The crystal and molecular structure of strontium nitroprusside tetrahydrate

Abstract

Sr[Fe(CN)sNOI.4H20 crystallizes in the monoclinic system, space group C2/m, with a = 20.08 (2), b = 7.51 (4), c = 8-42 (2) ,~,, fl = 98-4 (3) °, Z = 4. The structure was solved by the heavy-atom method and refined by least squares to R = 0.099 for 1014 reflexions. The nitroprusside ion is in a special position with site symmetry m; the water molecules can be grouped into three categories according to their chemical environments: in one category the molecule is at the van der Waals distance from its inversion-symmetryrelated molecule and also strongly hydrogen-bonded to a molecule of the second category. The third type belongs to the octahedral environment of the Sr ion. The nitrosyi groups of neighbouring nitroprusside ions are approximately parallel to a and are piled up along e at intervals of about 4 A, a distance short enough to allow a strong dipole--dipole interaction which is perhaps responsible for the broadness of the NO stretching band. The [Fe(CN)sNO] 2-ions are highly distorted octahedra with a mean Fe-C distance of 1.94 and Fe-N of 1-64/~,.

Structural characterization of heteropolymeric iron and main group metal complexes

“…The inner coordination sphere about the M atoms are: MgN 4 O 2 (Johnson et al , 1991 ), CaN 4 O 2 (Mayer and Pichard , 1988 ) and CaO 7 (Cohen and Hoard , 1966 ;Pavelč í k and Kettmann, 1983 ); SrO 9 + SrO 10 (Burger and Kl ü fers, 1966b ), SrO 3 N 2 + SrO 8 (Meyer and Pickerdt , 1989 ), Sr 4 O 2 (Castellano et al , 1977 ) and SrN 5 ( H ö hn et al, 1991 ); BaO 8 (Burger and Kl ü fers, 1966a,b ;Calogero et al , 1977 ), BaO 3 N 3 + BaO 5 N 2 (Meyer and Pickerdt , 1989 ), BaN 5 ( H ö hn et al, 1991 ), BaO 5 N 4 + BaO 2 N 2 (Kl ü fers and Hauss ü l, 1985 ), BaN 5 O 4 (Navaza et al , 1990 ), BaO 11 (Solans et al , 1984b ) and BaO 9 (Chuklianova et al , 1981 ); InFe 4 (Che -Chieh et al, 1993 ), TlN 6 (Swartner et al , 1997 ), TlO 7 (Solans et al , 1984a ) and TlN 3 (Yukle et al , 1996 ); GeS 4 (Achak et al , 1996 ;Bowers et al , 1996 ;Akari et al , 1998 ), GeSe 4 (Akari et al , 1998 ); SnC 3 ON + SnC 3 N 2 (Adam et al , 1990 ;Behrens et al , 1991 ;Schwarz et al , 1996 ;Yian et al , 1996 ), SnC 3 O 2 (Graziani et al , 1980 ); BiCl 6 (Mammano et al , 1977 ), BiCl 2 Fe 2 (Enland et al , 1997 ), ZnC 4 Fe 2 (Pierpont et al , 1982 ), CdN 5 O (Mulliza et al , 1990 ), HgC 2 Fe 2 (Sosinski et al , 1983 ) and HgS 4 (Cingi et al , 1985 ).…”

“…Each Ca(II) atom has a cape trigonal prism arrangement, created by two O atoms of dcta ligand and fi ve O atoms of water molecules. (Burger and Kl ü fers, 1966b ;Castellano et al , 1977 ;Meyer and Pickerdt , 1989 ) and one FeSrLi ( H ö hn et al, 1991 ) derivative (Table 1 ). In yellow [Fe 4 (ara) 4 (OH) 2 Sr 4 (H 2 O) x ]CO 3 (Burger and Kl ü fers, 1966b ), the tetranuclear plane is built up from four edge-sharing FeO 6 octahedra by four tetradentate ara ligands and by the OH group.…”

“…In another red monoclinic (ON)Fe(CN) 5 Sr(H 2 O) 4 (Castellano et al , 1977 ), each Fe(III) is 6-coordinated (FeC 5 N) with the Fe-N (NO) bond distance of 1.64 (2) and Fe-C (CN) bond distance trans to the NO group of 1.97(2) . The remaining four Fe-C bond distances are equal: 1.93(2) .…”