Poly[(nitrato-κO)tris­(μ₃-1H-1,2,4-triazol­ato)dizinc(II)]: a three-dimensional coordination polymer

In the title compound, [Zn₂(C₂H₂N₃)₃(NO₃)], there are two unique Zn atoms, both with site symmetry m. One forms a ZnN₃O tetra­hedron and the other a ZnN₆ octa­hedron. One and a half 1H-1,2,4-triazolate ligands, with the half-ligand located on a mirror plane, and a disordered nitrate anion complete the asymmetric unit of the structure. The polymeric connectivity is three-dimensional.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](N-C) = 0.003 Å
• Disorder in main residue
• R factor = 0.024
• wR factor = 0.062
• Data-to-parameter ratio = 13.5

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.808     1.000
            Tmin and Tmax expected:      0.306     0.449
            RR =      1.184
            Please check that your absorption correction is appropriate.
PLAT060_ALERT_3_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       1.18
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.45
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for        O2A
PLAT301_ALERT_3_C Main Residue  Disorder .........................      14.00 Perc.
PLAT313_ALERT_2_C Oxygen with three covalent bonds (rare) ........        O2B
PLAT313_ALERT_2_C Oxygen with three covalent bonds (rare) ........        O3B

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.449
            Tmax scaled      0.449 Tmin scaled      0.363
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          3

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   5 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The title compound, (I), was solvothermally synthesized from Zn(NO₃)₂ and 1,2,4–1H-triazole (Htrz) in a 1:1 molar ratio in an ethanol/water solvent mixture. Single crystal X-ray analysis determined that the transparent crystals contain a complicated three-dimensional atomic network whose asymmetric unit is shown in Figure 1. There are two crystallographically distinct Zn centers (Figure 2). Zn1 atoms are in a tetrahedral coordination sphere, coordinated to three trz ligands and one disordered NO₃. Zn2 atoms are in an octahedral coordination sphere, coordinated to six trz ligands (Figure 2 b). The nitrate anion coordinated to Zn1 is disordered over two independent positions in the asymmetric unit, and three positions when the mirror symmetry of the crystal is taken into account, in the proportion 40/40/20 (Figure 2a). Each Zn center forms its own one-dimensional chain/column along the a axis through the anionic bridging mode of the trz ligands, whose connectives generate a three-dimensional structure (Figure 3). Zn2 and its ligands form infinite one-dimensional chains down the a axis. These one-dimensional chains propagate by the N1,N2 bridging mode (see Figure 4) of the trz ligands. Each Zn2 one-dimensional chain is bridged via a N4 mode to columns of tetrahedrally coordinated Zn1 atoms. The Zn—O and Zn—N bond distances (Table 1) are comparable to those in an isostructural complex synthesized with Co (Ouellette et al., 2006). Additionally, the bridging characteristics of trz in [Zn₂(trz)₃(NO₃)] are similar to our previous work involving trz and ZnF, in that all trz ring nitrogen atoms coordinate to the Zn centers through an N1,N2,N4 bridging mode (Goforth et al., 2005; Su et al., 2004).

Related literature

For the isostructural Co phase, see: Ouellette et al. (2006). For related literature, see: Goforth et al. (2005); Su et al. (2004).

S2. Experimental

In a typical procedure trz (0.5 mmol) and Zn(NO₃)₂ (0.5 mmol) were weighed and placed in a 23 ml Teflon lined autoclave together with 5 ml water and 5 ml e thanol, which functioned as the reaction solvent. The autoclave was subsequently sealed and heated at a rate of 1 K/min to 433 K. The temperature was held at 433 K for three days before it was decreased, at a rate of 0.1 K/min, to 353 K where it was then held for 6 h. Finally, the temperature was decreased at a rate of 0.1 K/min to room temperature. Colorless blocks of (I) were hand picked from the reaction and used for single-crystal analyses.

S3. Refinement

The atoms of the minor nitrate disorder component were refined with U_iso values. The hydrogen atoms were placed in geometrically idealized positions and included as riding atoms. The final difference map extrema are +0.84 e-/Å3 (0.98 Å from Zn1) and -0.52 e-/Å3 (0.51 Å from O1B).

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: various; software used to prepare material for publication: SHELXTL (Bruker, 2000).

Figures

	Fig. 1. Two views of the asymmetric unit of (I). Displacement ellipsoids are drawn at the 50% probability level. The asymmetric unit is on a mirror plane containing Zn1, Zn2 trz ligand {N1}, and component N7B of the disordered nitrate anion.
	Fig. 2. (a) Tetrahedral coordination around Zn2. Disordered nitrate mirror plane is vertical and nearly perpendicular to figure. Occupancies: N7A = N7A* = 40%, N7B = 20%. (b) Octahedral coordination around Zn2. Mirror plane is vertical and nearly perpendicular to figure.
	Fig. 3. View down a axis of the three-dimensional structure (top). Columns of tetrahedrally coordinated Zn1 atoms (bottom left). one-dimensional chains of Zn1 atoms (bottom right). Zn1 lighter green; Zn2 darker green.
	Fig. 4. Labeling scheme of coordination modes in 1,2,4-triazoles

Poly[(nitrato-κO)tris(µ₃-1H-1,2,4-triazolato)dizinc(II)]

Crystal data

[Zn2(C2H2N3)3(NO3)]	F(000) = 784
Mr = 396.95	Dx = 1.986 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 5133 reflections
a = 7.6001 (4) Å	θ = 2.4–28.3°
b = 9.9758 (5) Å	µ = 3.64 mm^−1
c = 17.5108 (8) Å	T = 150 K
V = 1327.62 (11) Å^3	Block, colorless
Z = 4	0.36 × 0.28 × 0.22 mm

Data collection

Bruker SMART APEX CCD diffractometer	1752 independent reflections
Radiation source: fine-focus sealed tube	1627 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
ω scans	θmax = 28.3°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −10→10
Tmin = 0.808, Tmax = 1.000	k = −13→13
12217 measured reflections	l = −22→23

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.025	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.062	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0321P)^2 + 0.8204P] where P = (Fo^2 + 2Fc^2)/3
1752 reflections	(Δ/σ)max = 0.001
130 parameters	Δρmax = 0.84 e Å^−3
3 restraints	Δρmin = −0.52 e Å^−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	Occ. (<1)
Zn1	0.65025 (4)	0.7500	0.580742 (16)	0.01318 (10)
Zn2	0.51023 (3)	0.7500	0.237037 (17)	0.01112 (9)
C1	0.5883 (3)	0.7500	0.41412 (15)	0.0190 (6)
H1	0.4647	0.7500	0.4223	0.023*
C2	0.8619 (3)	0.7500	0.43286 (16)	0.0187 (5)
H2	0.9738	0.7500	0.4571	0.022*
C3	0.5824 (2)	0.51411 (19)	0.67750 (11)	0.0180 (4)
H3	0.4628	0.5408	0.6816	0.022*
C4	0.8505 (2)	0.5094 (2)	0.64855 (11)	0.0180 (4)
H4	0.9621	0.5317	0.6277	0.022*
N1	0.7073 (3)	0.7500	0.47113 (13)	0.0161 (4)
N2	0.6611 (3)	0.7500	0.34565 (13)	0.0157 (4)
N3	0.8397 (3)	0.7500	0.35800 (13)	0.0156 (4)
N4	0.7043 (2)	0.58402 (15)	0.63830 (9)	0.0158 (3)
N5	0.64612 (18)	0.40513 (15)	0.70959 (9)	0.0149 (3)
N6	0.82168 (19)	0.40187 (15)	0.69069 (9)	0.0147 (3)
N7A	0.2668 (6)	0.7091 (4)	0.5694 (2)	0.0247 (11)	0.40
O1A	0.3900 (4)	0.7852 (3)	0.5936 (2)	0.0270 (10)	0.40
O2A	0.3091 (7)	0.6066 (5)	0.5355 (3)	0.0520 (13)	0.40
O3A	0.1108 (3)	0.7500	0.58235 (14)	0.0383 (6)	0.80
N7B	0.2657 (13)	0.7500	0.6055 (6)	0.029 (3)*	0.20
O1B	0.3885 (15)	0.7500	0.5567 (7)	0.026 (3)*	0.20
O2B	0.3006 (15)	0.7500	0.6737 (6)	0.033 (3)*	0.20
O3B	0.1108 (3)	0.7500	0.58235 (14)	0.0383 (6)	0.20

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.01843 (17)	0.01104 (16)	0.01007 (16)	0.000	0.00027 (10)	0.000
Zn2	0.00955 (15)	0.01216 (16)	0.01165 (17)	0.000	0.00029 (9)	0.000
C1	0.0141 (12)	0.0284 (15)	0.0145 (13)	0.000	0.0019 (9)	0.000
C2	0.0138 (11)	0.0277 (15)	0.0146 (13)	0.000	−0.0020 (9)	0.000
C3	0.0145 (8)	0.0166 (9)	0.0229 (10)	0.0028 (7)	0.0014 (7)	0.0048 (8)
C4	0.0160 (8)	0.0179 (9)	0.0201 (10)	−0.0005 (7)	0.0029 (7)	0.0052 (8)
N1	0.0179 (10)	0.0191 (11)	0.0114 (10)	0.000	−0.0003 (8)	0.000
N2	0.0121 (10)	0.0237 (12)	0.0114 (10)	0.000	0.0001 (8)	0.000
N3	0.0123 (10)	0.0201 (11)	0.0143 (11)	0.000	0.0002 (8)	0.000
N4	0.0181 (7)	0.0137 (8)	0.0155 (8)	0.0009 (6)	−0.0004 (6)	0.0013 (6)
N5	0.0117 (7)	0.0152 (8)	0.0179 (8)	0.0008 (5)	0.0008 (6)	0.0032 (6)
N6	0.0121 (7)	0.0157 (8)	0.0164 (8)	−0.0002 (5)	0.0004 (5)	0.0022 (6)
N7A	0.030 (2)	0.027 (3)	0.018 (2)	−0.0082 (16)	−0.0016 (17)	0.0046 (17)
O1A	0.0148 (16)	0.026 (3)	0.040 (2)	−0.0033 (12)	−0.0037 (15)	−0.0135 (16)
O2A	0.047 (3)	0.039 (3)	0.070 (4)	−0.009 (2)	−0.002 (3)	−0.029 (3)
O3A	0.0173 (10)	0.0551 (17)	0.0425 (15)	0.000	−0.0022 (10)	0.000
O3B	0.0173 (10)	0.0551 (17)	0.0425 (15)	0.000	−0.0022 (10)	0.000

Geometric parameters (Å, º)

Zn1—N1	1.968 (2)	C3—N5	1.316 (2)
Zn1—N4^i	1.9814 (16)	C3—N4	1.348 (2)
Zn1—N4	1.9815 (15)	C3—H3	0.9500
Zn1—O1A^i	2.021 (4)	C4—N6	1.320 (2)
Zn1—O1A	2.021 (4)	C4—N4	1.349 (2)
Zn1—O1B	2.033 (12)	C4—H4	0.9500
Zn2—N3^ii	2.109 (2)	N2—N3	1.375 (3)
Zn2—N6^iii	2.1415 (15)	N3—Zn2^vii	2.109 (2)
Zn2—N6^iv	2.1415 (15)	N5—N6	1.375 (2)
Zn2—N5^v	2.1634 (15)	N5—Zn2^vi	2.1635 (15)
Zn2—N5^vi	2.1635 (15)	N6—Zn2^viii	2.1415 (15)
Zn2—N2	2.221 (2)	N7A—O2A	1.225 (6)
C1—N2	1.321 (3)	N7A—O3A	1.274 (5)
C1—N1	1.347 (3)	N7A—O1A	1.277 (5)
C1—H1	0.9500	O3A—N7A^i	1.274 (5)
C2—N3	1.322 (3)	N7B—O2B	1.222 (11)
C2—N1	1.353 (3)	N7B—O1B	1.266 (11)
C2—H2	0.9500
N1—Zn1—N4^i	116.77 (5)	C1—N1—C2	102.5 (2)
N1—Zn1—N4	116.77 (5)	C1—N1—Zn1	125.11 (18)
N4^i—Zn1—N4	113.36 (9)	C2—N1—Zn1	132.41 (19)
N1—Zn1—O1A^i	108.90 (13)	C1—N2—N3	105.7 (2)
N4^i—Zn1—O1A^i	106.94 (11)	C1—N2—Zn2	124.16 (17)
N4—Zn1—O1A^i	90.08 (11)	N3—N2—Zn2	130.14 (17)
N1—Zn1—O1A	108.90 (13)	C2—N3—N2	106.4 (2)
N4^i—Zn1—O1A	90.08 (11)	C2—N3—Zn2^vii	134.77 (17)
N4—Zn1—O1A	106.94 (12)	N2—N3—Zn2^vii	118.86 (17)
N1—Zn1—O1B	90.8 (3)	C3—N4—C4	102.28 (15)
N4^i—Zn1—O1B	107.94 (17)	C3—N4—Zn1	123.29 (12)
N4—Zn1—O1B	107.94 (17)	C4—N4—Zn1	134.40 (13)
N3^ii—Zn2—N6^iii	93.87 (6)	C3—N5—N6	105.90 (15)
N3^ii—Zn2—N6^iv	93.87 (6)	C3—N5—Zn2^vi	124.97 (12)
N6^iii—Zn2—N6^iv	90.06 (8)	N6—N5—Zn2^vi	128.32 (11)
N3^ii—Zn2—N5^v	90.20 (6)	C4—N6—N5	106.04 (14)
N6^iii—Zn2—N5^v	89.16 (6)	C4—N6—Zn2^viii	133.44 (12)
N6^iv—Zn2—N5^v	175.90 (6)	N5—N6—Zn2^viii	120.29 (11)
N3^ii—Zn2—N5^vi	90.20 (6)	N7A^i—N7A—O1A^i	86.8 (3)
N6^iii—Zn2—N5^vi	175.90 (6)	N7A^i—N7A—O2A	146.6 (3)
N6^iv—Zn2—N5^vi	89.16 (6)	O1A^i—N7A—O2A	90.4 (4)
N5^v—Zn2—N5^vi	91.34 (8)	N7A^i—N7A—O3A	71.34 (19)
N3^ii—Zn2—N2	173.18 (8)	O1A^i—N7A—O3A	139.1 (5)
N6^iii—Zn2—N2	90.95 (6)	O2A—N7A—O3A	126.7 (4)
N6^iv—Zn2—N2	90.95 (6)	N7A^i—N7A—O1A	53.6 (3)
N5^v—Zn2—N2	85.04 (6)	O2A—N7A—O1A	117.6 (4)
N5^vi—Zn2—N2	85.04 (6)	O3A—N7A—O1A	115.7 (4)
N2—C1—N1	113.1 (2)	O1A^i—O1A—N7A^i	93.2 (3)
N2—C1—H1	123.5	O1A^i—O1A—N7A	53.6 (3)
N1—C1—H1	123.5	O1A^i—O1A—O2A^i	132.2 (3)
N3—C2—N1	112.4 (2)	N7A^i—O1A—O2A^i	49.7 (3)
N3—C2—H2	123.8	N7A—O1A—O2A^i	84.7 (3)
N1—C2—H2	123.8	O1A^i—O1A—Zn1	80.01 (10)
N5—C3—N4	113.07 (16)	N7A^i—O1A—Zn1	148.6 (4)
N5—C3—H3	123.5	N7A—O1A—Zn1	125.3 (3)
N4—C3—H3	123.5	O2A^i—O1A—Zn1	114.9 (3)
N6—C4—N4	112.71 (16)	O2B—N7B—O1B	119.9 (12)
N6—C4—H4	123.6	N7B—O1B—Zn1	125.6 (10)
N4—C4—H4	123.6
N2—C1—N1—C2	0.0	Zn2^vi—N5—N6—C4	169.93 (14)
N2—C1—N1—Zn1	180.0	C3—N5—N6—Zn2^viii	175.21 (12)
N3—C2—N1—C1	0.0	Zn2^vi—N5—N6—Zn2^viii	−14.9 (2)
N3—C2—N1—Zn1	180.0	N7A^i—N7A—O1A—O1A^i	−179.988 (2)
N4^i—Zn1—N1—C1	−110.62 (6)	O2A—N7A—O1A—O1A^i	−38.3 (4)
N4—Zn1—N1—C1	110.62 (6)	O3A—N7A—O1A—O1A^i	142.7 (5)
O1A^i—Zn1—N1—C1	10.57 (10)	O1A^i—N7A—O1A—N7A^i	180.0
O1A—Zn1—N1—C1	−10.57 (10)	O2A—N7A—O1A—N7A^i	141.7 (4)
O1B—Zn1—N1—C1	0.0	O3A—N7A—O1A—N7A^i	−37.3 (5)
N4^i—Zn1—N1—C2	69.38 (6)	N7A^i—N7A—O1A—O2A^i	−24.9 (3)
N4—Zn1—N1—C2	−69.38 (6)	O1A^i—N7A—O1A—O2A^i	155.1 (3)
O1A^i—Zn1—N1—C2	−169.43 (10)	O2A—N7A—O1A—O2A^i	116.8 (6)
O1A—Zn1—N1—C2	169.43 (10)	O3A—N7A—O1A—O2A^i	−62.2 (4)
O1B—Zn1—N1—C2	180.0	N7A^i—N7A—O1A—Zn1	−141.8 (5)
N1—C1—N2—N3	0.000 (1)	O1A^i—N7A—O1A—Zn1	38.2 (5)
N1—C1—N2—Zn2	180.0	O2A—N7A—O1A—Zn1	−0.2 (7)
N6^iii—Zn2—N2—C1	134.96 (4)	O3A—N7A—O1A—Zn1	−179.1 (3)
N6^iv—Zn2—N2—C1	−134.96 (4)	N1—Zn1—O1A—O1A^i	93.45 (4)
N5^v—Zn2—N2—C1	45.89 (4)	N4^i—Zn1—O1A—O1A^i	−148.08 (5)
N5^vi—Zn2—N2—C1	−45.89 (4)	N4—Zn1—O1A—O1A^i	−33.57 (5)
N6^iii—Zn2—N2—N3	−45.04 (4)	O1B—Zn1—O1A—O1A^i	62.5 (6)
N6^iv—Zn2—N2—N3	45.04 (4)	N1—Zn1—O1A—N7A^i	13.9 (7)
N5^v—Zn2—N2—N3	−134.11 (4)	N4^i—Zn1—O1A—N7A^i	132.4 (7)
N5^vi—Zn2—N2—N3	134.11 (4)	N4—Zn1—O1A—N7A^i	−113.1 (7)
N1—C2—N3—N2	0.0	O1A^i—Zn1—O1A—N7A^i	−79.6 (7)
N1—C2—N3—Zn2^vii	180.0	O1B—Zn1—O1A—N7A^i	−17.1 (6)
C1—N2—N3—C2	0.000 (1)	N1—Zn1—O1A—N7A	63.1 (4)
Zn2—N2—N3—C2	180.0	N4^i—Zn1—O1A—N7A	−178.4 (4)
C1—N2—N3—Zn2^vii	180.0	N4—Zn1—O1A—N7A	−63.9 (4)
Zn2—N2—N3—Zn2^vii	0.0	O1A^i—Zn1—O1A—N7A	−30.3 (4)
N5—C3—N4—C4	0.0 (2)	O1B—Zn1—O1A—N7A	32.1 (6)
N5—C3—N4—Zn1	178.11 (13)	N1—Zn1—O1A—O2A^i	−38.7 (3)
N6—C4—N4—C3	0.0 (2)	N4^i—Zn1—O1A—O2A^i	79.8 (3)
N6—C4—N4—Zn1	−177.80 (14)	N4—Zn1—O1A—O2A^i	−165.7 (3)
N1—Zn1—N4—C3	−122.50 (16)	O1A^i—Zn1—O1A—O2A^i	−132.1 (3)
N4^i—Zn1—N4—C3	97.36 (16)	O1B—Zn1—O1A—O2A^i	−69.6 (6)
O1A^i—Zn1—N4—C3	−11.19 (19)	N7A^i—N7A—O2A—O1A^i	84.9 (6)
O1A—Zn1—N4—C3	−0.29 (19)	O3A—N7A—O2A—O1A^i	−161.3 (7)
O1B—Zn1—N4—C3	−22.2 (3)	O1A—N7A—O2A—O1A^i	19.9 (3)
N1—Zn1—N4—C4	54.9 (2)	O1A^i—N7A—O3A—N7A^i	61.4 (7)
N4^i—Zn1—N4—C4	−85.2 (2)	O2A—N7A—O3A—N7A^i	−147.9 (5)
O1A^i—Zn1—N4—C4	166.2 (2)	O1A—N7A—O3A—N7A^i	31.0 (4)
O1A—Zn1—N4—C4	177.1 (2)	O2B—N7B—O1B—Zn1	0.000 (4)
O1B—Zn1—N4—C4	155.3 (4)	N1—Zn1—O1B—N7B	180.000 (3)
N4—C3—N5—N6	0.0 (2)	N4^i—Zn1—O1B—N7B	−61.44 (11)
N4—C3—N5—Zn2^vi	−170.37 (13)	N4—Zn1—O1B—N7B	61.44 (11)
N4—C4—N6—N5	0.0 (2)	O1A^i—Zn1—O1B—N7B	29.2 (5)
N4—C4—N6—Zn2^viii	−174.30 (13)	O1A—Zn1—O1B—N7B	−29.2 (5)
C3—N5—N6—C4	0.0 (2)

Symmetry codes: (i) x, −y+3/2, z; (ii) x−1/2, y, −z+1/2; (iii) −x+3/2, y+1/2, z−1/2; (iv) −x+3/2, −y+1, z−1/2; (v) −x+1, y+1/2, −z+1; (vi) −x+1, −y+1, −z+1; (vii) x+1/2, y, −z+1/2; (viii) −x+3/2, −y+1, z+1/2.