Acetatomercury(II) nitrate-mercury(II) acetate (llI), (AcOHg)
N03 • Hg(AOch, not described so far in the chemical literature,\u27
was obtained by the reaction of mercury(II) nit rate hydrate with
acetic anhydride. Orthorhombic-disphenoidal crystals, as shown
by threedimensional X-ray diffraction analysis, are built of polymeric
[AcOHg]nn+cations, nitrate anions and mercury(II)-acetate
molecules. The mercury ions in the cation are bridged over by the
acetate ion through both oxygen atom s separately at the Hg-O
distances of 213(3) and 212(2) pm under the O-Hg-O arigle of
167(1)°. The mercury(II)-acetate molecule is in syn. conformation
with the Hg-O distances of 204(3) and 209(3) pm and the
O-Hg-O angle of 173(1)°. Crystal structure, determined from
1330 intensity data, was refined by full-rnatrix least-squares
method to R = 0.076 and Rw = 0.090

Branka Korpar-Čolig

Drago Grdenić

Milan Sikirica

English

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CROATICA CHEMICA ACTA CCACAA 62 (1) 27-32 (1989)CCA-1835YU ISSN 0011-1643UDC 544.64Original Scientific PaperThe Endless Chain [AcOHg]:+ Cation. Crystal Structure ofAcetatomercury(II) Nitrate - Mercury(II) Acetate (111)Drago Grdenić, Milan Sikirica, and Branka K01'par-ČoligLaboratory of General and Ino1'ganic Chemistry, FacuLty of Science, Universityof Zagreb, P. O. Box 153, 41001 Zagreb, YugoslaviaReceived March 24, 1983Acetatomercury(II) nitrate-mercury(II) acetate (llI), (AcOHg)N03 • Hg(AOch, not described so far in the chemical literature,'was obtained by the reaction of mercury(II) nit rate hydrate withacetic anhydride. Orthorhombic-disphenoidal crystals, as shownby threedimensional X-ray diffraction analysis, are built of poly-meric [AcOHg]nn+cations, nitrate anions and mercury(II)-acetatemolecules. The mercury ions in the cation are bridged over by theacetate ion through both oxygen atom s separately at the Hg-Odistances of 213(3) and 212(2) pm under the O-Hg-O arigle of167(1)°. The mercury(II)-acetate molecule is in syn. conformationwith the Hg-O distances of 204(3) and 209(3) pm and theO-Hg-O angle of 173(1)°. Crystal structure, determined from1330 intensity data, was refined by full-rnatrix least-squaresmethod to R = 0.076 and Rw = 0.090.INTRODUCTIONWhen mercury(II) acetate is he at ed in acetic anhydride a condensationpolymer of trimercurated acetic acid is obtained.' When mercury(II) nitrateis used, instead of acetate, mercurated acetic acid is obtained" whose struc-ture has not been determined yet. Very likely it belongs to the nitrates oftrimercurated acetic acid." But, when mercuric nitrate hydrate, Hg(N03h . H,O,is added to acetic anhydride at room temperature, bright transparent cry-stals are separated from the solution immediately after a part of mercury(II)nitrate has been disolved. The separation of crystals proceeds in this wayuntil all mercury(II) nitrate added has been consumed. The separation ofthe crystals is accompanied by the evolution of nitrogen dioxide. Aceticanhydride has not been mercurated in this reaction, since the crystals testedwith aqueous sodium hydroxide give abundant precipitate of mercury(II)oxide. The composition of the crystals, according to chemical analysis, isdefined by the formula Hg2N03(OAchThe acetate ion in the product obviously resulted from the hydrolysisof acetic anhydride by water of the hydrated mercury(II) nitrate which wasused. Nitrogen dioxide appeared as the decomposition product of nitric acidset free by the action of acetic acid on mercury(II) nitrate in the nonaqueousmedium. The proper formula of the new salt, (AcOHg)N03• Hg(OAch, was28 D. GRDENIC ET AL.found from its crystal structure determined by X-ray diffraction analysis.It is an addition compound of mercury(IT) acetate with acetatomercury(II)nit rate containing polymeric [AcOHglnn+ cation which has not been reportedso Iar.!EXPERIMENTALPreparationThe compound (AcOHg)N03' Hg(OAch was prepared by dissolving Hg(N 03)2'.H20 in (i) acetic anhydride or (ii) in a mixture of glacial acetic acid with aceticanhydride.(i) l\IIercury(II) nit rate monohydrate (1 g), finely ground, was added in smallportions to acetic anhydride (10 ml) and the mixture was left for ONe hour atroom temperature with occasional shaking. The solid was filtered off, washedwith carbon tetrachloride and dried in vacuo. Yield: 0.84 g (89 0/0). AnaL Calcd.for C6H9Hg2N09 (M, = 640.32): C 11.26, H 1.42, Hg 62.65010; found: C 11.33, H 1.37,Hg 62.64010.(ii) l\IIercury(II) nitrate monohydrate (3.34 g), finely ground, was added inportions to a mixture of glacial acetic acid (6 ml) and acetic anhydride (1.3 ml)and the mixture was gently heated (- 50 DC) until complete dissolution of thenitrate and appearance of crystalline precipitate. After the mixture was leftfor one hour at room temperature, the solid was isolated as described above.Yield: 2.54 g (79010). AnaL Found: C 11.32, H 1.50, Hg 62.61010.X-Ray Diffraction AnalysisCrystal data were deterrnined with a Philips PW 1100 computer controlleddiffractometer (graphite monochromatized Mo-Ko. radiation, ,{= 71.07 pm),Single crystal data. - C6H9Hg2N09, mol. wt, 640.32, orthorhombic-dispheno-idal, space group P212121 with Z = 4 formula un its in the unit cell of dimensionsa = 1741.5(9), b = 872.9(8), c = 825.4(5) pm, V = 1.254 nm", Do = 3.26 Mg m", D, === 3.39 Mg m", F(OOO) = 1136, Ih (Mo-Ka) = 250.0 cm-I, crystal dimensions (mmfrom centroid): (Oll), (Oli) , (011\ (011) 0.130; (100), (100) 0.090; maximum andminimum transmission coefficients, 0.080 and 0.015.Intensity measurements. - Integrated intensities of 1330 reflections withI> 50 (I) were collected within the interval of 20 < 6 < 30° using the w - 26sean technique, with sean range 1.2CJ and scan rate 0.04 S-l. Correction for theabsorption," Lorentz and polarization effects were applied.Determination and refinement of the structure. - The structure was solverlby means of three-dimensional Fourier synthesis based upon the mercury atomcoordinates obtained from the Patterson synthesis and then refined by the full--matrix least-squares method. Weigbts of liCe; Fo) were alloted to 1324 reflections.The anisotropic temperature factors were assigned to the mercury atoms. Theatornic scattering factors were those of Cromer and Mann" with corrections forthe real and Imaginary parts of the anomalous dispersion for the mercury atomonly." The final values of the reliability indices were R = 0.076 and Rw = 0.090.The final values of the atomic coorđinates and thcrmal parameters with e. s. d'sare listed in Table I. Calculations were carried out on the UNIVAC llOO of SRCE,The University Computing Centre, Zagreb, using the XRA Y System."RESULTS AND DISCUSSIONThe correct formula (AcOHg)N03 • Hg(OAc)2 of the compound was obta-ined as the result of the X-ray crystal structure analysis. It excluded theformula Hg(N03h . 3Hg(OAc)2, which was first supposed on the basis of thechemical composition and properties. Therefore, the formation of the corn-pound by the reaction of mercury(II) nitrate monohydrate with acetic anhy-dride at room temperature is rep resen ted by the overall equation:ENDLESS ACETATOMERCURY(II) CATION 292 Hg(N03h' H20 + 3.5 OAC2-~ (AcOHg)N03' Hg(OAch + 3 N02 + 0.75 O2 + 4 HOAc.Nitrogen dioxide and oxygen, as the reaction products, were proved quanti-tatively: from the gas evolved, nitrogen dioxide was separated by conden-sation in a U-tube cooled in a mixture of ice and salt, the remaining oxygenwas identified by means of a glowing chip of wood." Accordingly, only oneof four moles of the nitrate ion, brought into the reaction, entered into thecomposition of the product. Nitric acid, formed by the reaction with nitrate(three of the four moles) with acetic acid, decomposed to nitrogen dioxide,oxygen and water. It follows that, in the given conditions, the nitrate ionis displaced from its compound with mercury by the acetate ion. Even thenitrate ion contained in the product is not bound to mercury but, as adiscrete anion, belongs only to its effective coordination.t"Descržptžon of the Structure. The crystal structure of (AcOHg)N03'. Hg(OAc)2, projected along the b-axis direction, is shown in Figure 1. Theinteratomic distances and bond angles are given in Table II. The crystalstructure is built up of three distinct components: the [AcOHgjlln+cation, thenitrate ani on and the mercury(II)-acetate molecule.Figure 1. The structure ef acetatomercury(II) nitrate - mercury (II) acetate (1/1),viewed along the b-axis direction.The [AcOHgjnn+cation is an endless chain in which the -OC(CH3)OHg-unit is repeated along the c-axis direction by the 21 symmetry operation.In other words, the mercury(II) cations, Hg(2), are bridged over by the ace-30 D. GRDENIĆ ET AL.TABLE IAtomie eoordinates and thermal parameters (pm" X 104) with estimated standarddeviations in parenthesesAtom U 01' Ucqx]aHg(l)Hg(2)N0(1)0(2)0(3)C(l1)C(12)0(11)0(12)C(21)C(22)0(21)0(22)C(31)C(32)0(31)0(32)H(121)H(122)H(123)H(221)H(222)H(223)H(321)H(322)H(323)ul»------------------------------.1175(2).4120(2).2329(38).1545(36).1720(40).3793(43).1039(52).0641(57).0325(36).2322(34).2760(45).3506(71).1800(33).3296(38).4035(69).3653(62).3347(32).4899(28).091.121.046.453.288.304.440.280.301.0808(1).3051(1).4347(16).4897(16).3732(17).4394(17).1705(22).1993(27).1215(16).1943(15).0698(21).0359(32).0307(15).1333(15).3204(28).3426(27).3536(14).2632(11).163.246.204.026-.020.065.343.309.305zle.7880(2).5332(2).3346(42).3387(39).4263(45).4039(45).5150(55).3455(67).5744(41).5760(38).0797(53).2277(80).0088(38).0345(47).8700(74)1.0485(71).7551(36).8472(29).272.330.350.233.237.3221.1071.1041.046.048(0)".039(0)".043(7).057(8).066(9).069(9).053(10).070(13).057(8).057(7).047(9).085(17).054(7).063(8).069(13).067(13).047(6).032(5)n Equivalent isotropic thermal parameters:Ucq = (1/6n2) Li Lj (3jj aj . bjtate ion with its oxygen atoms 0(31) and 0(32) linked separately each toone mercury atom. The Hg--O distances of 213(3) and 212(2) pm, respectively,are close to the sum of the covalent radii." Such a bridging of mercurycations by the acetate anion has not been observed so faro It is analogousto the ... 0C(CH3)OH ... bridging in the crystal structure of acetic acid,'!where hydrogen stands for mercury. The ·-0C(CH3)OHg-- chain belongs tothe composite connections in which the joining ligand is a group of atoms.PSuch connections are known in the structure of mercury(II) chromate-" andmercury(II) chromate hernihydr ate-! and, in a broader sense.P in the struc-ture of mercury(II) sulphate" and phosphate.l" The bond angles at the 0(31)and 0(32) oxygen atoms in the --0C(CH3)OHg-- chain are in syn and antiorientation, alternatively, and the chain has a zig-zag conformation like the--OHg-- chain in the orthorhombic mercuric oxide."? The more so since the--OC(CH3)OHg- chain is actually a ribbon of approximately coplanar atomsin a plan nearly parallel to the (320) crystallographic plane.The nitrate ion, with the interatomic distances and bond angles (Table II)in agreement with the literature data, is coordinated to the Hg(2) mercuryatom as a bidentate ligand with the 0(2) and 0(3) oxygen atoms at a distanceENDLESS ACETATOMERCURY(JI) CATION 31TABLE IIInteratomic distances (pm) and bond angles e), with estimated standard deviationsin parenrheses*(a) DistancesHg(1)-0(11) 204(3) C(12)-H(123) 97Hg(1)-O(21)' 209(3) C(22)-H(221) 91Hg(2)-0(31) 213(3) C(22)-H(222) 112Hg(2)-0(32)II 212(2) C(22)-H(223) 101N-O(l) 124(4) C(32)-H(321) 81N-0(2) 124(4) C(32)-H(322) 105N-0(3) 129(5) C(32)-H(323) 107C(11)-C(12) 153(7) Hg(l) ... 0(1)'11 271(3)C(11)-0(11) 117(5) Hg(l) ... 0(1)'" 275(3)C(1l)-0(12) 130(5) Hg(l) ... 0(2)"1 289(4)C(21)-C(22) 151(8) Hg(l) ... 0(3)'V 293(3)C(21)-0(21) 123(5) Hg(l) ... 0(12) 282(3)C(21)-0(22) 126(5) Hg(1) ... 0(22)' 290(4)C(31)-C(32) 156(3) Hg(2) ... 0(22)" 250(3)C(31)-0(31) 126(7) Hg(2) ... 0(12) 251(3)C(31)-0(32) 126(6) Hg(2) ... 0(32) 278(2)C(12)-H(121) 91 Hg(2) ... 0(2) 256(3)C(12)-H(122) 95 Hg(2) ... 0(3) 259(3)(b) Angles0(11)-Hg(1)·-0(21) 173(1) 0(11)-C(11)-0(12) 122(4)0(31)-Hg(2)-0(32) 167(1) C(22)-C(21)-0(21) 118(4)0(1)-N-0(2) 121(3) C(22)-C(21)-0(22) 115(4)0(l)-N-0(3) 122(3) 0(21)-C(21)-0(22) 127(4)0(2)-N-0(3) 116(3) C(32)-C(31)-0(31) 120(5)C(J2)-C(l1)-0(11) 120(4) C(32)-C(31)-O(32) 118(5)C(12)-C(11)-0(12) 117(4) 0(31)-C(31)-O(32) 122(5)* Transformation of the asymmetric unit (x, s, z): (i) x, y, 1 + z; (ii) 0.5-x,1- y, z - 0.5; (iii) 0.5- x, -y, z + 0.5; (iv) x - 0.5, 0.5- y, 1-z; (v) O.5-x,1-y, z + 0.5.of 256(3) and 259(3), pm, respectively. These oxygen atoms belong also tothe coordination of the Hg(l) mercury atom in the molecule of mercury(II)acetate, at distances of 289(4) and 293(3) pm, and bind together these twocomponents of the structure. The oxygen atoms of the bridging acetate ionsin the chain cation are not involved in the contacts with the Hg(l) atom,the Hg(l) ... 0(32) and Hg(l) ... 0(31) distances of 457 and 512 pm, respec-tively, being considerably larger than the sum of the van der Waals radii.10,12The mercury(II)-acetate molecule appears in the structure in syn eon-formation in contrast to the anti conformation in the crystal structure ofHg(OAch.t8 The preference for the syn conformation is caused by the donorfunction of the 0(12) and 0(22) carboxyl oxygen atoms towards the Hg(2)mercury atom in the cation, realized at Hg ... O distances of 251(3) and 250(3)pm, respectively. There are also two intramolecular contacts of the 0(12)and 0(22)i carboxyl oxygen atoms of 282(3) and 290(4) pm, respectively. Thebond lengths and angles (Table II) in the acetate ion are in agreement withthe known data.t"32 D. GRDENIĆ ET AL.REFERENCE S1. D. G r den i ć, B. Kor par - Č'o 1i g, and M. S i kir i c a, J. OrganornetaLChern. 276 (1984) 1.2. J. E. Mar s h and R. de J. F 1 e m i n g Str u the r s, J. Chern. Soc. (1927)2658.3. D. G r den i ć, M. S i kir i c a, and D. Mat k o v i ć - C alo g o v i Ć, J. Orga-nornetaL Chern. 306 (1986) 1.4. D. G r den i ć and M. S i kir i c a, Abstracts of Cornrntmications at the FourthYugosLav-ItaLian CrystaL/ographic Conference, Bled, 31st May-3rd June, 1982.SuppLernent to the AnnuaL of the YugosLav Centre oj CrystaHography, 17 (1982)S120.5. S. Ha r k e m a, private communication, Department of Chemical Technology,Twente University of Technolcgy, Drienerlo, The Netherlands, 1979.6. D. T. Cro m e r and J. B. Man n, Acta Cryst. A24 (1968) 321.7. D. T. Cro m e r and D. L i b e r man n, J. Chern. Ptius, 53 (1970) 1891.8. J. M. Ste war t, G. J. Kr u g e r, H. L. Am m o n, C. Di c k i n s o n, andS. R. Hall, The XRAY System - Version of June 1972. Tech. Rep. TR-192.Computer Science Centre, Univ. of Maryland, College Park, Maryland.9. J. R. Par t i n g t o n, A Text-Book of Inorganic Chernistry, 6th Edition, Mac-Millan and Co. Ltd., London, 1957, p. 553.10. D. G r den i Ć, Quart. Rev. 19 (1965) 303.11. E. J o n e s and D. H. Te m p 1 eto n, Acta Cryst. 11 (1958) 484.12. D. G r den i Ć, Connections in the CrystaL Structures of Mercury Cornpounds,in D. Do d s o n, J. P. G 1 u s k e r, and D. Sa y r e (Eds.), StructumL Studiesof MoLecuLes of BioLogicaL Interest, a Volume in Honour of Professor DorothyHodgkin, Clarendon Press, Oxford, 1981, p. 207.13. C. S t al han dsk e, Acta Cryst. B34 (1978) 1968.14. K. A u r i v i Il i u s and C. St a 1 han dsk e, Z. KristaHogr. 142 (1975) 129.15. A. B o nef ači Ć, Croat. Chern. Acta 35 (1963) 195.16. K. A u r i v i l l i u s and B. A. N i 1 s e n, Z. Kristal!ogr. 141 (1975) 1.17. K. A u r i v i Il i u s, Acta Chern. Scand. 18 (1964) 1552.18. R. All man n, Z. KristaHogr. 138 (1973) 336.SAŽETAKBeskonačni lančasti kati on [AcOHg]nn+.Krtstalna struktura acetatoživa(II)-nitrata--živa{II)-acetata (1/1)D. Grdenić, M. Sikirica i B. Korpar-ČoLigAcetatoživa(II)-nitrat-živa(II)-acetat (ljl), (AcOHg)N03' Hg(OAch, do sada .ne-poznat u kemijskoj literaturi, dobi ven je reakcijom živa(II)-nitrat-hidrata s ace-tanhidridom. Trodimenzijskom rendgenskom difrakcijskom analizom ustanovljenoje da su rompsko-sfenoidalni kristali spoja građeni od polimernih kationa [AcOHg]nn+,nitratnih aniona i molekula živa(II)-acetata. Zivini ioni u kationu premošteni suacetatnim ionima preko oba kisikova atoma odjelito na razmacima Hg-O od 213(3)i 212(2) pm pod kutem O-Hg-O od 167(1)°. Molekula živa(II)-acetata ima syn--konformaciju, a veze Hg-O od 204(3) i 209(3) pm čine kut O-Hg-O od 173(1)°.Kristalna struktura, određena na temelju izmjerenih intenziteta 1330 refleksa, utoč-njena je metodom najmanjih kvadrata s potpunom matricom do indeksa R = 0,076i Rw = 0,090.

The Endless Chain [AcOHg]nn+ Cation. Crystal Structure of Acetatomercury(II) Nitrate - Mercury(II) Acetate (1/1)

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CROATICA CHEMICA ACTA CCACAA 62 (1) 27-32 (1989)CCA-1835YU ISSN 0011-1643UDC 544.64Original Scientific PaperThe Endless Chain [AcOHg]:+ Cation. Crystal Structure ofAcetatomercury(II) Nitrate - Mercury(II) Acetate (111)Drago Grdenić, Milan Sikirica, and Branka K01'par-ČoligLaboratory of General and Ino1'ganic Chemistry, FacuLty of Science, Universityof Zagreb, P. O. Box 153, 41001 Zagreb, YugoslaviaReceived March 24, 1983Acetatomercury(II) nitrate-mercury(II) acetate (llI), (AcOHg)N03 • Hg(AOch, not described so far in the chemical literature,'was obtained by the reaction of mercury(II) nit rate hydrate withacetic anhydride. Orthorhombic-disphenoidal crystals, as shownby threedimensional X-ray diffraction analysis, are built of poly-meric [AcOHg]nn+cations, nitrate anions and mercury(II)-acetatemolecules. The mercury ions in the cation are bridged over by theacetate ion through both oxygen atom s separately at the Hg-Odistances of 213(3) and 212(2) pm under the O-Hg-O arigle of167(1)°. The mercury(II)-acetate molecule is in syn. conformationwith the Hg-O distances of 204(3) and 209(3) pm and theO-Hg-O angle of 173(1)°. Crystal structure, determined from1330 intensity data, was refined by full-rnatrix least-squaresmethod to R = 0.076 and Rw = 0.090.INTRODUCTIONWhen mercury(II) acetate is he at ed in acetic anhydride a condensationpolymer of trimercurated acetic acid is obtained.' When mercury(II) nitrateis used, instead of acetate, mercurated acetic acid is obtained" whose struc-ture has not been determined yet. Very likely it belongs to the nitrates oftrimercurated acetic acid." But, when mercuric nitrate hydrate, Hg(N03h . H,O,is added to acetic anhydride at room temperature, bright transparent cry-stals are separated from the solution immediately after a part of mercury(II)nitrate has been disolved. The separation of crystals proceeds in this wayuntil all mercury(II) nitrate added has been consumed. The separation ofthe crystals is accompanied by the evolution of nitrogen dioxide. Aceticanhydride has not been mercurated in this reaction, since the crystals testedwith aqueous sodium hydroxide give abundant precipitate of mercury(II)oxide. The composition of the crystals, according to chemical analysis, isdefined by the formula Hg2N03(OAchThe acetate ion in the product obviously resulted from the hydrolysisof acetic anhydride by water of the hydrated mercury(II) nitrate which wasused. Nitrogen dioxide appeared as the decomposition product of nitric acidset free by the action of acetic acid on mercury(II) nitrate in the nonaqueousmedium. The proper formula of the new salt, (AcOHg)N03• Hg(OAch, was28 D. GRDENIC ET AL.found from its crystal structure determined by X-ray diffraction analysis.It is an addition compound of mercury(IT) acetate with acetatomercury(II)nit rate containing polymeric [AcOHglnn+ cation which has not been reportedso Iar.!EXPERIMENTALPreparationThe compound (AcOHg)N03' Hg(OAch was prepared by dissolving Hg(N 03)2'.H20 in (i) acetic anhydride or (ii) in a mixture of glacial acetic acid with aceticanhydride.(i) l\IIercury(II) nit rate monohydrate (1 g), finely ground, was added in smallportions to acetic anhydride (10 ml) and the mixture was left for ONe hour atroom temperature with occasional shaking. The solid was filtered off, washedwith carbon tetrachloride and dried in vacuo. Yield: 0.84 g (89 0/0). AnaL Calcd.for C6H9Hg2N09 (M, = 640.32): C 11.26, H 1.42, Hg 62.65010; found: C 11.33, H 1.37,Hg 62.64010.(ii) l\IIercury(II) nitrate monohydrate (3.34 g), finely ground, was added inportions to a mixture of glacial acetic acid (6 ml) and acetic anhydride (1.3 ml)and the mixture was gently heated (- 50 DC) until complete dissolution of thenitrate and appearance of crystalline precipitate. After the mixture was leftfor one hour at room temperature, the solid was isolated as described above.Yield: 2.54 g (79010). AnaL Found: C 11.32, H 1.50, Hg 62.61010.X-Ray Diffraction AnalysisCrystal data were deterrnined with a Philips PW 1100 computer controlleddiffractometer (graphite monochromatized Mo-Ko. radiation, ,{= 71.07 pm),Single crystal data. - C6H9Hg2N09, mol. wt, 640.32, orthorhombic-dispheno-idal, space group P212121 with Z = 4 formula un its in the unit cell of dimensionsa = 1741.5(9), b = 872.9(8), c = 825.4(5) pm, V = 1.254 nm", Do = 3.26 Mg m", D, === 3.39 Mg m", F(OOO) = 1136, Ih (Mo-Ka) = 250.0 cm-I, crystal dimensions (mmfrom centroid): (Oll), (Oli) , (011\ (011) 0.130; (100), (100) 0.090; maximum andminimum transmission coefficients, 0.080 and 0.015.Intensity measurements. - Integrated intensities of 1330 reflections withI> 50 (I) were collected within the interval of 20 < 6 < 30° using the w - 26sean technique, with sean range 1.2CJ and scan rate 0.04 S-l. Correction for theabsorption," Lorentz and polarization effects were applied.Determination and refinement of the structure. - The structure was solverlby means of three-dimensional Fourier synthesis based upon the mercury atomcoordinates obtained from the Patterson synthesis and then refined by the full--matrix least-squares method. Weigbts of liCe; Fo) were alloted to 1324 reflections.The anisotropic temperature factors were assigned to the mercury atoms. Theatornic scattering factors were those of Cromer and Mann" with corrections forthe real and Imaginary parts of the anomalous dispersion for the mercury atomonly." The final values of the reliability indices were R = 0.076 and Rw = 0.090.The final values of the atomic coorđinates and thcrmal parameters with e. s. d'sare listed in Table I. Calculations were carried out on the UNIVAC llOO of SRCE,The University Computing Centre, Zagreb, using the XRAY System."RESULTS AND DISCUSSIONThe correct formula (AcOHg)N03 • Hg(OAc)2 of the compound was obta-ined as the result of the X-ray crystal structure analysis. It excluded theformula Hg(N03h . 3Hg(OAc)2, which was first supposed on the basis of thechemical composition and properties. Therefore, the formation of the corn-pound by the reaction of mercury(II) nitrate monohydrate with acetic anhy-dride at room temperature is rep resen ted by the overall equation:ENDLESS ACETATOMERCURY(II) CATION 292 Hg(N03h' H20 + 3.5 OAC2-~ (AcOHg)N03' Hg(OAch + 3 N02 + 0.75 O2 + 4 HOAc.Nitrogen dioxide and oxygen, as the reaction products, were proved quanti-tatively: from the gas evolved, nitrogen dioxide was separated by conden-sation in a U-tube cooled in a mixture of ice and salt, the remaining oxygenwas identified by means of a glowing chip of wood." Accordingly, only oneof four moles of the nitrate ion, brought into the reaction, entered into thecomposition of the product. Nitric acid, formed by the reaction with nitrate(three of the four moles) with acetic acid, decomposed to nitrogen dioxide,oxygen and water. It follows that, in the given conditions, the nitrate ionis displaced from its compound with mercury by the acetate ion. Even thenitrate ion contained in the product is not bound to mercury but, as adiscrete anion, belongs only to its effective coordination.t"Descržptžon of the Structure. The crystal structure of (AcOHg)N03'. Hg(OAc)2, projected along the b-axis direction, is shown in Figure 1. Theinteratomic distances and bond angles are given in Table II. The crystalstructure is built up of three distinct components: the [AcOHgjlln+cation, thenitrate ani on and the mercury(II)-acetate molecule.Figure 1. The structure ef acetatomercury(II) nitrate - mercury (II) acetate (1/1),viewed along the b-axis direction.The [AcOHgjnn+cation is an endless chain in which the -OC(CH3)OHg-unit is repeated along the c-axis direction by the 21 symmetry operation.In other words, the mercury(II) cations, Hg(2), are bridged over by the ace-30 D. GRDENIĆ ET AL.TABLE IAtomie eoordinates and thermal parameters (pm" X 104) with estimated standarddeviations in parenthesesAtom U 01' Ucqx]aHg(l)Hg(2)N0(1)0(2)0(3)C(l1)C(12)0(11)0(12)C(21)C(22)0(21)0(22)C(31)C(32)0(31)0(32)H(121)H(122)H(123)H(221)H(222)H(223)H(321)H(322)H(323)ul»------------------------------.1175(2).4120(2).2329(38).1545(36).1720(40).3793(43).1039(52).0641(57).0325(36).2322(34).2760(45).3506(71).1800(33).3296(38).4035(69).3653(62).3347(32).4899(28).091.121.046.453.288.304.440.280.301.0808(1).3051(1).4347(16).4897(16).3732(17).4394(17).1705(22).1993(27).1215(16).1943(15).0698(21).0359(32).0307(15).1333(15).3204(28).3426(27).3536(14).2632(11).163.246.204.026-.020.065.343.309.305zle.7880(2).5332(2).3346(42).3387(39).4263(45).4039(45).5150(55).3455(67).5744(41).5760(38).0797(53).2277(80).0088(38).0345(47).8700(74)1.0485(71).7551(36).8472(29).272.330.350.233.237.3221.1071.1041.046.048(0)".039(0)".043(7).057(8).066(9).069(9).053(10).070(13).057(8).057(7).047(9).085(17).054(7).063(8).069(13).067(13).047(6).032(5)n Equivalent isotropic thermal parameters:Ucq = (1/6n2) Li Lj (3jj aj . bjtate ion with its oxygen atoms 0(31) and 0(32) linked separately each toone mercury atom. The Hg--O distances of 213(3) and 212(2) pm, respectively,are close to the sum of the covalent radii." Such a bridging of mercurycations by the acetate anion has not been observed so faro It is analogousto the ... 0C(CH3)OH ... bridging in the crystal structure of acetic acid,'!where hydrogen stands for mercury. The ·-0C(CH3)OHg-- chain belongs tothe composite connections in which the joining ligand is a group of atoms.PSuch connections are known in the structure of mercury(II) chromate-" andmercury(II) chromate hernihydr ate-! and, in a broader sense.P in the struc-ture of mercury(II) sulphate" and phosphate.l" The bond angles at the 0(31)and 0(32) oxygen atoms in the --0C(CH3)OHg-- chain are in syn and antiorientation, alternatively, and the chain has a zig-zag conformation like the--OHg-- chain in the orthorhombic mercuric oxide."? The more so since the--OC(CH3)OHg- chain is actually a ribbon of approximately coplanar atomsin a plan nearly parallel to the (320) crystallographic plane.The nitrate ion, with the interatomic distances and bond angles (Table II)in agreement with the literature data, is coordinated to the Hg(2) mercuryatom as a bidentate ligand with the 0(2) and 0(3) oxygen atoms at a distanceENDLESS ACETATOMERCURY(JI) CATION 31TABLE IIInteratomic distances (pm) and bond angles e), with estimated standard deviationsin parenrheses*(a) DistancesHg(1)-0(11) 204(3) C(12)-H(123) 97Hg(1)-O(21)' 209(3) C(22)-H(221) 91Hg(2)-0(31) 213(3) C(22)-H(222) 112Hg(2)-0(32)II 212(2) C(22)-H(223) 101N-O(l) 124(4) C(32)-H(321) 81N-0(2) 124(4) C(32)-H(322) 105N-0(3) 129(5) C(32)-H(323) 107C(11)-C(12) 153(7) Hg(l) ... 0(1)'11 271(3)C(11)-0(11) 117(5) Hg(l) ... 0(1)'" 275(3)C(1l)-0(12) 130(5) Hg(l) ... 0(2)"1 289(4)C(21)-C(22) 151(8) Hg(l) ... 0(3)'V 293(3)C(21)-0(21) 123(5) Hg(l) ... 0(12) 282(3)C(21)-0(22) 126(5) Hg(1) ... 0(22)' 290(4)C(31)-C(32) 156(3) Hg(2) ... 0(22)" 250(3)C(31)-0(31) 126(7) Hg(2) ... 0(12) 251(3)C(31)-0(32) 126(6) Hg(2) ... 0(32) 278(2)C(12)-H(121) 91 Hg(2) ... 0(2) 256(3)C(12)-H(122) 95 Hg(2) ... 0(3) 259(3)(b) Angles0(11)-Hg(1)·-0(21) 173(1) 0(11)-C(11)-0(12) 122(4)0(31)-Hg(2)-0(32) 167(1) C(22)-C(21)-0(21) 118(4)0(1)-N-0(2) 121(3) C(22)-C(21)-0(22) 115(4)0(l)-N-0(3) 122(3) 0(21)-C(21)-0(22) 127(4)0(2)-N-0(3) 116(3) C(32)-C(31)-0(31) 120(5)C(J2)-C(l1)-0(11) 120(4) C(32)-C(31)-O(32) 118(5)C(12)-C(11)-0(12) 117(4) 0(31)-C(31)-O(32) 122(5)* Transformation of the asymmetric unit (x, s, z): (i) x, y, 1 + z; (ii) 0.5-x,1- y, z - 0.5; (iii) 0.5- x, -y, z + 0.5; (iv) x - 0.5, 0.5- y, 1-z; (v) O.5-x,1-y, z + 0.5.of 256(3) and 259(3), pm, respectively. These oxygen atoms belong also tothe coordination of the Hg(l) mercury atom in the molecule of mercury(II)acetate, at distances of 289(4) and 293(3) pm, and bind together these twocomponents of the structure. The oxygen atoms of the bridging acetate ionsin the chain cation are not involved in the contacts with the Hg(l) atom,the Hg(l) ... 0(32) and Hg(l) ... 0(31) distances of 457 and 512 pm, respec-tively, being considerably larger than the sum of the van der Waals radii.10,12The mercury(II)-acetate molecule appears in the structure in syn eon-formation in contrast to the anti conformation in the crystal structure ofHg(OAch.t8 The preference for the syn conformation is caused by the donorfunction of the 0(12) and 0(22) carboxyl oxygen atoms towards the Hg(2)mercury atom in the cation, realized at Hg ... O distances of 251(3) and 250(3)pm, respectively. There are also two intramolecular contacts of the 0(12)and 0(22)i carboxyl oxygen atoms of 282(3) and 290(4) pm, respectively. Thebond lengths and angles (Table II) in the acetate ion are in agreement withthe known data.t"32 D. GRDENIĆ ET AL.REFERENCE S1. D. G r den i ć, B. Kor par - Č'o 1i g, and M. S i kir i c a, J. OrganornetaLChern. 276 (1984) 1.2. J. E. Mar s h and R. de J. F 1e m i n g Str u the r s, J. Chern. Soc. (1927)2658.3. D. G r den i ć, M. S i kir i c a, and D. Mat k o v i ć - C alo g o v i Ć, J. Orga-nornetaL Chern. 306 (1986) 1.4. D. G r den i ć and M. S i kir i c a, Abstracts of Cornrntmications at the FourthYugosLav-ItaLian CrystaL/ographic Conference, Bled, 31st May-3rd June, 1982.SuppLernent to the AnnuaL of the YugosLav Centre oj CrystaHography, 17 (1982)S120.5. S. Ha r k e m a, private communication, Department of Chemical Technology,Twente University of Technolcgy, Drienerlo, The Netherlands, 1979.6. D. T. Cro m e r and J. B. Man n, Acta Cryst. A24 (1968) 321.7. D. T. Cro m e r and D. L i b e r man n, J. Chern. Ptius, 53 (1970) 1891.8. J. M. Ste war t, G. J. Kr u g e r, H. L. Am m o n, C. Di c k i n s o n, andS. R. Hall, The XRAY System - Version of June 1972. Tech. Rep. TR-192.Computer Science Centre, Univ. of Maryland, College Park, Maryland.9. J. R. Par t i n g t o n, A Text-Book of Inorganic Chernistry, 6th Edition, Mac-Millan and Co. Ltd., London, 1957, p. 553.10. D. G r den i Ć, Quart. Rev. 19 (1965) 303.11. E. J o n e s and D. H. Te m p 1eto n, Acta Cryst. 11 (1958) 484.12. D. G r den i Ć, Connections in the CrystaL Structures of Mercury Cornpounds,in D. Do d s o n, J. P. G 1u s k e r, and D. Sa y r e (Eds.), StructumL Studiesof MoLecuLes of BioLogicaL Interest, a Volume in Honour of Professor DorothyHodgkin, Clarendon Press, Oxford, 1981, p. 207.13. C. S t al han dsk e, Acta Cryst. B34 (1978) 1968.14. K. A u r i v i Il i u s and C. St a 1han dsk e, Z. KristaHogr. 142 (1975) 129.15. A. B o nef ači Ć, Croat. Chern. Acta 35 (1963) 195.16. K. A u r i v i l l i u s and B. A. N i 1s e n, Z. Kristal!ogr. 141 (1975) 1.17. K. A u r i v i Il i u s, Acta Chern. Scand. 18 (1964) 1552.18. R. All man n, Z. KristaHogr. 138 (1973) 336.SAŽETAKBeskonačni lančasti kati on [AcOHg]nn+.Krtstalna struktura acetatoživa(II)-nitrata--živa{II)-acetata (1/1)D. Grdenić, M. Sikirica i B. Korpar-ČoLigAcetatoživa(II)-nitrat-živa(II)-acetat (ljl), (AcOHg)N03' Hg(OAch, do sada .ne-poznat u kemijskoj literaturi, dobi ven je reakcijom živa(II)-nitrat-hidrata s ace-tanhidridom. Trodimenzijskom rendgenskom difrakcijskom analizom ustanovljenoje da su rompsko-sfenoidalni kristali spoja građeni od polimernih kationa [AcOHg]nn+,nitratnih aniona i molekula živa(II)-acetata. Zivini ioni u kationu premošteni suacetatnim ionima preko oba kisikova atoma odjelito na razmacima Hg-O od 213(3)i 212(2) pm pod kutem O-Hg-O od 167(1)°. Molekula živa(II)-acetata ima syn--konformaciju, a veze Hg-O od 204(3) i 209(3) pm čine kut O-Hg-O od 173(1)°.Kristalna struktura, određena na temelju izmjerenih intenziteta 1330 refleksa, utoč-njena je metodom najmanjih kvadrata s potpunom matricom do indeksa R = 0,076i Rw = 0,090.

The Endless Chain [AcOHg]nn+ Cation. Crystal Structure of Acetatomercury(II) Nitrate - Mercury(II) Acetate (1/1)

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