Crystal Structure of New One-Dimensional Triple Molybdate Na<Subscript>2</Subscript>K<Subscript>2</Subscript>Cu(MoO<Subscript>4</Subscript>)<Subscript>3</Subscript>

The title compound (disodium dipotassium copper(II) tris-[molybdate (VI)]) is prepared by form melt and characterized by single crystal X-ray diffraction and UV-vis spectroscopy. It crystallizes in the triclinic space group P-1 with a = 7.4946(8) Å, b = 9.3428(9) Å, c = 9.3619(9) Å, α = 92.591(7)°, β = 105.247(9)°, γ = 105.496(9)°, V = 604.7 ų, and Z = 2. Its structure is isotypic with that of Na₄Mn(MoO₄)₃. It is formed by Cu₂O₁₀ distorted bi-octahedral dimers linked by two bridging bidentate Mo₂O₄ tetrahedra and, additionally, two monodentate Mo₁O₄ tetrahedra to form Cu₂Mo₄O₂₀ units. These units are linked by the insertion of Mo₃O₄ tetrahedra to build infinite ribbons disposed along the c axis. All of these ribbons form a one-dimensional framework. Both K1 and K3 cations are located in the inversion center, and all the other atoms are at general positions. The structure model is supported by the bond valence sum (BVS) and charge distribution CHARDI methods. The Cu²⁺ cations adopt the [4+2] CuO₆ Jahn-Teller distortion giving rise to an intense d–d transition in the UV-vis absorption spectra.     

Synthesis and Crystal Structure of CsCu3O2, Containing a New Type of Oxocuprate(I) Polyanion

CsCu₃O₂ was prepared via the azide route. Stoichiometric mixtures of the precursors (CsN₃, Cu₂O and CuO) were heated in a special regime up to 450 °C and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of as prepared powders at 450 °C for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X‐ray analysis of the crystal structure (P3¯m1, Z = 1, a = 5.250(1), c = 5.442(1)Å, γ = 120°) copper is linearly coordinated by oxygen atoms. The CuO₂‐dumb‐bells are connected to an infinite two‐dimensional Cu₃O₂‐network. CsCu₃O₂ is isostructural with CsCu₃S₂, CsAu₃S₂, CsAu₃Se₂ and RbAu₃Se₂.     

Darstellung und Kristallstruktur von Na2Mn3O7

Synthesis and Crystal-Structure of Na₂Mn₃O₇ Single crystals of Na₂Mn₃O₇ have been grown hydrothermally applying high oxygen pressure (p = 2 kbar). The new compound cystallizes triclinic; space group P1 ; a = 6.636(6) Å, b = 6.854(6) Å, c = 7.548(6) Å, α = 105.76(6)°, β = 106.86(6)°, γ = 111.60(6)°; Z = 2. The crystal structure has been solved and refined to R = 7.9% and R_w = 6.2% (diffractometer data, 1044 independent reflexions). The crystal structure consists of Mn₃O₇^2? anions with manganese coordinated octahedrally by oxygen. These layered anions are hold together by Na⁺ ions (coordination numbers 5 and 6).     

Synthesis and Characterization of the New Copper Indium Phosphate Cu8In8P4O30

The system CuO/In₂O₃/P₂O₅ has been investigated using solid state reaction between CuO, In₂O₃ and (NH₄)₂HPO₄ in silica glass crucibles at 900 °C. The powder samples were characterized by X‐ray diffraction, thermal analysis and FT‐IR spectroscopy. Orange single crystals of the new quaternary phase were achieved by the process of crystallization with mineralizers in sealed silica glass ampoules. They were then analyzed with EDX and single‐crystal X‐ray analysis in which the composition Cu₈In₈P₄O₃₀ with the triclinic space group P$\bar{1}$ (No 2) with a = 7,2429(14) Å, b = 8,8002(18) Å, c = 10,069(2) Å, α = 103,62(3)°, β = 106,31(3)°, γ = 101,55(3)° and Z = 1 was found. The three‐dimensional framework consists of [InO₆] octahedra and distorted [CuO₆] octahedra, overcaped [InO₇] prisms and [PO₄] tetrahedra, also trigonal [(CuIn)O₅] bipyramids and distorted [(CuIn)O₆] octahedra, where copper and indium are partly exchanged against each other. Cu₈In₈P₄O₃₀ exhibits an incongruent melting point at 1023 °C.     

Na2BaCuV2O8: Ein neuer Strukturtyp der Alkali-Erdalkalimetall Kupfer-Oxovanadate

Na₂BaCuV₂O₈: A New Structure Type of the Alkaline-Alkaline Earth Copper Oxovanadates Single crystals of Na₂BaCuV₂O₈ were prepared by a high temperature flux. It crystallizes with monoclinic symmetry space group C–C2/c, a = 9.4329 Å, b = 5.6858 Å, c = 14.0488 Å, β = 92.344° Z = 4 and represents a new structure type. The crystal structure show VO₄ tetrahedra, stretched CuO₆ octahedra, trigonal bipyramids around Na⁺ and a BaO₁₀₊₂ polyedron.     

Sodium hydrogen bis­(phenoxy­acetate)

In the title compound, Na⁺·H⁺·2C₈H₇O₃⁻, the anion contains a short Speakman-type hydrogen bond [O⃛O = 2.413 (2) Å]. The anions and the Na atoms lie across twofold axes.     

Two Novel CuII Phenanthroline Adipato Complexes with π‐π Stacking Interactions: [Cu(phen)2(C6H8O4)] · 4.5 H2O and [(Cu2(phen)2Cl2)(C6H8O4)] · 4 H2O

The blue copper complex compounds [Cu(phen)₂(C₆H₈O₄)] · 4.5 H₂O ( 1 ) and [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)] · 4 H₂O ( 2 ) were synthesized from CuCl₂, 1,10‐phenanthroline (phen) and adipic acid in CH₃OH/H₂O solutions. [Cu(phen)₂‐ (C₆H₈O₄)] complexes and hydrogen bonded H₂O molecules form the crystal structure of ( 1 ) (P1 (no. 2), a = 10.086(2) Å, b = 11.470(2) Å, c = 16.523(3) Å, α = 99.80(1)°, β = 115.13(1)°, γ = 115.13(1)°, V = 1617.5(5) ų, Z = 2). The Cu atoms are square‐pyramidally coordinated by four N atoms of the phen ligands and one O atom of the adipate anion (d(Cu–O) = 1.989 Å, d(Cu–N) = 2.032–2.040 Å, axial d(Cu–N) = 2.235 Å). π‐π stacking interactions between phen ligands are responsible for the formation of supramolecular assemblies of [Cu(phen)₂(C₆H₈O₄)] complex molecules into 1 D chains along [111]. The crystal structure of ( 2 ) shows polymeric [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains (P1 (no. 2), a = 7.013(1) Å, b = 10.376(1) Å, c = 11.372(3) Å, α = 73.64(1)°, β = 78.15(2)°, γ = 81.44(1)°, V = 773.5(2) ų, Z = 1). The Cu atoms are fivefold coordinated by two Cl atoms, two N atoms of phen ligands and one O atom of the adipate anion, forming [CuCl₂N₂O] square pyramids with an axial Cl atom (d(Cu–O) = 1.958 Å, d(Cu–N) = 2.017–2.033 Å, d(Cu–Cl) = 2.281 Å; axial d(Cu–Cl) = 2.724 Å). Two square pyramids are condensed via the common Cl–Cl edge to centrosymmetric [Cu₂Cl₂N₄O₂] dimers, which are connected via the adipate anions to form the [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains. The supramolecular 3 D network results from π‐π stacking interactions between the chains. H₂O molecules are located in tunnels.     

Synthesis, structure and properties of new chain cuprates, Na3Cu2O4 and Na8Cu5O10

Na₃Cu₂O₄ and Na₈Cu₅O₁₀ were prepared via the azide/nitrate route from stoichiometric mixtures of the precursors CuO, NaN₃ and NaNO₃. Single crystals have been grown by subsequent annealing of the as prepared powders at 500 °C for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structures (Na₃Cu₂O₄: P2₁/n, Z=4, a=5.7046(2), b=11.0591(4), c=8.0261(3) Å, β=108.389(1)°, 2516 independent reflections, R₁(all)=0.0813, wR₂ (all)=0.1223; Na₈Cu₅O₁₀: Cm, Z=2, a=8.228(1), b=13.929(2), , β=111.718(2)°, 2949 independent reflections, R₁(all)=0.0349, wR₂ (all)=0.0850), the main feature of both crystal structures are CuO₂ chains built up from planar, edge-sharing CuO₄ squares. From the analysis of the Cu-O bond lengths, the valence states of either +2 or +3 can be unambiguously assigned to each copper atom. In Na₃Cu₂O₄ these ions alternate in the chains, in Na₈Cu₅O₁₀ the periodically repeated part consists of five atoms according to Cu^II-Cu^II-Cu^III-Cu^II-Cu^III. The magnetic susceptibilities show the dominance of antiferromagnetic interactions. At high temperatures the compounds exhibit Curie-Weiss behaviour (Na₃Cu₂O₄: , , Na₈Cu₅O₁₀: , , magnetic moments per divalent copper ion). Antiferromagmetic ordering is observed to occur in these compounds below 13 K (Na₃Cu₂O₄) and 24 K (Na₈Cu₅O₁₀).     

CoSm(SeO3)2Cl,CuGd(SeO3)2Cl,MnSm(SeO3)2Cl,CuGd2(SeO3)4 und CuSm2(SeO3)4: Übergangsmetallhaltige Selenite von Samarium und Gadolinum

CoSm(SeO₃)₂Cl, CuGd(SeO₃)₂Cl, MnSm(SeO₃)₂Cl, CuGd₂(SeO₃)₄ and CuSm₂(SeO₃)₄: Transition Metal containing Selenites of Samarium and Gadolinum The reaction of CoCl₂, Sm₂O₃, and SeO₂ in evacuated silica ampoules lead to blue single crystals of CoSm(SeO₃)₂Cl (triclinic, , Z = 4, a = 712.3(1), b = 889.5(2), c = 1216.2(2) pm, α = 72.25(1)°, β = 71.27(1)°, γ = 72.08(1)°, R_all = 0.0586). If MnCl₂ is used in the reaction light pink single crystals of MnSm(SeO₃)₂Cl (triclinic, , Z = 2, a = 700.8(2), b = 724.1(2), c = 803.4(2) pm, α = 86.90(3)°, β = 71.57(3)°, γ = 64.33(3)°, R_all = 0.0875) are obtained. Green single crystals of CuGd₂(SeO₃)₂Cl (triclinic, , Z = 4, a = 704.3(4), b = 909.6(4), c = 1201.0(7) pm, α = 70.84(4)°, β = 73.01(4)°, γ = 70.69(4)°, R_all = 0.0450) form analogously in the reaction of CuCl₂ and Gd₂O₃ with SeO₂. CoSm(SeO₃)₂Cl contains [CoO₄Cl₂] octahedra, which are connected via one edge and one vertex to infinite chains. The Mn²⁺ ions in MnSm(SeO₃)₂Cl are also octahedrally coordinated by four oxygen and two chlorine ligands. The linkage of the polyhedra to chains occurs exclusively via edges. Both, the cobalt and the manganese compound show the Sm³⁺ ions in eight and ninefold coordination of oxygen atoms and chloride ions. In CuGd(SeO₃)₂Cl the Cu²⁺ ions are coordinated by three oxygen atoms and one Cl^— ion in a distorted square planar manner. One further Cl^— and one further oxygen ligand complete the [CuO₃Cl] units yielding significantly elongated octahedra. The latter are again connected to chains via two common edges. For the Gd³⁺ ions coordination numbers of ?8 + 1”? and nine were found. Single crystals of the deep blue selenites CuM₂(SeO₃)₄ (M = Sm/Gd, monoclinic, P2₁/c, a = 1050.4(3)/1051.0(2), b = 696.6(2)/693.5(1), c = 822.5(2)/818.5(2) pm, β = 110.48(2)°/110.53(2)°, R_all = 0.0341/0.0531) can be obtained from reactions of the oxides Sm₂O₃ and Gd₂O₃, respectively, with CuO and SeO₂. The crystal structure contains square planar [CuO₄] groups and irregular [MO₉] polyhedra.     

Synthesis and crystal structure of new sodium oxothiocyanofluoroantimonate(III) Na2Sb5F9O3(NCS)2

Na₂Sb₅F₉O₃(NCS)₂, a new complex, has been synthesized from NaSCN and SbF₃ aqueous solutions and studied by chemical, X-ray diffraction, and thermal analyses and IR, ^121,123Sb NQR, and ¹⁹F NMR spectroscopy. Its layered structure (triclinic symmetry system, a = 6.9998(1) Å, b = 9.4180(1) Å, c = 13.1094(2) Å, α = 74.815(1)°, β = 78.188(1)°, γ = 82.779(1)°, Z = 2, space group P $\bar 1$ ) is built of Na⁺ cations and [Sb₁₀F₁₈O₆(NCS)₄]^4? decanuclear complex anions that consist of two [Sb₅F₉O₃(NCS)₂]^2? pentanuclear complex anions linked by two weak Sb-F ionic bonds (2.529(2) Å). Decanuclear complex anions are linked into layers by secondary Sb…F bonds and Na-F bonds. Van der Waals interactions link these layers into a framework. The complex is stable up to 200°C.     

Das erste Alkali-Erdalkali-Oxocuprat(II,III): NaBa2Cu22+Cu3+O6

The first Alkaline Alkaline-Earth Oxocuprate (II, III): NaBa₂Cu₂²⁺Cu³⁺O₆ The compound NaBa₂Cu₃O₆ was prepared by heating of Na₂O₂, BaO₂, Cu₂O in closed Ag-tubes. X-ray single crystal investigations led to orthorhombic symmetry, space group D-Fmmm; a = 8.4229; b = 11.4418; c = 14.4063 Å; Z = 8. Cu²⁺ and Cu³⁺ show square planar polygones of four and Na⁺ trigonal prisms of six O^2?. The two barium point positions show coordination numbers C.N. = 8 and 6 + 4. The crystal structure is discussed.     

New organic–inorganic hybrid structure based on paradodecatungstate clusters and imidazolium cations

An organic–inorganic hybrid material based on paradodecatungstate anions and imidazolium cations, Na₂(HIm)₈(H₂W₁₂O₄₂)·10H₂O (HIm: imidazolium), has been synthesized under mildly acidic conditions. This compound was characterized by single-crystal X-ray diffraction, IR and UV–visible spectroscopies, and thermogravimetric and differential thermal analyses. The compound crystallizes in the triclinic P-1 space group with a = 11.6945(8) Å, b = 12.4782(6) Å, c = 14.0952(9) Å, α = 106.041(3)°, β = 109.338(2)°, γ = 100.249(3)°, V = 1781.0(3) Å³, and Z = 2. The crystal structure exhibits an infinite 1D inorganic structure built from [H₂W₁₂O₄₂]^10? clusters and sodium cations; adjacent chains are further joined up by hydrogen-bonding interactions between protonated imidazole cations, water molecules, and polyoxoanions, to form a 3D supramolecular architecture.     

Ein Beitrag zur Kristallstruktur von CuYW2O8, CuHoW2O8 und CuYbW2O8

A Contribution on the Crystal Structure of CuYW₂O₈, CuHoW₂O₈, and CuYW₂O₈ Single crystals of (I) CuY₂O₈, (II), CuHoW₂O₈, and (III) CuYbW₂O₈ were prepared and investigated by X-ray technique. (I) crystallizes with triclinic symmetry, space group C? P1 (a = 5.939 Å, b = 6.042 Å, c = 5.025 Å; α = 112.30°, β = 111.77°; Z = 1). (II) and (III) belong to monoclinic symmetry, space group C? P2/n (II) (a = 10.045 Å, b = 5.808 Å, c = 5.021 Å; β = 94.38°; z = 2 (III) a = 9.948 Å, b = 5.824 Å, c = 5.008 Å; β = 93.36°; Z = 2). The crystal structures will be discussed with respect to other to copper rare earth tungstates.     

Synthesis and crystal structure of KBi(C6H4O7) · 3.5H2O

A novel compound, KBi(C₆H₄O₇) · 3.5H₂O (I), has been synthesized in the Bi(NO₃)₂-K₃(HCit) system (HCit^3? is an anion of citric acid C₆H₈O₇) at a component ratio (n) of 8 in a water-glycerol mixture, and its crystal structure has been determined. The crystals are unstable in air. The crystals are triclinic: a = 7.462 Å, b = 10.064 Å, c = 17.582 Å, α = 100.27°, β = 99.31°, γ = 105.48°, V = 1221.2 ų, Z = 2, space group $P\bar 1$ . In the structure of I, asymmetric binuclear fragments [Bi₂(Cit^4?)₂(H₂O)₂]^2? are linked through inversion centers into polymeric chain anions. Ions K⁺ and crystal water molecules are arranged in channels between the chains. The Bi(1)...Bi(2) distances in the binuclear fragment are 4.62 Å, and the Bi(1)...Bi(1) and Bi(2)...Bi(2) distances between bismuth atoms in the chain are 5.83 and 5.95 Å, respectively. The chains are linked through bridging oxygen atoms of the ligands Cit to form layers. In the centrosymmetric four-membered chelate ring Bi₂O₂ formed through Bi-O(Cit) bonds, the distances Bi(1)-Bi(1) are equal to 4.55 Å, and Bi(1)-O are 2.66 and 2.84 Å. The Bi-O bond lengths in I are in the range 2.12–3.16 Å. The Cit ligands act as hexadentate chelating/bridging ligands.     

Synthese und Struktur des ersten ternären Blei(II)-Oxocuprats(I): PbCu2O2

Synthesis and Structure of the First Ternary Lead(II) Copper(I) Oxide: PbCu₂O₂ PbCu₂O₂ can be prepared by solid state reaction or by precipitation from a basic aqueous solution. Single crystals of the new compound were prepared by recrystallisation from a molten mixture (PbO? Cu₂O) and investigated by X-ray diffractometer technique. PbCu₂O₂ crystallizes isotypically with the homologue silver compound PbAg₂O₂ (monoclinic with a = 8.22₃ Å, b = 8.28₉ Å, c = 6.01₅ Å, β = 132.6₂°, Z = 4, space group C? C 1 2/c 1). The crystallographic data from the X-ray investigation are reported. The structure is built by endless [PbO_4/4]- and [CuO_2/4]-chains. Pb²⁺ has a one-sided asymmetric coordination with four next oxygen neighbours and Cu⁺ forms a stretched dumbbell with two oxygen atoms.     

Synthesis,Crystal Structure and Characterization of the Copper Iron Phosphate Cu8Fe2O5(PO4)4

The system CuO‐Fe₂O₃‐P₂O₅ has been investigated by means of the solid state reaction between CuO, Fe₂O₃ and (NH₄)₂HPO₄ in quartz crucibles at 900 °C. The powder samples were characterized by X‐ray diffraction, IR spectroscopy and TG/DTA. Single crystals of a new quaternary phase Cu₈Fe₂P₄O₂₁ were achieved by cooling from the melt of the compound in a sealed, evacuated quartz ampoule. Cu₈Fe₂O₅(PO₄)₄ crystallizes in the monoclinic space group C2/m (No 12) with a = 15.9733(8) Å, b = 5.9438(3) Å, c = 9.5530(5) Å, β = 113.76(1)°, Z = 2. The three‐dimensional framework consists of [FeO₆] octahedra, three different [CuO₅] polyhedra and [PO₄] tetrahedra. Cu₈Fe₂P₄O₂₁ exhibits an incongruently melting point at 945 °C.     

Synthesis of 1,2,4,5‐Benzenetetrasulfonic Acid (H4B4S) and its Implementation as a Linker for Building Metal‐Organic Frameworks on the Example of [Cu2(B4S)(H2O)8]·0.5H2O

Benzene 1,2,4,5‐tetrasulfonic acid (H₄B4S) was prepared in two steps starting from 1,2,4,5‐Tetrachlorobenzene. Slow evaporation of an aqueous reaction mixture of H₄B4S and Cu₂(OH)₂(CO₃) led to light green single crystals of [Cu₂(B4S)(H₂O)₈] · 0.5H₂O. X‐ray single crystal investigations revealed the compound to be triclinic [P , Z = 1, a = 710.0(1), b = 713.7(1), c = 1077.1(2) pm, α = 98.41(2)°, β = 102.91(2)°, γ = 100.69(2)°]. In the crystal structure the Cu²⁺ ions are coordinated by four water molecules and two monodentate sulfonate anions yielding a tetragonally distorted [CuO₆] octahedron. The anions are connected to further copper ions leading to ladder shaped chains running along the [100] direction. According to DTA/TG investigations the dehydration of the compound is finished at 240 °C and the decomposition of the anhydrous sulfonate starts at 340 °C.     

Mixed Valence Tungsten(IV,V) Compounds with Layered Structures (Part II)): Synthesis and Crystal Structures of Cu1−x[W2O2Cl6] and Cu1−x[W4O4Cl10]

The reaction of CuCl with WOCl₃ at 400 °C leads to a mixture of Cu_1?x[W₂O₂Cl₆] ( 1 ) and Cu_1?x[W₄O₄Cl₁₀] ( 2 ) in form of black lustrous needles. Both compounds crystallize in space group C2/m with a = 12.7832(5) Å, b = 3.7656(2) Å, c = 10.7362(3) Å, β = 119.169(2)° for 1 and a = 12.8367(19) Å, b = 3.7715(7) Å, c = 15.955(3) Å, β = 102.736(5)° for 2 . The structures are made up of WO₂Cl₄ octahedra. In the case of 1 two octahedra are edge‐sharing via chlorine atoms to form pairs which are linked via the trans‐positioned oxygen atoms to form infinite double strands . In the structure of 2 two of these double strands are condensed via terminal chlorine atoms to form quadruple strands . Like for all members of the M_x[W₂O₂X₆] structure family (X = Cl, Br) nonstochiometry with respect to the cations M was observed. The copper content of 1 and 2 was derived from the site occupation factors of the respective structure refinements. For several crystals examined the copper content varied between x = 0.27 and 0.17 for 1 and x = 0.04 for 2 . In both structures the oxochlorotungstate strands are negatively charged and connected to layers by the monovalent copper ions, which are tetrahedrally coordinated by the non‐bridging chlorine atoms of the strands. The structure models imply disorder of the Cu⁺ ions over closely neighboured sites.     

Crystal and molecular structure of guanidinium dicitratoferrate(II)

Synthesis and X-ray investigation of a (GunH)₂[Fe(Cit)₂] single crystal are described [a = 10.327(2) Å, b = 10.414(2) Å, c = 11.267(2) Å; β = 117.25(3)°, V = 1077.2(4) ų, P2₁/n, Z = 2, R(F) = 0,0239, 1196 reflections with I > 2σ(I )], where GunH is the guanidine cation (C(NH₂)₃)⁺, and Cit is the citric acid anion (C₆H₆O₇)^2?. The structure is composed of guanidinium cations and centrosymmetrical sym-cis-octahedral complex anions [Fe(Cit)₂]^2?. The Cit^2? anion acts as a cyclic tridentate ligand and forms condensed fiveand six-membered metal-containing cycles.     

Synthesis and study of ammonium decamolybdodimetallates

Ammonium decamolybdodimetallates (NH₄)_n[M₂Mo₁₀O₃₄(OH)₄] · 7H₂O, where M = Cr³⁺ (n = 6), Cu²⁺ (n = 8), or Ni²⁺ (n = 8), were synthesized for the first time and studied by X-ray diffraction, thermogravimetry, and IR spectroscopy. The compounds crystallize in the triclinic system with the following unit cell parameters: a = 10.68(2) Å, b = 9.46(2) Å, c = 7.97(2) Å, α = 75.12(3)°, β = 96.82(3)°, γ = 102.21(3)°, V = 754.4(3) ų, ρ_calcd = 4.05 g/cm³, Z = 1 for the chromium compound; and a = 10.57(2) Å, b = 9.29(2) Å, c = 8.47(2) Å, α = 73.91(3)°, β = 96.05(3)°, γ = 104.71(3)°, V = 854.3(3) ų, ρ_calcd = 3.68 g/cm³, Z = 1 (for the copper compound); and a = 10.96(2) Å, b = 8.95(2) Å, c = 7.40(2) Å, α = 71.76(3)°, β = 97.04(3)°, γ = 102.91(3)°, V = 875.3(3)ų, ρ_calcd = 3.65 g/cm₃, Z = 1 for the nickel compound.