The basic structure units of n are HgS 4 tetrahedra (point group symmetry. Methanol is generated during the gelling process of the silicate-based material according to the idealized reaction (H 3CO) 4Si + 4 H 2O → 4 H 4SiO 4 + 4 H 3COH and then becomes part of the crystal structure. In an attempt to grow crystals of the desired compound NiHg(SCN) 4 using a gel-growth method (Henisch, 1996), starting from TMOS (tetramethoxysilane) as gelling agent, we obtained the title compound, n viz. The crystal structure of NiHg(SCN) 4 has not been reported up to now, and only the structures of the related hydrous phase n (Porai Koshits, 1960) and of the mercury-richer phase NiHg 2(SCN) 6 (Iizuka, 1978) have been determined. Most of the MHg(SCN) 4 compounds have been structurally characterized, including MnHg(SCN) 4, FeHg(SCN) 4 (Yan et al., 1999), CoHg(SCN) 4 (Jeffery & Rose, 1968), CuHg(SCN) 4 (Porai Koshits, 1963 Khandar et al., 2011), ZnHg(SCN) 4 (Xu et al., 1999) and CdHg(SCN) 4 (Iizuka & Sudo, 1968). For example, CoHg(SCN) 4 is a calibrant for magnetic susceptibility measurements using the Faraday method (Brown et al., 1977), and representatives with M = Fe, Mn, Zn and Cd show second-order non-linear optical (NLO) properties (Bergman et al., 1970 Yan et al., 1999). H atoms treated by a mixture of independent and constrained refinementĬomputer programs: APEX2 and SAINT (Bruker, 2008 ), SHELXS97 and SHELXL97 (Sheldrick, 2008 ) and ATOMS for Windows (Dowty, 2006 ).Ĭompounds of the type MHg(SCN) 4 ( M is a divalent transition metal) exhibit interesting physical properties. of measured, independent and observed reflections Moreover, there is only a weak hydrogen-bonding interaction to an adjacent S atom that stabilizes this arrangement (Table 2 ). Thus the displacement ellipsoids of the methanol O and especially of the C atom are enlarged (Fig. 1 ). The methanol molecule has relatively much space for libration, because it is not part of the framework structure and points into the remaining free space. The displacement parameters of the methanol molecule are rather high. The trans-NiN 4O 2 octahedra are defined by four N atoms belonging to four bridging thiocyanate anions and by two O atoms of isolated methanol molecules. The Hg-S bond lengths are in very good agreement compared with those of HgS 4 tetrahedra in the above-mentioned solvent-free MHg(SCN) 4 structures, which have a mean of 2.57 (5) Å. 2.) and trans-NiN 4O 2 octahedra (point group symmetry 2.) that are linked through the bridging thiocyanate anions into a three-dimensional framework structure (Fig. 1 ). In an attempt to grow crystals of the desired compound NiHg(SCN) 4 using a gel-growth method (Henisch, 1996 ), starting from TMOS (tetramethoxysilane) as gelling agent, we obtained the title compound, n viz. The crystal structure of NiHg(SCN) 4 has not been reported up to now, and only the structures of the related hydrous phase n (Porai Koshits, 1960 ) and of the mercury-richer phase NiHg 2(SCN) 6 (Iizuka, 1978 ) have been determined. Most of the MHg(SCN) 4 compounds have been structurally characterized, including MnHg(SCN) 4, FeHg(SCN) 4 (Yan et al., 1999 ), CoHg(SCN) 4 (Jeffery & Rose, 1968 ), CuHg(SCN) 4 (Porai Koshits, 1963 Khandar et al., 2011 ), ZnHg(SCN) 4 (Xu et al., 1999 ) and CdHg(SCN) 4 (Iizuka & Sudo, 1968 ).
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