The Cd^{II} ion in the title complex, [Cd(SCN)_{2}{SC(NH_{2})_{2}}_{2}]_{}, is situated at a centre of symmetry, and is bound to two N atoms belonging to thiocyanate groups and to four S atoms of bridging thiourea ligands. The structure consists of infinite chains of slightly distorted edgeshared Cdcentred octahedra. The bridging S atoms of two thiourea ligands comprise the common edge. Some thermal properties are described.
Supporting information
CCDC reference: 188597
Cd(SCN)_{2} was prepared by the reaction of CdX_{2} (where X = Cl,
NO_{3} or CH_{3}COO) and ASCN (where A = K, Na or NH_{4}) (molar ratio 1:2) in
water. The crystalline powders of Cd(SCN)_{2} and thiourea were dissolved in
water in stoichiometric proportions at about 313 K. The mixture was left
standing at room temperature, from which the colorless crystals of BTCT used
for the Xray structure determination were obtained.
All H atoms were refined and N—H distances were in the range 0.81 (4)–0.92 (4) Å.
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL.
Crystal data top
[Cd(SCN)_{2}(CH_{4}N_{2}S)_{2}]  Z = 1 
M_{r} = 380.85  F(000) = 186 
Triclinic, P1  D_{x} = 2.099 Mg m^{−}^{3} 
Hall symbol: p 1  Mo Kα radiation, λ = 0.71073 Å 
a = 4.0368 (3) Å  Cell parameters from 37 reflections 
b = 7.7237 (4) Å  θ = 5.9–15.5° 
c = 10.1355 (5) Å  µ = 2.48 mm^{−}^{1} 
α = 84.607 (4)°  T = 293 K 
β = 80.825 (5)°  Prism, colourless 
γ = 75.318 (5)°  0.18 × 0.15 × 0.10 mm 
V = 301.31 (3) Å^{3}  
Data collection top
Bruker P4 diffractometer  1637 reflections with I > 2σ(I) 
Radiation source: finefocus sealed tube  R_{int} = 0.015 
Graphite monochromator  θ_{max} = 30.0°, θ_{min} = 2.0° 
θ/2θ scans  h = −1→5 
Absorption correction: ψ scan (XSCANS; Siemens, 1996)  k = −10→10 
T_{min} = 0.640, T_{max} = 0.782  l = −14→14 
2433 measured reflections  3 standard reflections every 97 reflections 
1757 independent reflections  intensity decay: none 
Refinement top
Refinement on F^{2}  Primary atom site location: structureinvariant direct methods 
Leastsquares matrix: full  Secondary atom site location: difference Fourier map 
R[F^{2} > 2σ(F^{2})] = 0.022  Hydrogen site location: inferred from neighbouring sites 
wR(F^{2}) = 0.065  All Hatom parameters refined 
S = 1.14  w = 1/[σ^{2}(F_{o}^{2}) + (0.0253P)^{2} + 0.1999P] where P = (F_{o}^{2} + 2F_{c}^{2})/3 
1757 reflections  (Δ/σ)_{max} < 0.001 
86 parameters  Δρ_{max} = 0.60 e Å^{−}^{3} 
0 restraints  Δρ_{min} = −0.66 e Å^{−}^{3} 
Crystal data top
[Cd(SCN)_{2}(CH_{4}N_{2}S)_{2}]  γ = 75.318 (5)° 
M_{r} = 380.85  V = 301.31 (3) Å^{3} 
Triclinic, P1  Z = 1 
a = 4.0368 (3) Å  Mo Kα radiation 
b = 7.7237 (4) Å  µ = 2.48 mm^{−}^{1} 
c = 10.1355 (5) Å  T = 293 K 
α = 84.607 (4)°  0.18 × 0.15 × 0.10 mm 
β = 80.825 (5)°  
Data collection top
Bruker P4 diffractometer  1637 reflections with I > 2σ(I) 
Absorption correction: ψ scan (XSCANS; Siemens, 1996)  R_{int} = 0.015 
T_{min} = 0.640, T_{max} = 0.782  3 standard reflections every 97 reflections 
2433 measured reflections  intensity decay: none 
1757 independent reflections  
Refinement top
R[F^{2} > 2σ(F^{2})] = 0.022  0 restraints 
wR(F^{2}) = 0.065  All Hatom parameters refined 
S = 1.14  Δρ_{max} = 0.60 e Å^{−}^{3} 
1757 reflections  Δρ_{min} = −0.66 e Å^{−}^{3} 
86 parameters  
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. 
Refinement. Refinement of F^{2} against ALL reflections. The weighted Rfactor
wR and goodness of fit S are based on F^{2}, conventional
Rfactors R are based on F, with F set to zero for
negative F^{2}. The threshold expression of F^{2} >
σ(F^{2}) is used only for calculating Rfactors(gt) etc.
and is not relevant to the choice of reflections for refinement.
Rfactors based on F^{2} are statistically about twice as large
as those based on F, and R factors based on ALL data will be
even larger. 
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å^{2}) top  x  y  z  U_{iso}*/U_{eq}  
Cd  1.0000  0.0000  0.0000  0.02530 (8)  
S2  0.38123 (14)  0.24618 (7)  0.03097 (5)  0.02272 (11)  
S1  1.28382 (19)  −0.29833 (11)  0.42963 (7)  0.04088 (17)  
N1  0.9855 (6)  −0.0947 (3)  0.2180 (2)  0.0327 (4)  
C2  0.2265 (6)  0.3052 (3)  0.1950 (2)  0.0249 (4)  
N2  0.3572 (7)  0.2102 (3)  0.2975 (2)  0.0359 (5)  
C1  1.1093 (6)  −0.1789 (3)  0.3062 (2)  0.0253 (4)  
N3  −0.0306 (7)  0.4492 (3)  0.2142 (3)  0.0398 (6)  
H2B  0.276 (10)  0.234 (5)  0.384 (4)  0.040 (9)*  
H2A  0.558 (11)  0.122 (5)  0.286 (4)  0.044 (10)*  
H3B  −0.095 (11)  0.490 (6)  0.287 (4)  0.052 (11)*  
H3A  −0.099 (13)  0.506 (7)  0.145 (5)  0.076 (15)*  
Atomic displacement parameters (Å^{2}) top  U^{11}  U^{22}  U^{33}  U^{12}  U^{13}  U^{23} 
Cd  0.02309 (12)  0.03219 (13)  0.01756 (11)  −0.00200 (9)  −0.00363 (8)  0.00240 (8) 
S2  0.0225 (2)  0.0235 (2)  0.0199 (2)  −0.0010 (2)  −0.00307 (19)  −0.00228 (18) 
S1  0.0326 (3)  0.0579 (4)  0.0249 (3)  0.0000 (3)  −0.0078 (2)  0.0103 (3) 
N1  0.0388 (11)  0.0361 (10)  0.0213 (9)  −0.0071 (9)  −0.0054 (8)  0.0042 (8) 
C2  0.0263 (10)  0.0244 (9)  0.0235 (10)  −0.0055 (8)  −0.0009 (8)  −0.0045 (7) 
N2  0.0431 (13)  0.0387 (11)  0.0220 (9)  −0.0013 (10)  −0.0055 (9)  −0.0039 (8) 
C1  0.0257 (10)  0.0291 (10)  0.0207 (9)  −0.0069 (8)  −0.0010 (8)  −0.0022 (8) 
N3  0.0459 (14)  0.0338 (11)  0.0296 (11)  0.0079 (10)  0.0009 (10)  −0.0097 (9) 
Geometric parameters (Å, º) top
Cd—N1  2.258 (2)  C2—N2  1.316 (3) 
Cd—S2  2.7217 (5)  C2—N3  1.320 (3) 
Cd—S2^{i}  2.7985 (6)  N2—H2B  0.90 (4) 
S2—C2  1.740 (2)  N2—H2A  0.92 (4) 
S1—C1  1.627 (2)  N3—H3B  0.81 (4) 
N1—C1  1.158 (3)  N3—H3A  0.84 (5) 
   
N1—Cd—S2  95.85 (6)  N2—C2—N3  120.4 (2) 
N1—Cd—S2^{ii}  84.15 (6)  N2—C2—S2  121.80 (19) 
N1—Cd—S2^{i}  88.28 (6)  N3—C2—S2  117.77 (19) 
S2—Cd—S2^{i}  86.023 (16)  C2—N2—H2B  124 (2) 
N1—Cd—S2^{iii}  91.72 (6)  C2—N2—H2A  122 (2) 
S2—Cd—S2^{iii}  93.977 (16)  H2B—N2—H2A  114 (3) 
C2—S2—Cd  114.67 (8)  N1—C1—S1  179.6 (2) 
C2—S2—Cd^{iv}  101.74 (8)  C2—N3—H3B  122 (3) 
Cd—S2—Cd^{iv}  93.977 (16)  C2—N3—H3A  116 (4) 
C1—N1—Cd  152.1 (2)  H3B—N3—H3A  121 (4) 
Symmetry codes: (i) −x+1, −y, −z; (ii) −x+2, −y, −z; (iii) x+1, y, z; (iv) x−1, y, z. 
Hydrogenbond geometry (Å, º) top
D—H···A  D—H  H···A  D···A  D—H···A 
N2—H2A···N1  0.92 (4)  2.15 (4)  3.051 (3)  166 (3) 
N2—H2B···S1^{v}  0.90 (4)  2.94 (4)  3.513 (3)  123 (3) 
N3—H3A···S2^{vi}  0.84 (5)  2.66 (5)  3.471 (3)  165 (5) 
Symmetry codes: (v) −x+2, −y, −z+1; (vi) −x, −y+1, −z. 
Experimental details
Crystal data 
Chemical formula  [Cd(SCN)_{2}(CH_{4}N_{2}S)_{2}] 
M_{r}  380.85 
Crystal system, space group  Triclinic, P1 
Temperature (K)  293 
a, b, c (Å)  4.0368 (3), 7.7237 (4), 10.1355 (5) 
α, β, γ (°)  84.607 (4), 80.825 (5), 75.318 (5) 
V (Å^{3})  301.31 (3) 
Z  1 
Radiation type  Mo Kα 
µ (mm^{−}^{1})  2.48 
Crystal size (mm)  0.18 × 0.15 × 0.10 

Data collection 
Diffractometer  Bruker P4 diffractometer 
Absorption correction  ψ scan (XSCANS; Siemens, 1996) 
T_{min}, T_{max}  0.640, 0.782 
No. of measured, independent and observed [I > 2σ(I)] reflections  2433, 1757, 1637 
R_{int}  0.015 
(sin θ/λ)_{max} (Å^{−}^{1})  0.703 

Refinement 
R[F^{2} > 2σ(F^{2})], wR(F^{2}), S  0.022, 0.065, 1.14 
No. of reflections  1757 
No. of parameters  86 
Hatom treatment  All Hatom parameters refined 
Δρ_{max}, Δρ_{min} (e Å^{−}^{3})  0.60, −0.66 
Selected geometric parameters (Å, º) topCd—N1  2.258 (2)  Cd—S2^{i}  2.7985 (6) 
Cd—S2  2.7217 (5)   
   
N1—Cd—S2  95.85 (6)  S2—Cd—S2^{i}  86.023 (16) 
N1—Cd—S2^{ii}  84.15 (6)  N1—Cd—S2^{iii}  91.72 (6) 
N1—Cd—S2^{i}  88.28 (6)  S2—Cd—S2^{iii}  93.977 (16) 
Symmetry codes: (i) −x+1, −y, −z; (ii) −x+2, −y, −z; (iii) x+1, y, z. 
Hydrogenbond geometry (Å, º) top
D—H···A  D—H  H···A  D···A  D—H···A 
N2—H2A···N1  0.92 (4)  2.15 (4)  3.051 (3)  166 (3) 
N2—H2B···S1^{iv}  0.90 (4)  2.94 (4)  3.513 (3)  123 (3) 
N3—H3A···S2^{v}  0.84 (5)  2.66 (5)  3.471 (3)  165 (5) 
Symmetry codes: (iv) −x+2, −y, −z+1; (v) −x, −y+1, −z. 
From a chemical and structural point of view, cadmium complexes have been extensively studied due to the ability of cadmium to adopt different modes of coordination determined by considerations of size, as well as electrostatic and covalent bonding forces. The presence of the thiocyanate (SCN^{}) ion as a ligand introduces some additional degrees of freedom, because of its versatility in acting as a monodentate, bidentate or bridging ligand. Recently, coordination compounds formed by thiourea and cadmium have received renewed attention (Alia et al., 1999). This interest arises for two main reasons: (I) the nonlinear optical (NLO) properties of these compounds (Yu et al., 2001) and (ii) the convenient preparation of semiconducting materials through the thermal decomposition of these complexes (Krunks et al., 1997; Semenov & Naumov, 2001). As part of these investigations, the title complex, catenapoly[[bis(thiocyanateκN)cadmium(II)]diµthioureaκ^{2}S:S] (abbreviated as BTCT, hereinafter), has been prepared and its thermal properties have been described.
The Cd^{II} atom, which is situated at a centre of symmetry, is bound to two thiocyanate N atoms and to four thiourea S atoms. The structure consists of infinite chains of edgeshared Cdcentred slightly distorted octahedra. The bridging S atoms of two thiourea ligands comprise the common edge. The Cd—S distances [2.7217 (5) and 2.7985 (6) Å] are much longer that the sum (2.52 Å) of the singlebond covalent radii (Pauling, 1960), indicating a relatively weak covalent interaction. The Cd—N bond lengths [2.258 (2) Å] are much shorter than the sum of Shannon's ionic radii (2.41 Å; Shannon, 1976), which is probably because the assumed valences of the N and S atoms are not appropriate, for the charges on the SCN^{} ions are delocalized. The N—Cd—S and S—Cd—S angles (between adjacent atoms) are in the ranges 84.15 (6)–95.85 (6) and 86.023 (16)–93.977 (16)°, respectively, which are somewhat different from the typical octahedral angles. The thermal decomposition results (under nitrogen flux) indicate that two thiourea molecules are lost initially; the decomposition of Cd(SCN)_{2} occurs subsequently, and the final product is CdS crystalline powder.