Zinc cadmium seleno­cyanate

The crystal structure of a new bimetallic seleno­cyanate, zinc cadmium seleno­cyanate or poly[tetra-μ₂-seleno­cyanato-cadmium(II)zinc(II)], [ZnCd(SeCN)₄]_n, is an infinite three-dimensional network in which the slightly distorted CdSe₄ and ZnN₄ tetra­hedra are connected by –SeCN– bridges. The whole structure can be viewed as a diamondoid network with Cd and Zn nodes and –SeCN– spacers.

Key indicators

• Single-crystal X-ray study
• T = 291 K
• Mean [sigma](N-C) = 0.009 Å
• R factor = 0.033
• wR factor = 0.075
• Data-to-parameter ratio = 26.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT040_ALERT_1_C No H-atoms in this Carbon Containing Compound ..          ?
PLAT850_ALERT_2_C Check Flack Parameter Exact Value 0.00 and su ..       0.03

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           29.82
           From the CIF: _reflns_number_total                867
           Count of symmetry unique reflns          484
           Completeness (_total/calc)            179.13%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       383
           Fraction of Friedel pairs measured     0.791
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: XSCANS (Bruker,1996); cell refinement: XSCANS; data reduction: SHELXTL (Bruker, 1997); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

poly[tetra-µ₂-selenocyanato-cadmium(II)zinc(II)]

Crystal data

[ZnCd(SeCN)4]	Dx = 3.338 Mg m^−3
Mr = 597.69	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4	Cell parameters from 48 reflections
Hall symbol: I -4	θ = 5.1–15.7°
a = 11.3310 (6) Å	µ = 16.01 mm^−1
c = 4.6314 (8) Å	T = 291 K
V = 594.63 (11) Å^3	Prism, colourless
Z = 2	0.18 × 0.12 × 0.10 mm
F(000) = 532

Data collection

Bruker P4 diffractometer	801 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.014
Graphite monochromator	θmax = 29.8°, θmin = 2.5°
ω scans	h = −15→15
Absorption correction: multi-scan (XSCANS; Bruker, 1996)	k = −15→15
Tmin = 0.107, Tmax = 0.203	l = −6→6
2112 measured reflections	3 standard reflections every 97 reflections
867 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0301P)^2 + 4.6035P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.033	(Δ/σ)max < 0.001
wR(F^2) = 0.075	Δρmax = 0.54 e Å^−3
S = 1.09	Δρmin = −0.54 e Å^−3
867 reflections	Extinction correction: SHELXTL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
33 parameters	Extinction coefficient: 0.0079 (7)
0 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.00 (3)

Special details

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 F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² 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 (Ų)

	x	y	z	Uiso*/Ueq
Cd1	0.0000	0.0000	0.0000	0.0346 (3)
Zn1	0.0000	0.5000	0.2500	0.0330 (4)
Se1	−0.12213 (6)	0.15345 (6)	−0.31725 (16)	0.0369 (2)
N1	−0.0449 (5)	0.3641 (5)	0.0130 (17)	0.0398 (12)
C1	−0.0737 (6)	0.2820 (5)	−0.1120 (15)	0.0326 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.0283 (3)	0.0283 (3)	0.0471 (6)	0.000	0.000	0.000
Zn1	0.0273 (4)	0.0273 (4)	0.0444 (10)	0.000	0.000	0.000
Se1	0.0366 (4)	0.0310 (3)	0.0429 (4)	0.0011 (3)	−0.0063 (3)	−0.0001 (3)
N1	0.043 (3)	0.029 (3)	0.047 (3)	0.000 (2)	−0.003 (3)	0.001 (3)
C1	0.035 (3)	0.024 (3)	0.039 (3)	0.004 (2)	0.003 (3)	0.005 (3)

Geometric parameters (Å, º)

Cd1—Se1^i	2.6640 (7)	Zn1—N1^iv	1.959 (7)
Cd1—Se1^ii	2.6640 (7)	Zn1—N1^v	1.959 (7)
Cd1—Se1	2.6640 (7)	Zn1—N1^vi	1.959 (7)
Cd1—Se1^iii	2.6640 (7)	Se1—C1	1.824 (7)
Zn1—N1	1.959 (7)	N1—C1	1.143 (9)
Se1^i—Cd1—Se1^ii	107.709 (16)	N1^iv—Zn1—N1^v	108.3 (2)
Se1^i—Cd1—Se1	107.709 (16)	N1—Zn1—N1^vi	108.3 (2)
Se1^ii—Cd1—Se1	113.06 (3)	N1^iv—Zn1—N1^vi	108.3 (2)
Se1^i—Cd1—Se1^iii	113.06 (3)	N1^v—Zn1—N1^vi	111.8 (4)
Se1^ii—Cd1—Se1^iii	107.709 (16)	C1—Se1—Cd1	94.4 (2)
Se1—Cd1—Se1^iii	107.709 (16)	C1—N1—Zn1	176.2 (6)
N1—Zn1—N1^iv	111.8 (4)	N1—C1—Se1	178.4 (6)
N1—Zn1—N1^v	108.3 (2)
Se1^i—Cd1—Se1—C1	−13.8 (2)	Se1^iii—Cd1—Se1—C1	108.4 (2)
Se1^ii—Cd1—Se1—C1	−132.7 (2)

Symmetry codes: (i) y, −x, −z; (ii) −x, −y, z; (iii) −y, x, −z; (iv) −x, −y+1, z; (v) −y+1/2, x+1/2, −z+1/2; (vi) y−1/2, −x+1/2, −z+1/2.