Co(NH3)2Cl2 and Co(ND3)2Cl2: Order‐Disorder Behaviour of N(H, D)3 and Antiferromagnetic Structure

Diammine cobalt(II) chloride, Co(N(H, D)₃)₂Cl₂ was prepared by decomposition of the corresponding hexaammines at 120 °C in dynamical vacuum. Crystal structures and magnetic properties of these materials were characterised by X‐ray and neutron powder diffraction, and heat capacity measurements. At ambient temperatures Co(N(H, D)₃)₂Cl₂ crystallises in the Cd(NH₃)₂Cl₂ type structure: space group Cmmm, Z = 2, a = 8.0512(2) Å, b = 8.0525(2) Å, c = 3.73318(9) Å (X‐ray data of the H compound). This structure consists of chains of edge‐sharing octahedra [CoCl_4/2(NH₃)₂] running along the c‐axis. Neutron diffraction confirms that that the ND₃ groups are rotationally disordered at ambient temperatures. At 1.5 K and 20 K neutron diffraction data reveal rotational ordering of the ND₃ groups leading to doubling of the c‐axis and to Ibmm symmetry: a = 7.9999(6) Å, b = 7.9911(5) Å, c = 7.4033(3) Å (Z = 4, values for T = 1.5 K). Furthermore, antiferromagnetic ordering is present at these temperatures. It is caused by a ferromagnetic coupling of the magnetic moments at Co²⁺ (3.60(5) μ_B at 1.5 K, 3.22(5) μ_B at 20 K) along the octahedra chains [CoCl_4/2(NH₃)₂] and antiferromagnetic coupling between neighbouring chains. According to heat capacity measurements the phase transition antiferromagnetic‐paramagnetic takes place at T_N = 26 K.     

Neutronenbeugung an der Tieftemperaturmodifikation von Rubidiumdeuteroamid

Neutron Diffraction of the Low Temperature Modification of Rubidium Deutero Amide A polycrystalline sample of RbND₂ was prepared by reaction of liquid ND₃ and Rb (320 K, 4 d). Rietveld refinement of neutron powder diffraction data collected on the E2 (HMI-BENSC, Berlin) yielded the deuterium positions and allowed the temperature factors of all atoms to be refined anisotropically: space group P2₁/m, Z = 2, a = 4.846(1) Å, b = 4.136(1) Å, c = 6.396(2) Å, β = 98.051(7)°, N(I/σ_(I) > 1) = 179, N(Var.) = 25, R_P = 0.025, wR_P = 0.032, R_B(I/σ_(I) > 1) = 0.095. In a monoclinic distorted rock salt structure the amide ions are oriented antiferroelectrically in almost planar zick-zack chains.     

Neutronenpulverdiffraktionsmessungen an [Zn(ND3)4]I2 bei 1,5 K, 10 K und 293 K: Wasserstoff-Brückenbindungen und Bewegungen von ND3-Molekülen

Neutron Powder Diffraction Measurements on [Zn(ND₃)₄]I₂ at 1.5 K, 10 K, and 293 K: Hydrogen Bonds and Dynamic of ND₃ Molecules Microcrystalline powder of [Zn(ND₃)₄]I₂ can be prepared by the reaction of gaseous NH₃ with dry ZnI₂ at room temperature within 8 h. Neutron powder diffraction measurements at 1.5 K, 10 K and 293 K were used to localize all hydrogen atoms. Isolated [Zn(ND₃)₄]²⁺ tetrahedra are three dimensionally linked with 2- and 3-centre (bent and bifurcated) N? D …? I^?-hydrogen bonds. Ammonia molecules are ordered at 1.5 K. Room temperature high thermal displacement parameters for D hint to the fact that NH₃-dynamics take place. Lattice parameters 300 K [10 K; 1,5 K]: a = 10.3783(8) Å [10.3407(4) Å; 10.3381(5)], b = 7.5239(6) Å [7.3960(2) Å; 7.3935(4) Å], c = 13.088(1) Å [12.9731(4) Å; 12.9695(6) Å], space group: Pnma.     

The transformation of Sn(ND3)2F4 into Sn(ND2)2F2. Synthesis and neutron crystal structure determination of Sn(ND2)2F2

Diamido-difluoro-tin Sn(ND₂)₂F₂ can be produced by ammonolysis from (NH₄)₂SnF₆ at 633 K. The compound is a product formed from Sn(ND₃)₂F₄ during the ammonolysis reaction. Sn(ND₂)₂F₂ isostructural with Sn(NH₂)₂F₂ crystallizes in space group C2/m with lattice constants a = 1072.92(7), b = 325.97(1) pm, c = 505.79(4) pm and β = 105.713(6) ° (V = 170.28(1) ·10⁶ pm³) containing two formula units per unit cell. Data refinement by the Rietveld method of neutron time-of-flight data collected at POLARIS yields a weighted profile R-value R_wp = 0.022. Tin is octahedrally coordinated by two fluorine atoms and four amido groups. The octahedra are connected to one-dimensional chains by edge sharing. The ND₂ groups are in the bridging position whilst the fluorine atoms are terminal. Nearly linear (175.2(4) °) and angular (134.35(8) °) N-D···F hydrogen linkages connect the chains.     

Protonenlagen bei Kaliumtetraamidozinkat,K2Zn(NH2)4

Positions of the Protons in Potassium Tetraamidozincate, K₂Zn(NH₂)₄ X-ray single crystal data for K₂Zn(NH₂)₄ allowed the determination of the so far unknown positions of the protons: P1 , Z = 2, a = 6.730(1) Å, b = 7.438(1) Å, c = 8.019(2) Å, α = 72.03(2)°, β = 84.45(2)°, γ = 63.82(1)°, Z(F₀) with (F₀)² ≥ 3σ(F₀)² = 2166, Z(parameters) = 96, R/R_W = 0.032/0.039. In the structure of K₂Zn(NH₂)₂ the amide ions are nearly hexagonal close packed. One layer of octahedral holes parallel to (010) is fully occupied by potassium atoms and zinc is in an ordered way in a quarter of the tetrahedral holes of the next layer. The orientation of the protons of the amide ions is characteristic for this type of structure (filled up CdI₂ type).     

RbLi(NH2)2, a Rubidium Amido Lithiate Investigated by X‐Ray and Neutron Diffraction

RbLi(NH₂)₂ and the fully deuterated compound are obtained in autoclaves by the reaction of RbNH₂/RbND₂ and Li metal in supercritical NH₃/ND₃ (470 K, 220 Mpa, 41 d). X‐ray single crystal and neutron powder diffraction led to a new type of crystal structure closely related to the ThCr₂Si₂type. It is an orthorhombic distorted variant with an ordered half occupation by lithium on tetrahedral sites of puckered 4⁴ nets of amide ions to{[Li(NH₂)_1/1(NH₂)_3/3]} units and fully filled up sites of CN = 8 by Rb. The compound crystallizes in the space group Pnma with Z = 4 and a = 7.772 (2)Å, b = 3.843 (1)Å, c = 11.583 (2)Å. It contains an unexpected hydrogen bridge bonding system between crystallographic different amide ions.     

Die Kristallstruktur von Bariumamid,Ba(NH2)2

The Crystal Structure of Barium Amide, Ba(NH₂)₂ Single crystals of barium amide can be obtained by the reaction of barium metal with ammonia during long times. At ? 70° C Ba reacts with the solvent very slowly. The resulting amide then is well crystallized. Crystals can also be grown at 125° C in a temperature grakient. In both cases 3 to 4 months are necessary to get crystals of about 0.1 mm in diameter. Barium amide is monoclinic a = 8.951 Å, b = 12.67 Å, c = 7.037 Å, und β = 123.5° with 8 formula units. The space group is Cc. All atoms occupy the general position. The structure of Ba(NH₂)₂ shows two different Ba atoms with respect to their surrounding. One of them is coordinated irregularly by 8 amide ions, the other by 7 amide ions. The nitrogen atoms have 11 neighbours to each other. This means, that they are relatively close packed. Barium amide has a coorkination type structure, whereas the low symmetry of the arrangement of the different ions may be explained by the dipole chracter of the anion, and by packing effects.     

Na2Mn(NH2)4: Ein neuer Schichtenstrukturtyp

Na₂Mn(NH₂)₄: A New Type of Layered Structure The structure of Na₂Mn(NH₂)₄ was solved by X-ray single crystal data including H-positions: P2₁/c, Z = 4, a = 6.331(1) Å, b = 14.542(3) Å, c = 7.212(1) Å, β = 116.29(1)°, Z(F ≥ 3σ = (F)) = 1343, Z(parameters) = 96, R/R_W = 0.023/0.029. The compound crystallizes in a new type of structure. Within layered blocks the amide ions are arranged with the motif of a hexagonal closest packing of spheres. Within these blocks alternating layers contain sodium in all octahedral sites and manganese in an ordered way in a quarter of tetrahedral sites.     

Synthese und Kristallstruktur von K2(HSO4)(H2PO4), K4(HSO4)3(H2PO4) und Na(HSO4)(H3PO4)

Synthesis and Crystal Structure of K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄), and Na(HSO₄)(H₃PO₄) Mixed hydrogen sulfate phosphates K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄) and Na(HSO₄)(H₃PO₄) were synthesized and characterized by X‐ray single crystal analysis. In case of K₂(HSO₄)(H₂PO₄) neutron powder diffraction was used additionally. For this compound an unknown supercell was found. According to X‐ray crystal structure analysis, the compounds have the following crystal data: K₂(HSO₄)(H₂PO₄) (T = 298 K), monoclinic, space group P 2₁/c, a = 11.150(4) Å, b = 7.371(2) Å, c = 9.436(3) Å, β = 92.29(3)°, V = 774.9(4) ų, Z = 4, R₁ = 0.039; K₄(HSO₄)₃(H₂PO₄) (T = 298 K), triclinic, space group P 1, a = 7.217(8) Å, b = 7.521(9) Å, c = 7.574(8) Å, α = 71.52(1)°, β = 88.28(1)°, γ = 86.20(1)°, V = 389.1(8)ų, Z = 1, R₁ = 0.031; Na(HSO₄)(H₃PO₄) (T = 298 K), monoclinic, space group P 2₁, a = 5.449(1) Å, b = 6.832(1) Å, c = 8.718(2) Å, β = 95.88(3)°, V = 322.8(1) ų, Z = 2, R₁ = 0,032. The metal atoms are coordinated by 8 or 9 oxygen atoms. The structure of K₂(HSO₄)(H₂PO₄) is characterized by hydrogen bonded chains of mixed H_nS/PO₄^– tetrahedra. In the structure of K₄(HSO₄)₃(H₂PO₄), there are dimers of H_nS/PO₄^– tetrahedra, which are further connected to chains. Additional HSO₄^– tetrahedra are linked to these chains. In the structure of Na(HSO₄)(H₃PO₄) the HSO₄^– tetrahedra and H₃PO₄ molecules form layers by hydrogen bonds.     

Bismuth Polyanions in Solution: Synthesis and Structural Characterization of (2, 2, 2‐crypt‐A)2Bi4 (A = K,Rb) and the Formation of the Laves Phases ABi2 (A = K,Rb, Cs) from Solution

The possibility to synthesize and isolate different types of bismuth polyanions by dissolving various intermetallic precursors (binary samples from A‐Bi or ternary samples from A‐A'‐Bi systems, A and A' = K, Rb, Cs) in ethylenediamine or dimethylform amide in the presence of sequestering agents (2, 2, 2‐crypt or 18‐crown‐6) was investigated. The crystals of (2, 2, 2‐crypt‐K)₂Bi₄ ( 1 ) and (2, 2, 2‐crypt‐Rb)₂Bi₄ ( 2 ) compound were obtained from such solutions, the latter for the first time, and their structures were determined. The two compounds are isostructural (P1, Z=1, a = 11.052(2) Å, b = 11.370(2) Å, c = 11.698(2) Å, α = 61.85(3) °, β = 82.58(3) °, γ = 81.87(3) °, R₁ = 0.058, wR² = 0.149 for 1 and a = 11.181(2) Å, b = 11.603(2) Å, c = 11.740(2) Å, α = 61.96(3) °, β = 81.45(3) °, γ = 82.26(3) °, R₁ = 0.041, wR² = 0.109) and contain Bi₄^2— square planar cluster anions and cryptated alkali metal cations. In the case of the presence of 18‐crown‐6 the Laves phases ABi₂ (A = K, Rb, Cs) could be isolated from the solutions. A mechanism for the formation of ABi₂ is proposed.     

Protonation and Hydrogen Atom Abstraction Reactions in the Synthesis of the [HP7M(CO)3]2– Ions (M = Cr,W)

Ethylenediamine (en) solutions of [P₇M(CO)₃]^3– (M = Cr, W) react with weak acids to give [HP₇M(CO)₃]^2– ions where M = Cr ( 4 a ) and W ( 4 b ) in high yields. Competition studies with known acids revealed a pK_a range for 4 b in DMSO of 17.9 to 22.6. The [P₇M(CO)₃]^3– complexes also react with one-half equivalent of I₂ to give 4 through an oxidation/hydrogen atom abstraction process. Labeling studies show that the abstracted hydrogen originates from the [K(2,2,2-crypt)]⁺ ions or from the solvent (DMSO-d₆) in the absence of [K(2,2,2-crypt)]⁺ or other good hydrogen atom donors. In the solid state, the ions have no crystallographic symmetry but in solution they show virtual C_s symmetry (³¹P NMR spectroscopy) due to an intramolecular wagging process. Crystallographic data for [K(2,2,2-crypt)]₂[HP₇W(CO)₃]: triclinic, P 1, a = 10.9709(8) Å, b = 13.9116(10) Å, c = 19.6400(14) Å, α = 92.435(6)°, β = 93.856(6)°, γ = 108.413(6)°, V = 2831.2(4) ų, Z = 2, R(F) = 7.65%, R(wF²) = 14.17% for all 7400 reflections. For [K(2,2,2-crypt)]₂[HP₇Cr(CO)₃]: triclinic, P 1, a = 12.000(3) Å, b = 14.795(3) Å, c = 17.421(4) Å, α = 93.01(2)°, β = 93.79(2)°, γ = 110.72(2)°, V = 2877(2) ų, Z = 2.     

Wasserstoffbrückenbindungen in den Monoammoniakaten von Kalium‐ und Caesiumamid

Hydrogen Bonds in the Monoammoniates of Potassium and Cesium Amide X‐ray structure determination was carried out on the monoammoniates of potassium and cesium amide. Crystals of KNH₂ · NH₃ were grown from liquid NH₃ at 50 °C > T > 20 °C. They crystallize in the cold part of a pressure resistant glass apparatus. Single crystals of CsNH₂ · NH₃ were obtained by zone‐melting at —30 °C in x‐ray capillaries. The following data characterize the crystal chemistry of the compounds: KNH₂ · NH₃ Cmc2₁, Z = 4 21 °C a = 3, 938(1) Å, b = 10, 983(3) Å, c = 5, 847(1) Å CsNH₂ · NH₃ Pnma, Z = 4 30 °C a = 7, 103(1) Å, b = 5, 390(1) Å, c = 10, 106(2) Å For CsNH₂ · NH₃ all hydrogen atom positions were successfully refined. The structure of both ammoniates may be described by a distorted hexagonal close packed arrangement of cations with the NH₃ molecules in the octahedral and the NH₂^— anions in the trigonal bipyramidal interstices. The three H atoms of the NH₃ molecules are involved in hydrogen bridge bonds to two amide ions with d(N(NH₃)···N(NH₂^—)) = 2.60Å for the K and 3.19Å for the Cs compound and to a further NH₃ molecule with d(N(NH₃)···N(NH₃)) = 2.98Å for the K and 3.56Å for the Cs compound. Structural relationship of the ammoniates to the monohydrates of KOH and RbOH is discussed.     

Novel Alkaline Earth Metal Chalcogenoborates: Syntheses and Crystal Structures of Sr4.2Ba2.8(BS3)4S and Ba7(BSe3)4Se

Systematic studies on quaternary thio‐ and selenoborates containing heavier alkaline earth metal cations led to the two new isotypic crystalline phases Sr_4.2Ba_2.8(BS₃)₄S and Ba₇(BSe₃)₄Se. Both compounds consist of trigonal‐planar BQ₃ (Q = S, Se) units, isolated Q^2– anions and the corresponding counter‐ions. The two new chalcogenoborates were prepared in solid state reactions from the metal sulfides (selenides), amorphous boron and sulfur (selenium). Evacuated carbon coated silica tubes were used as reaction vessels since temperatures up to 870 K were applied. Sr_4.2Ba_2.8(BS₃)₄S and Ba₇(BSe₃)₄Se crystallize in the monoclinic space group C2/c (no. 15) with a = 9.902(3) Å, b = 23.504(9) Å, c = 9.884(3) Å, β = 90.01(3)° and Z = 4 in the case of the thioborate, while for the selenoborate the lattice parameters a = 10.513(2) Å, b = 25.021(5) Å, c = 10.513(2) Å, β = 90.10(3)° were determined. X‐ray powder patterns are compared to calculated diffraction data obtained from single crystal X‐ray structure determination.     

Darstellung und KristallStruktur des Rubidiumcalciumamids,RbCa(NH2)3

Preparation and Crystal Structure of the Rubidium Calcium Amide, RbCa(NH₂)₃ In the system Rb/Ca/NH₃ a ternary amide, RbCa(NH₂)₃, has been prepared by the reaction of the metals with supercritical NH₃ at T = 573 K and P = 5 000 bar. The x-ray investigation of single crystals of the compound led to the structure: a = 7.080 ± 0.006 Å, b = 11.95 ± 0.01 Å, c = 6.540 ± 0.006 Å, and β = 108.5 ± 0.1°; space group: C2/c ? No. 15, Z = 4. The atomic arrangement shows onedimensional infinite face-sharing anion-octahedra, which are occupied by calcium. The rubidium connects the octahedra-chains. The orientation of the protons corresponds to the stronger electrostatic influence of the calcium – compared with that of the rubidium ions.     

Crystal structures and properties of SrLnCuS3 (Ln = La,Pr)

The crystal structures of SrLnCuS₃ (Ln = La, Pr) have been refined using X-ray powder diffraction data and the derivative difference minimization method in the anisotropic approximation for all atoms. The crystals are orthorhombic, space group Pnma, BaLaCuS₃ structural type, unit cell parameters a = 11.2415(1) Å, b = 4.11053(6) Å, c = 11.5990(1) Å, V = 535.97(1) ų (SrLaCuS₃) and a = 11.1171(1) Å, b = 4.09492(6) Å, c = 11.5069(2) Å, V = 523.84(1) ų (SrPrCuS₃). The crystallographic positions of strontium and lanthanides are mixed by 21 and 11%, respectively. The SrLa-S and SrPr-S bond lengths range from 2.969(3) to 3.131(3) Å and from 2.924(2) to 3.056(2) Å, respectively. Distorted CuS₄ tetrahedra form chains running along the b axis. One-capped Sr/LnS₇ trigonal prisms form a three-dimensional structure with channels accommodating copper ions. The temperatures and enthalpies of incongruent melting are, respectively, 1513 K and 18 J/g (SrLaCuS₃) and 1426 K and 34 J/g (SrPrCuS₃). The compounds are IR transparent in the region of 3000–1800 cm^?1.     

Dimolybdenum Complexes Containing Pairs of Bridging Diphosphine and Carboxylate Ligands. Synthesis and Structures of trans-Mo2(O2CCH3)2(μ-dppa)2(BF4)2 and trans-Mo2X2(O2C(CH2)nCH3)2(μ-dppa)2 (n = 2, 10 or 12; X = Cl or Br; dppa = N,N-Bis(diphenylphosphino)amine)

The red complex trans-Mo₂(O₂CCH₃)₂(μ-dppa)₂(BF₄)₂, 1 , was prepared by reaction of [Mo₂(O₂CCH₃)₂(CH₃CN)₆][BF₄]₂ with dppa (dppa = Ph₂PN(H)PPh₂) in THF. The reactions of Mo₂(O₂C(CH₂)_nCH₃)₄ with dppa and (CH₃)₃SiX (X = Cl or Br) afforded the complexes trans-Mo₂X₂(O₂C(CH₂)_nCH₃)₂(μ-dppa)₂ (X = Cl, n = 2, 2; X = Br, n = 2, 3; X = Cl, n = 10, 4 ; X = Cl, n = 12, 5 ). Their UV-vis, IR and ³¹P{¹H}-NMR spectra have been recorded and the structures of 1, 2 and 3 have been determined. Crystal data for 1 : space group P2₁/n, a = 12.243(1) Å, b = 17.222(1) Å, c = 13.266(1) Å, β = 95.529(1)°, V = 2784.1(6) ų, Z = 2, with final residuals R = 0.0509 and Rw = 0.0582. Crystal data for 24CH₃Cl₂: space group P2₁/n, a = 13.438(1) Å, b = 19.276(1) Å, c = 14.182(1) Å, β = 111.464(1)°, V = 3418.9(6) ų, Z = 2, with final residuals R = 0.0492 and Rw = 0.0695. Crystal data for 3·4CH₂Cl₂: space group P2₁/n, a= 13.579(1) Å, b = 19.425(1) Å, c = 14.199(1) Å, β = 111.881(2)°, V = 3475.6(7) ų, Z = 2, with final residuals R = 0.0703 and Rw = 0.0851. Comparison of the structural data shows that the effect of the axial ligand on weakening the Mo-Mo bond strength is X^? > CH₃CN > BF₄^?. The T_m values are 121.7 °C for 2 , 111.1 °C for 3 and 91.5 °C for 5 , respectively.     

Synthesis and crystal structure of two fluorophosphated compounds with different infinite sheets: Sr2Ga(HPO4)(PO4)F2 and Sr2Fe2(HPO4)(PO4)2F2

New compounds, Sr₂Ga(HPO₄)(PO₄)F₂ and Sr₂Fe₂(HPO₄)(PO₄)₂F₂, have been prepared by hydrothermal synthesis (700°C, 180 MPa, 24 h) and characterized by single-crystal X-ray diffraction. Sr₂Ga(HPO₄)(PO₄)F₂ crystallizes in the monoclinic space group P2₁/n with a = 8.257(1) Å, b = 7.205(1) Å, c = 13.596(2) Å, β = 108.02(1)°, V = 769.2(2) ų and Z = 4 and Sr₂Fe₂(HPO₄)(PO₄)₂F₂ in the triclinic space group P2₁/n with a = 8.072(1) Å, b = 8.794(1) Å, c = 8.885(1) Å, α = 102.46(1)°, β = 115.95(1)°, γ = 89.95(1)°, V = 550.6(1) ų and Z = 2. Structures are both based on different sheets involving corner-linkage between octahedra and tetrahedra. The sheets are linked by Sr²⁺ cations. Structural relationships exist between the descloizite mineral and the title compounds.     

Preparation and Structure Determination of SrMn2(PO4)2 and Redetermination of b ′‐Mn3(PO4)2

Pale rose single crystals of SrMn₂(PO₄)₂ were obtained from a mixture of SrCl₂ · 6 H₂O, Mn(CH₃COO)₂, and (NH₄)₂HPO₄ after thermal decomposition and finally melting at 1100 °C. The new crystal structure of strontium manganese orthophosphate [P‐1, Z = 4, a = 8.860(6) Å, b = 9.054(6) Å, c = 10.260(7) Å, α = 124.27(5)°, β = 90.23(5)°, γ = 90.26(6)°, 4220 independent reflections, R1 = 0.034, wR2 = 0.046] might be described as hexagonal close‐packing of phosphate groups. The octahedral, tetrahedral and trigonal‐bipyramidal voids within this [PO₄] packing provide different positions for 8‐ and 10‐fold [SrO_x] and distorted octahedral [MnO₆] coordination according to a formulation Mn Mn Mn Sr (PO₄)₄. Single crystals of β′‐Mn₃(PO₄)₂ (pale rose) were grown by chemical vapour transport (850 °C → 800 °C, P/I mixtures as transport agent). The unit cell of β′‐Mn₃(PO₄)₂ [P2₁/c, Z = 12, a = 8.948(2) Å, b = 10.050(2) Å, c = 24.084(2) Å, β = 120.50°, 2953 independent reflections, R1 = 0.0314, wR2 = 0.095] contains 9 independent Mn²⁺. The reinvestigation of the crystal structure led to distinctly better agreement factors and significantly reduced standard deviations for the interatomic distances.     

Hydrothermal Synthesis of Rare Earth Iodates from the Corresponding Periodates: Structures of Sc(IO3)3, Y(IO3)3 · 2 H2O,La(IO3)3 · 1/2 H2O and Lu(IO3)3 · 2 H2O

Hydrothermal syntheses of single crystals of rare earth iodates, by decomposition of the corresponding periodate, are presented. This appears to be a generic method for making rare earth iodate crystals in a short period of time. Single crystal X‐ray diffraction structures of the four title compounds are presented. Sc(IO₃)₃: Space group R3, Z = 6, lattice dimensions at 100 K; a = b = 9.738(1), c = 13.938(1) Å; R₁ = 0.0383. Y(IO₃)₃ · 2 H₂O: Space group P1, Z = 2, lattice dimensions at 100 K: a = 7.3529(2), b = 10.5112(4), c = 7.0282(2) Å, α = 105.177(1)°, β = 109.814(1)°, γ = 95.179(1)°; R₁ = 0.0421. La(IO₃)₃ · ? H₂O: Space group Pn, Z = 2, lattice dimensions at 100 K: a = 7.219(2), b = 11.139(4), c = 10.708(3) Å, β = 91.86(1)°; R₁ = 0.0733. Lu(IO₃)₃ · 2 H₂O: Space group P1, Z = 2, lattice dimensions at 120 K: a = 7.2652(9), b = 7.4458(2), c = 9.3030(3) Å, α = 79.504(1)°, β = 84.755(1)°, γ = 71.676(2)°; R₁ = 0.0349.     

Benzeneselenolates of Mercury(II). Crystal and Molecular Structures of [Hg(SePh)2] and (Bu4N)[Hg(SePh)3]

The reaction of dibenzenediselenide, (SePh)₂, with mercury in refluxing xylene gives bis(benzeneselenolato)mercury(II), [Hg(SePh)₂], in a good yield. (ⁿBu₄N)[Hg(SePh)₃] is obtained by the reaction of [Hg(SePh)₂] with a solution of [SePh]^– and (ⁿBu₄N)Br in ethanol. The solid state structures of both compounds have been determined by X-ray diffraction. The mercury atom in [Hg(SePh)₂] (space group C2, a = 7.428(2), b = 5.670(1), c = 14.796(4) Å, β = 103.60(1)°) is linearly co-ordinated by two selenium atoms (Hg–Se = 2.471(2) Å, Se–Hg–Se = 178.0(3)°). Additional weak interactions between the metal and selenium atoms of neighbouring molecules (Hg…Se = 3.4–3.6 Å) associate the [Hg(SePh)₂] units to layers. The crystal structure of (ⁿBu₄N)[Hg(SePh)₃] (space group P2₁/c, a = 9.741(1), b = 17.334(1), c = 21.785(1) Å, β = 95.27(5)°) consists of discrete complex anions and (ⁿBu₄N)⁺ counter ions. The coordination geometry of mercury is distorted trigonal-planar with Hg–Se distances ranging between 2.5 and 2.6 Å.