644 [ThCI4(CH40)2(OH)2].C 10H2oO5.C 2H3N References ARTE, P. E., FENEAU-DUPONT,J., DECLERCQ,J.-P., GERMAIN, G. & VAN MEERSSCHE, M. (1979). Acta Cryst. B35, 1215-1220. BENNING,M. M. & ROGERS,R. D. (1987). Acta Cryst. A43, C181. DFAEAN,A., CHaaU, n% P., FOLCHER,G., RIGNY, P., NAVAZA,A. & TSOUCAmS, G. (1987). Polyhedron, 6, 189-195. International Tables for X-ray Crystallography (1974). Vol. IV, pp. 72, 99, 149. Birmingham: Kynoch Press. (Present distributor D. Reidel, Dordrecht.) JOHNSON, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA. NAV~ZA, A., VILLAIN, F. & CHA~rN, P. (1984). Polyhedron, 3, 143-149. ROGERS, R. D. (1987a). Acta Cryst. A43, C 181. ROGERS, R. D. (1987b). Inorg. Chim. Acta, 133, 347-352. ROGERS, R. D. (1988). Acta Cryst. C44, 638-641. ROGERS, R. D. & KURIHARA, L. K. (1987). Inorg. Chim.Acta, 129, 277-282. ROGERS, R. D., KURIHARA, L. K. & BENNING, M. M. (1987a). Acta Cryst. C43, 1056-1058. ROGERS, R. D., KURIHARA,L. K. & BENNING,M. M. (1987b). J. Inclusion Phenom. 5, 645-658. ROGERS, R. D., KURmARA, L. K. & BENNnSG,M. M. (1988). d. Chem. Soc. Dalton Trans. pp. 13-16. ROGERS, R. D., ROYAL, J. D. & BOLTON,D. M. (1987). d. Cryst. Spectrosc. Res. In the press. SHELDRICK, G. M. (1976). SHELX76. Program for crystal structure determination, locally modified. Univ. of Cambridge, England. VILLARDI, G. C. DE, CHARPIN, P., COSTES, R.-M., FOLCHER, G., PLUmEN, P., RmNY, P. & DE RANGO, C. (1978). J. Chem. Soc. Chem. Commun. pp. 90-92. Acta Cryst. (1988). C44, 644-646 Structure of Diaqua[ 1,6-bis(4-imidazolyl)-2,5-dithiahexane]nickel(II) Dinitrate BY ELISABETH BOUWMAN Department of Chemistry, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands JOHN S. WOOD* AND ROBERTA DAY Department of Chemistry, Lederle Graduate Research Center, University of Massachusetts, Amherst, MA 01003, USA AND J. CHRISTINE TEN HOVE, WILLEM L. DRIESSEN* AND JAN REEDLIK Department of Chemistry, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands (Received 27 October 1987; accepted 6 January 1988) Abstract. [Ni(C,oH14N4S2)(H20)21 (NO3)2, Mr= 473.12, triclinic, Pi, a = 10.305 (2), b = 10.483 (2), c = 10.791 (2) A, a= 62.46 (1), fl= 64.66 (1), ~- 65.22 (1) °, V= 897.9 (3) A 3, Z = 2, Dx= 1-750 g cm -a, 2(Mo Ka--)= 0.71073 ]k, p = 13.6 cm -1, F(000) = 448, T = 293 K, final R = 0.036 for 2666 observed reflections. The Ni n ion is octahedrally coordinated by two imidazole N atoms and two thioether S atoms of the ligand 1,6-bis(4-imidazolyl)- 2,5-dithiahexane, and two O atoms of coordinating water molecules. The Ni-N distances are 2.027 (3) and 2.050(3)A, the Ni-S distances 2.448(1) and 2.453 (1)A, and the Ni-O(aqua) distances 2.077 (2) and 2.084 (3)A. The non-coordinating nitrate ions are hydrogen-bonded to the nitrogen H atoms of the imidazole groups of the ligand and to the water molecules, forming chains of cations in the structure. * To whomcorrespondenceshouldbe addressed. 0108-2701/88/040644-03503.00 Introduction. Coordination compounds with imidazole- and thioether-contalning ligands are important as model systems for type I copper proteins. Recently a new method of synthesizing this kind of ligand has been developed (Bouwman & Driessen, 1988). One of the first ligands of this new series used in the preparation of coordination compounds is 1,6-bis(4-imidazolyl)-2,5- dithiahexane (bhdhx). The synthesis and characteriza- tion of several transition-metal compounds of bhdhx have been described recently (Bouwman, ten Hove, Driessen & Reedijk, 1988). The complexes with copper and nickel nitrates appeared to be X-ray isomorphous and the crystal structure of the copper compound [Cu(bhdhx)(NO3) 2] has been determined (Bouwman, ten Hove, Driessen & Reedijk, 1988). A second modification of the nickel nitrate compound has been crystallized, and shows Weissenberg photographs different from those of the copper nitrate compound. The crystal structure of this compound, with stoichiom- © 1988 International Union of Crystallography