizes from the organic phase (triklin, P1¯ (No. 2) with a = 951, 01(11), b = 958, 45(12), c = 1601, 7(2) pm, α = 79, 253(13)°, β = 78, 943(12)°, γ = 65, 119(12)°, V_EZ = 1290, 6(3)·10⁶ pm³, Z = 2). Thermal decomposition forms rhombohedral crystals of the anhydrous compound (trigonal‐rhombohedric, R3¯ (No. 148) with a = 1416, 42(6), c = 1704, 5(1) pm, V_EZ = 2961, 4(3)·10⁶ pm³, Z = 6).     

Synthese,Struktur und Eigenschaften der Komplexe [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)], [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)], [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] und [{(Me2PhP)2(CO)Cl2Re≡N}2ReNCl2(PMe2Ph)]

Synthesis, Crystal Structure, and Properties of the Complexes [(H₂O)Cl₄Os≡N‐IrCl(C₅Me₅)(AsPh₃)], [(Ph₃Sb)Cl₄Os≡N‐IrCl(C₅Me₅)(SbPh₃)], [(Ph₃Sb)₂Cl₃Os≡N‐IrCl(COD)] and [{(Me₂PhP)₂(CO)Cl₂Re≡N}₂ReNCl₂(PMe₂Ph)] The dinuclear complexes [(H₂O)Cl₄Os≡N‐IrCl(C₅Me₅)(AsPh₃)]·H₂O ( 1 ·H₂O), [(Ph₃Sb)Cl₄Os≡N‐IrCl(C₅Me₅)(SbPh₃)] ( 2 ), and [(Ph₃Sb)₂Cl₃Os≡N‐IrCl(COD)] ( 3 ) result from the reaction of the nitrido complexes [(Ph₃As)₂OsNCl₃] and [(Ph₃Sb)₂OsNCl₃] with the iridium compounds [IrCl₂(C₅Me₅)]₂ and [IrCl(COD)]₂ in dichloromethane. 1 crystallizes as 1 ·H₂O in form of green platelets in the monoclinic space group Cm and a = 1105.53(6); b = 1486.76(9); c = 2024.88(10) pm, β = 97.191(4)°, Z = 4. The formation of 1 in air involves a ligand exchange, and the coordination of a water molecule in trans position to the Os‐N triple bond. The resulting complex fragments [(H₂O)Cl₄Os≡N] and [IrCl(C₅Me₅)(AsPh₃)] are connected by an asymmetric nitrido bridge Os≡N‐Ir. The nitrido bridge is characterised by an Os‐N‐Ir bond angle of 173.7(7)°, and distances Os‐N = 168(1) pm and Ir‐N = 191(1) pm. 2 crystallizes in clumped together brown platelets with the space group and a = 1023.3(3), b = 1476.2(3), c = 1872.5(6) pm, α = 74.60(2), β = 73.84(2), γ = 76.19(2)°, Z = 2. In 2 the asymmetric nitrido bridge Os≡N‐Ir joins the two complex fragments [(Ph₃Sb)Cl₄Os≡N] and [IrCl(C₅Me₅)(SbPh₃)], which are formed by a ligand exchange reaction. 3 forms dark green crystals with the triclinic space group and a = 1079.4(1), b = 1172.3(1), c = 1696.7(2) pm, α = 101.192(9),β = 92.70(1), γ = 92.61(1)°, Z = 2. The distances in the almost linear nitrido bridge (Os≡N‐Ir = 175.3(7)°) are Os‐N = 171(1) pm and Ir‐N = 183(1) pm. The reaction of [ReNCl₂(PMe₂Ph)₃] with [Mo(CO)₃(NCMe)₃] unexpectedly affords the trinuclear complex [{(Me₂PhP)₂(OC)Cl₂Re≡N}₂ReNCl₂(PMe₂Ph)] ( 4 ) as the main product. It forms triclinic brown crystals with the composition 4 ·2THF and the space group (a = 1382.70(7), b = 1498.58(7), c = 1760.4(1) pm, α = 99.780(7), β = 99.920(7), γ = 114.064(6)°, Z = 2). In the trinuclear complex, the central fragment, [ReNCl₂(PMe₂Ph)] is joined in trans position to two nitrido complexes [(Me₂PhP)₂(CO)Cl₂Re≡N], giving an almost linear Re≡N‐Re‐N≡Re arrangement. The bond angles and distances in the nitrido bridges are Re‐N‐Re = 167.8(3)°, Re‐N = 171.1(8) pm and 204.2(8) pm; and Re‐N‐Re = 168.1(4)°, Re‐N = 170.9(9) and 203.5(9) pm respectively. As expected, the Re‐N bond length to the terminal nitrido ligand on the central Re atom is much shorter at 161.2(9) pm than the triple bonds of the asymmetric bridges.     

Über die Schichtstruktur von Cu2(H2O)4[C4H4N2][C6H2(COO)4]·2H2O

The Layered Structure of Cu₂(H₂O)₄[C₄H₄N₂][C₆H₂(COO)₄]·2H₂O Triclinic single crystals of Cu₂(H₂O)₄[C₄H₄N₂][C₆H₂(COO)₄]·2H₂O have been grown in an aqueous silica gel. Space group (Nr. 2), a = 723.94(7) pm, b = 813.38(14) pm, c = 931.0(2) pm, α = 74.24(2)°, β = 79.24(2)°, γ = 65.451(10)°, V = 0.47819(14) nm³, Z = 1. Cu²⁺ is coordinated in a distorted, octahedral manner by two water molecules, three oxygen atoms of the pyromellitate anions and one nitrogen atom of pyrazine (Cu—O 194.1(2)–229.3(3) pm; Cu–N 202.0(2) pm). The connection of Cu²⁺ and [C₆H₂(COO)₄)]^4? yields infinite strands, which are linked by pyrazine molecules to form a two‐dimensional coordination polymer. Thermogravimetric analysis in air showed that the dehydrated compound was stable between 175 and 248 °C. Further heating yielded CuO.     

Synthese und Struktur der Platin(O)-Verbindungen [(dipb)Pt]2(COD) und (dipb)3Pt2 sowie des clusters Hg6[Pt(dipb)]4 (dipb = (i-Pr)2P(CH2)4P(i-Pr)2)

Synthesis and Structure of the Platinum(0) Compounds [(dipb)Pt]₂(COD) and (dipb)₃Pt₂ and of the Cluster Hg₆[Pt(dipb)]₄ (dipb = (i-Pr)₂P(CH₂)₄P(i-Pr)₂) The reduction of (dipb)PtCl₂ with Na/Hg yields (dipb)Pt as an intermediate which reacts with the amalgam to form the cluster Hg₆[Pt(dipb)]₄ ( 3 ) or decomposes to (dipb)₃Pt₂ ( 2 ) and Pt. In the presence of COD [(dipb)Pt]₂(COD) ( 1 ) is obtained. 1 crystallizes monoclinicly in the space group P2₁/c with a = 1596.1(4), b = 996.5(2), c = 1550.4(3) pm, β = 113.65(2)°, Z = 2. In the dinuclear complex two (dipb)Pt units are bridged by a 1,2-η²-5,6-η² bonded COD ligand. Whereby the C = C double bonds are lengthened to 145 pm. 2 forms triclinic crystals with the space group P1 and a = 1002.0(2), b = 1635.9(3), c = 868.2(2) pm, α = 94.70(2)°, β = 94.45(2)°, σ = 87.95(1)°, Z = 1. In 2 two (dipb)Pt moieties are connected by a μ-dipb ligand in a centrosymmetrical arrangement. 3 is monoclinic with the space group C2/c and a = 1273.8(3), b = 4869.2(6), c = 1660.2(3) pm, β = 95.16(2)°, Z = 4. The clusters Hg₆[Pt(dipb)]₄ have the symmetry C₂. Central unit is a Hg₆ octahedron of which four faces are occupied by Pt(dipb) groups. The bonding in the cluster is discussed on the basis of eight Pt? Hg two center bonds of 267.6 pm and two Pt? Hg? Pt three center bonds with Pt? Hg = 288.0 pm.     

Thiocyanate Compounds of [Nb6Cl12]2+: The structure of A4[Nb6Cl12(NCS)6](H2O)4 (A = K,Rb, NH4)

New compounds of the general formula A₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ (A = K, Rb, NH₄) were synthesized from Nb₆Cl₁₄ and ASCN in aqueous solutions. X-ray structure refinements were performed on single-crystal data of the three compounds. They are isotypic and crystallize with the space group P1 (Z = 1) and the lattice parameters: a = 877.9(3) pm, b = 1176.6(3) pm, c = 1187.0(3) pm, α = 114.29(1)°, β = 98.96(2)°, γ = 100.91(2)° for K₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 1 ); a = 887.6(3) pm, b = 1184.0(4) pm, c = 1195.4(4) pm, α = 114.95(2)°, β = 98.84(2)°, γ = 101.31(2)° for Rb₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 2 ) and a = 886.0(4) pm, b = 1181.1(6) pm, c = 1183.9(6) pm, α = 114.49(2)°, β = 99.48(3)°, γ = 101.53(1)° for (NH₄)₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 3 ). Each centrosymmetric [Nb₆Cl₁₂(NCS)₆]^4? ion of the isotypic compounds contains six terminal thiocyanate groups being bound to the corners of the octahedral niobium cluster through the nitrogen atoms (d_{Nb? N} = 221.5(6)–224.3(6) pm, bond angles Nb? N? C 168.6(5)–176.4(6)°). The [Nb₆Cl₁₂(NCS)₆]^4? ions are linked via A? S and A? Cl interactions with the A cations. Half of the cations occur to be disordered along two crystallographic sites.     

Zwei Mercuri‐Ammin‐Komplexe: [Hg(NH3)2][HgCl3]2 und [Hg(NH3)4](ClO4)2

Two Mercuric Ammoniates: [Hg(NH₃)₂][HgCl₃]₂ and [Hg(NH₃)₄](ClO₄)₂ [Hg(NH₃)₂][HgCl₃]₂ ( 1 ) is obtained by saturating an equimolar solution of HgCl₂ and NH₄Cl with Hg(NH₂)Cl at 75 °C. 1 crystallizes in the orthorhombic space group Pmna with a = 591.9(1) pm, b = 800.3(1) pm, c = 1243.3(4) pm, Z = 2. The structure consists of linear cations [Hg(NH₃)₂]²⁺ and T‐shaped anions [HgCl₃]^—. The coordination sphere of mercury is ?effectively”? completed to compressed hexagonal bipyramids and distorted octahedra, respectively. Single crystals of [Hg(NH₃)₄](ClO₄)₂ ( 2 ) are obtained by passing gaseous ammonia through a solution of mercuric perchlorate, while the solution was cooled to temperatures below 10 °C. 2 crystallizes in the monoclinic space group P2₁/c with a = 791.52(9) pm, b = 1084.3(2) pm, c = 1566.4(2) pm, β = 120.352(1)°, Z = 4. The structure consists of compressed [Hg(NH₃)₄]²⁺ tetrahedra and perchlorate anions. The packing of the heavy atoms Hg and Cl is analogous to the baddeleyite (α‐ZrO₂) type of structure.     

Über die komplexen Hydroxide des Chroms: Na9[Cr(OH)6]2(OH)3 · 6 H2O und Na4[Cr(OH)6]X · H2O (X = Cl, (S2)1/2) – Synthese,Kristallstruktur und thermisches Verhalten

Complex Hydroxides of Chromium: Na₉[Cr(OH)₆]₂(OH)₃ · 6 H₂O and Na₄[Cr(OH)₆]X · H₂O (X = Cl, (S₂)_1/2) – Synthesis, Crystal Structure, and Thermal Behaviour Green plate‐like crystals of Na₉[Cr(OH)₆]₂(OH)₃ · 6 H₂O (triclinic, P1, a = 872.9(1) pm, b = 1142.0(1) pm, c = 1166.0(1) pm, α = 74.27(1)°, β = 87.54(1)°, γ = 70.69(1)°) are obtained upon slow cooling of a hot saturated solution of Cr^III in conc. NaOH (50 wt%) at room temperature. In the presence of chloride or disulfide the reaction yields green prismatic crystals of Na₄[Cr(OH)₆]Cl · H₂O (monoclinic, C2/c, a = 1138.8(2) pm, b = 1360.4(1) pm, c = 583.20(7) pm, β = 105.9(1)°) or green elongated plates of Na₄[Cr(OH)₆](S₂)_1/2 · H₂O (monoclinic, P2₁/c, a = 580.8(1) pm, b = 1366.5(3) pm, c = 1115.0(2) pm, β = 103.71(2)°), respectively. The latter compounds crystallize in related structures. All compounds can be described as distorted cubic closest packings of the anions and the crystal water molecules with the cations occupying octahedral sites in an ordered way. The thermal decomposition of the compounds was investigated by DSC/TG or DTA/TG and high temperature X‐ray powder diffraction measurements. In all cases the final decomposition product is NaCrO₂.     

The Crystal and Molecular Structure of Mercury Fulminate (Knallquecksilber)

A short survey on the fascinating history of mercury fulminate is given. The crystal structure of Hg(CNO)₂ has been determined using single crystal X‐ray diffraction. Mercury fulminate crystallizes in an orthorhombic cell, space group Cmce with a = 5.3549(2), b = 10.4585(5), c = 7.5579(4) Å and Z = 4. The distances and angles in the O‐N≡C‐Hg‐C≡N‐O molecule are Hg‐C 2.029(6) Å, C≡N 1.143(8) Å, N‐O 1.248(6) Å and C‐Hg‐C 180.0(1)°, Hg‐C≡N 169.1(5)°, C≡N‐O 179.7(6)°. Each mercury atom is surrounded by two oxygen atoms from neighbouring Hg(CNO)₂ molecules with a nonbonding distance of Hg···O 2.833(4) Å. The Hg‐C bond lengths in the linear Hg(CNO)₂ molecules are shorter than those in the tetrahedral complex [Hg(CNO)₄]^2?. This refers to a large contribution of the 6s orbital in the Hg‐C bonds of Hg(CNO)₂. The results of the X‐ray powder investigation on Hg(CNO)₂ are also reported.     

Einkristallzüchtung und Röntgenstrukturanalyse von CoSO4 · Pyrazin · 6 H2O (I) und (CoSO4)2 · Pyrazin · 12 H2O (II)

Crystal Growth and Structure of CoSO₄ · Pyrazine · 6 H₂O (I) and (CoSO₄)₂ · Pyrazine · 12 H₂O (II) Single crystals of μ-pyrazino-bis[pentaquacobalt(II)]-sulfate-dihydrate CoSO₄(pz) · 6 H₂O and Tetraqua-μ-pyrazino-cobalt(II)sulfate-dihydrate (CoSO₄)₂(pz) · 12 H₂O were grown by using gel methods and investigated by X-ray analysis. CoSO₄(pz) · 6 H₂O (I) shows monoclinic symmetry, space group C2/c; a = 1006.4(4) pm, b = 1026.9(4) pm, c = 1261.5(2) pm; β = 104.01(4)°; Z = 4. (CoSO₄)₂(pz) · 12 H₂O (II) shows orthorhombic symmetry, space group Pbam; a = 1262.3(4) pm, b = 1231.3(4) pm, c = 684.1(2) pm; Z = 2. CoSO₄ and Pyrazine crystallize in a polymeric (I) as well as in a dimeric (II) compound. In the polymeric compound the molecules are bonded by pyrazine to form alternating linear chains. The dimer is a dinuclear complex with a bridging pyrazine molecule.