Phase transitions in ferroelectric 4-amino­pyridinium tetra­chloro­antimonate(III) – revisited

New X-ray diffraction studies on the crystal structure of ferroelectric [4-NH₂C₅H₄NH][SbCl₄] indicate that in the broad temperature range from 240 to 304 K covering the three intermediate phases, the crystal structure is modulated. Phase II is incommensurately modulated with modulation vector q = βb*, β varying from 0.60 to 0.66 and monoclinic C2/c(0β0)s0 superspace group. Ferroelectric phase III is commensurate with q = b* and Cc(0β0)0 symmetry. Polar phase IV is incommensurately modulated with β varying from 0.66 to 0.70 and Cc(0β0)0 superspace group. In all phases only first-order satellites are observed along the b* direction. Two types of periodic deformation are present in the structure of modulated phases. The 4-amino­pyridinium cations are subjected to occupation modulation whereas [SbCl₄]⁻_n chains are displacively modulated. The paraelectric–ferroelectric phase transition is an example of the incommensurate–commensurate transition of the lock-in type. A new mechanism for this transformation is proposed.

Computing details

For all structures, data collection: CrysAlis PRO 1.171.38.43 (Rigaku OD, 2015); cell refinement: CrysAlis PRO 1.171.38.43 (Rigaku OD, 2015); data reduction: CrysAlis PRO 1.171.38.43 (Rigaku OD, 2015).

(I)

Crystal data

C5H7Cl4N2Sb	F(000) = 680
Mr = 358.7	Dx = 2.117 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 5267 reflections
a = 13.4747 (4) Å	θ = 3.3–29.2°
b = 12.9393 (4) Å	µ = 3.35 mm^−1
c = 7.7611 (2) Å	T = 320 K
β = 123.733 (2)°	Prism
V = 1125.34 (6) Å^3	0.23 × 0.16 × 0.10 mm
Z = 4

Data collection

Xcalibur, Atlas diffractometer	1419 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	1295 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.016
Detector resolution: 10.6249 pixels mm^-1	θmax = 29.4°, θmin = 2.4°
Absorption correction: multi-scan CrysAlisPro 1.171.38.43 (Rigaku Oxford Diffraction, 2015) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −18→17
Tmin = 0.852, Tmax = 1.000	k = −17→17
7260 measured reflections	l = −10→10

Refinement

Refinement on F^2	0 constraints
R[F^2 > 2σ(F^2)] = 0.030	H-atom parameters constrained
wR(F^2) = 0.094	Weighting scheme based on measured s.u.'s w = 1/(σ^2(I) + 0.0016I^2)
S = 1.95	(Δ/σ)max = 0.029
1295 reflections	Δρmax = 0.84 e Å^−3
39 parameters	Δρmin = −0.56 e Å^−3
13 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Sb	0.5	0.57454 (2)	0.75	0.04426 (19)
Cl1	0.37927 (11)	0.70152 (10)	0.4950 (2)	0.0784 (6)
Cl2	0.64928 (10)	0.58102 (8)	0.6295 (2)	0.0647 (5)
Na	0.1597 (8)	0.6524 (10)	0.0512 (15)	0.099 (4)	0.5
N1a	−0.1256 (8)	0.5220 (7)	−0.4734 (14)	0.099 (4)	0.5
C2a	−0.0378 (9)	0.4598 (7)	−0.3230 (17)	0.099 (4)	0.5
C3a	0.0607 (9)	0.5040 (8)	−0.1533 (17)	0.099 (4)	0.5
C4a	0.0638 (7)	0.6117 (8)	−0.1316 (15)	0.099 (4)	0.5
C5a	−0.0249 (9)	0.6775 (7)	−0.2815 (18)	0.099 (4)	0.5
C6a	−0.1179 (9)	0.6290 (7)	−0.4571 (16)	0.099 (4)	0.5
H1n1a	−0.187525	0.493855	−0.581753	0.1183*	0.5
H1c3a	0.126061	0.462108	−0.051507	0.1183*	0.5
H1c5a	−0.02161	0.751086	−0.2639	0.1183*	0.5
H1c2a	−0.0452	0.3859	−0.3362	0.1183*	0.5
H1c6a	−0.1782	0.6703	−0.5697	0.1183*	0.5
H1na	0.2149	0.6116	0.1444	0.1183*	0.5
H2na	0.1647	0.7188	0.0727	0.1183*	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb	0.0434 (2)	0.0487 (2)	0.0417 (2)	0	0.02426 (16)	0
Cl1	0.0731 (6)	0.0751 (7)	0.0876 (7)	0.0245 (5)	0.0450 (6)	0.0343 (6)
Cl2	0.0505 (5)	0.0800 (7)	0.0650 (6)	−0.0007 (4)	0.0330 (5)	−0.0027 (4)
Na	0.104 (4)	0.122 (4)	0.109 (4)	−0.030 (3)	0.084 (4)	−0.037 (3)
N1a	0.104 (4)	0.122 (4)	0.109 (4)	−0.030 (3)	0.084 (4)	−0.037 (3)
C2a	0.104 (4)	0.122 (4)	0.109 (4)	−0.030 (3)	0.084 (4)	−0.037 (3)
C3a	0.104 (4)	0.122 (4)	0.109 (4)	−0.030 (3)	0.084 (4)	−0.037 (3)
C4a	0.104 (4)	0.122 (4)	0.109 (4)	−0.030 (3)	0.084 (4)	−0.037 (3)
C5a	0.104 (4)	0.122 (4)	0.109 (4)	−0.030 (3)	0.084 (4)	−0.037 (3)
C6a	0.104 (4)	0.122 (4)	0.109 (4)	−0.030 (3)	0.084 (4)	−0.037 (3)

Geometric parameters (Å, º)

Sb—Cl1	2.3848 (12)	Sb—Cl2^i	2.6488 (18)
Sb—Cl1^i	2.3848 (12)	Sb—Cl2^ii	3.1927 (11)
Sb—Cl2	2.6488 (18)	Sb—Cl2^iii	3.1927 (11)
Cl1—Sb—Cl1^i	92.90 (4)	Cl1^i—Sb—Cl2^iii	83.04 (4)
Cl1—Sb—Cl2	89.26 (5)	Cl2—Sb—Cl2^i	176.37 (3)
Cl1—Sb—Cl2^i	88.24 (5)	Cl2—Sb—Cl2^ii	84.67 (4)
Cl1—Sb—Cl2^ii	83.04 (4)	Cl2—Sb—Cl2^iii	97.63 (4)
Cl1—Sb—Cl2^iii	171.87 (5)	Cl2^i—Sb—Cl2^ii	97.63 (4)
Cl1^i—Sb—Cl2	88.24 (5)	Cl2^i—Sb—Cl2^iii	84.67 (4)
Cl1^i—Sb—Cl2^i	89.26 (5)	Cl2^ii—Sb—Cl2^iii	101.83 (3)
Cl1^i—Sb—Cl2^ii	171.87 (5)

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

(II)

Crystal data

C5H7Cl4N2Sb	F(000) = 680
Mr = 358.69	Dx = 2.091 Mg m^−3
Monoclinic, C2/c(0β0)s0†	Mo Kα radiation, λ = 0.71073 Å
q = 0.586000b*	Cell parameters from 9808 reflections
a = 13.3923 Å	θ = 3.3–29.1°
b = 12.815 Å	µ = 3.38 mm^−1
c = 7.8256 Å	T = 290 K
β = 123.735°	Prism
V = 1116.90 Å^3	0.23 × 0.16 × 0.10 mm
Z = 4

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂, −x₃+1/2, x₄+1/2; (3) −x₁, −x₂, −x₃, −x₄; (4) x₁, −x₂, x₃+1/2, −x₄+1/2; (5) x₁+1/2, x₂+1/2, x₃, x₄; (6) −x₁+1/2, x₂+1/2, −x₃+1/2, x₄+1/2; (7) −x₁+1/2, −x₂+1/2, −x₃, −x₄; (8) x₁+1/2, −x₂+1/2, x₃+1/2, −x₄+1/2.

Data collection

Xcalibur, Atlas diffractometer	4209 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	2539 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.018
Detector resolution: 10.6249 pixels mm^-1	θmax = 29.4°, θmin = 2.4°
Absorption correction: multi-scan CrysAlisPro 1.171.38.43 (Rigaku Oxford Diffraction, 2015) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −17→18
Tmin = 0.840, Tmax = 1.000	k = −18→18
21939 measured reflections	l = −10→10

Refinement

Refinement on F^2	28 constraints
R[F^2 > 2σ(F^2)] = 0.027	H-atom parameters constrained
wR(F^2) = 0.095	Weighting scheme based on measured s.u.'s w = 1/(σ^2(I) + 0.0016I^2)
S = 1.82	(Δ/σ)max = 0.049
2539 reflections	Δρmax = 0.52 e Å^−3
133 parameters	Δρmin = −0.71 e Å^−3
0 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Sb1	0.5	0.573560 (18)	0.75	0.03484 (16)
Cl2	0.37993 (7)	0.70182 (7)	0.49724 (13)	0.0598 (4)
Cl3	0.65132 (7)	0.58010 (6)	0.63310 (14)	0.0515 (4)
Naa	0.1529 (8)	0.6567 (7)	0.0376 (13)	0.075 (3)	0.5
C3aa	−0.0255 (10)	0.6792 (10)	−0.2875 (17)	0.053 (4)	0.5
C2aa	−0.1162 (12)	0.6301 (14)	−0.455 (2)	0.083 (5)	0.4964
N1aa	−0.1272 (13)	0.5277 (13)	−0.477 (2)	0.101 (4)	0.5
C6aa	−0.0440 (15)	0.4658 (11)	−0.327 (3)	0.083 (5)	0.5
C5aa	0.0521 (13)	0.5063 (9)	−0.151 (2)	0.067 (4)	0.5
C4aa	0.0613 (10)	0.6123 (7)	−0.1310 (17)	0.052 (3)	0.5
H1naa	0.201224	0.618743	0.144936	0.0896*	0.5
H2naa	0.164406	0.723652	0.040527	0.0896*	0.5
H1c3aa	−0.020035	0.753805	−0.275539	0.0641*	0.5
H1c2aa	−0.177153	0.672471	−0.564569	0.0996*	0.5
H1c6aa	−0.052276	0.391434	−0.344508	0.1*	0.5
H1c5aa	0.111394	0.461602	−0.043598	0.0806*	0.5
H1n1aa	−0.187995	0.500705	−0.589147	0.1208*	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb1	0.03412 (19)	0.0376 (2)	0.03173 (19)	0	0.01759 (14)	0
Cl2	0.0560 (5)	0.0570 (5)	0.0613 (5)	0.0162 (3)	0.0294 (4)	0.0223 (4)
Cl3	0.0419 (4)	0.0597 (5)	0.0528 (5)	−0.0001 (3)	0.0262 (4)	−0.0026 (3)
Naa	0.061 (3)	0.092 (4)	0.065 (3)	−0.005 (3)	0.031 (3)	−0.016 (3)
C3aa	0.056 (4)	0.063 (4)	0.049 (4)	0.000 (2)	0.034 (3)	0.002 (2)
C2aa	0.077 (5)	0.120 (6)	0.072 (5)	0.000 (5)	0.053 (5)	−0.014 (5)
N1aa	0.057 (4)	0.194 (8)	0.065 (4)	−0.051 (4)	0.043 (3)	−0.063 (4)
C6aa	0.108 (6)	0.085 (5)	0.102 (5)	−0.029 (5)	0.086 (5)	−0.025 (5)
C5aa	0.089 (4)	0.046 (3)	0.084 (4)	0.000 (3)	0.059 (4)	−0.008 (3)
C4aa	0.054 (3)	0.059 (3)	0.058 (3)	−0.002 (3)	0.041 (3)	−0.006 (3)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Sb1—Cl2	2.3833 (11)	2.3796 (12)	2.3886 (12)
Sb1—Cl2^i	2.3833 (11)	2.3796 (12)	2.3886 (12)
Sb1—Cl3	2.6493 (17)	2.6179 (18)	2.6810 (18)
Sb1—Cl3^i	2.6487 (17)	2.6179 (18)	2.6810 (18)
Cl2—Sb1—Cl2^i	92.64 (4)	92.63 (4)	92.66 (4)
Cl2—Sb1—Cl3	89.12 (5)	88.09 (5)	90.12 (5)
Cl2—Sb1—Cl3^i	88.42 (5)	87.98 (5)	88.92 (5)
Cl2^i—Sb1—Cl3	88.42 (5)	87.98 (5)	88.92 (5)
Cl2^i—Sb1—Cl3^i	89.14 (5)	88.09 (5)	90.12 (5)
Cl3—Sb1—Cl3^i	176.18 (3)	175.98 (3)	176.39 (3)

Symmetry code: (i) −x₁+1, x₂, −x₃+3/2, x₄+1/2.

(III)

Crystal data

C5H7Cl4N2Sb	F(000) = 675
Mr = 358.69	Dx = 2.157 Mg m^−3
Monoclinic, Cc(0β0)0†	Mo Kα radiation, λ = 0.71073 Å
q = 0.666667b*	Cell parameters from 11628 reflections
a = 13.33 (2) Å	θ = 3.2–29.1°
b = 12.690 (9) Å	µ = 3.42 mm^−1
c = 7.87 (2) Å	T = 260 K
β = 123.8 (2)°	Prism
V = 1106 (3) Å^3	0.23 × 0.16 × 0.10 mm
Z = 4

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) x₁, −x₂, x₃+1/2, −x₄; (3) x₁+1/2, x₂+1/2, x₃, x₄; (4) x₁+1/2, −x₂+1/2, x₃+1/2, −x₄.

Data collection

Xcalibur, Atlas diffractometer	7836 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	5379 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.017
Detector resolution: 10.6249 pixels mm^-1	θmax = 29.6°, θmin = 2.4°
Absorption correction: multi-scan CrysAlisPro 1.171.38.43 (Rigaku Oxford Diffraction, 2015) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −17→18
Tmin = 0.858, Tmax = 1.000	k = −17→17
21857 measured reflections	l = −10→10

Refinement

Refinement on F^2	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.036	Weighting scheme based on measured s.u.'s w = 1/(σ^2(I) + 0.0016I^2)
wR(F^2) = 0.121	(Δ/σ)max = 0.029
S = 2.26	Δρmax = 1.06 e Å^−3
5379 reflections	Δρmin = −0.84 e Å^−3
151 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
20 restraints	Extinction coefficient: −320 (140)
3 constraints	Absolute structure: 2585 of Friedel pairs used in the refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Sb	0.52316 (3)	0.572651 (17)	0.71584 (4)	0.02826 (14)
Cl1a	0.40429 (13)	0.70193 (12)	0.4637 (2)	0.0465 (7)
Cl1b	0.64468 (13)	0.70128 (12)	0.96745 (19)	0.0461 (7)
Cl2a	0.67566 (14)	0.58027 (12)	0.5982 (2)	0.0379 (11)
Cl2b	0.37023 (16)	0.57969 (13)	0.8267 (2)	0.0459 (13)
Naa	0.1844 (3)	0.6582 (4)	0.0154 (4)	0.0640 (16)	0.6
C5aa	0.0097 (8)	0.6799 (7)	−0.3078 (11)	0.0640 (16)	0.6
C6aa	−0.0853 (8)	0.6322 (7)	−0.4842 (11)	0.0640 (16)	0.6
N1aa	−0.0941 (7)	0.5242 (7)	−0.5028 (10)	0.0640 (16)	0.6
C2aa	−0.0109 (7)	0.4600 (8)	−0.3501 (10)	0.0640 (16)	0.6
C3aa	0.0875 (7)	0.4988 (6)	−0.1713 (11)	0.0640 (16)	0.6
C4aa	0.0919 (4)	0.6073 (4)	−0.1607 (5)	0.0640 (16)	0.6
H1a	0.188291	0.726659	0.01968	0.0768*	0.6
H2a	0.238129	0.621355	0.120581	0.0768*	0.6
H1c5aa	0.018135	0.754821	−0.288552	0.0768*	0.6
H1c6aa	−0.14542	0.675304	−0.594509	0.0768*	0.6
H1c2aa	−0.021417	0.385092	−0.367974	0.0768*	0.6
H1c3aa	0.147671	0.454415	−0.063794	0.0768*	0.6
H1n1aa	−0.154208	0.496296	−0.614633	0.0768*	0.6
Nba	−0.1268 (4)	0.6204 (4)	−0.5880 (4)	0.062 (2)	0.4
C5ba	0.0321 (10)	0.6931 (6)	−0.2608 (11)	0.062 (2)	0.4
C6ba	0.1268 (9)	0.6775 (7)	−0.0632 (11)	0.062 (2)	0.4
N1ba	0.1653 (7)	0.5763 (7)	0.0011 (10)	0.062 (2)	0.4
C2ba	0.1023 (8)	0.4898 (7)	−0.1188 (11)	0.062 (2)	0.4
C3ba	0.0027 (8)	0.5065 (6)	−0.3155 (11)	0.062 (2)	0.4
C4ba	−0.0251 (4)	0.6083 (5)	−0.3877 (6)	0.062 (2)	0.4
H1ba	−0.140533	0.680443	−0.650729	0.0745*	0.4
H2ba	−0.176189	0.567897	−0.649548	0.0745*	0.4
H1n1ba	0.231314	0.566144	0.120866	0.0745*	0.4
H1c5ba	0.005402	0.763388	−0.311052	0.0745*	0.4
H1c4ba	0.16552	0.735979	0.028287	0.0745*	0.4
H1c2ba	0.127171	0.41963	−0.066396	0.0745*	0.4
H1c3ba	−0.045686	0.448493	−0.399565	0.0745*	0.4

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb	0.02837 (16)	0.02888 (18)	0.02555 (16)	−0.0003 (2)	0.01376 (12)	0.0001 (2)
Cl1a	0.0442 (7)	0.0430 (9)	0.0463 (8)	0.0121 (7)	0.0214 (6)	0.0183 (7)
Cl1b	0.0446 (7)	0.0436 (9)	0.0434 (8)	−0.0125 (7)	0.0203 (6)	−0.0108 (7)
Cl2a	0.0287 (10)	0.0424 (12)	0.0391 (14)	0.0020 (6)	0.0166 (10)	−0.0004 (7)
Cl2b	0.0414 (13)	0.0505 (14)	0.0484 (16)	0.0013 (7)	0.0265 (12)	0.0028 (8)
Naa	0.0558 (18)	0.090 (2)	0.0585 (17)	−0.0149 (16)	0.0395 (14)	−0.0240 (15)
C5aa	0.0558 (18)	0.090 (2)	0.0585 (17)	−0.0149 (16)	0.0395 (14)	−0.0240 (15)
C6aa	0.0558 (18)	0.090 (2)	0.0585 (17)	−0.0149 (16)	0.0395 (14)	−0.0240 (15)
N1aa	0.0558 (18)	0.090 (2)	0.0585 (17)	−0.0149 (16)	0.0395 (14)	−0.0240 (15)
C2aa	0.0558 (18)	0.090 (2)	0.0585 (17)	−0.0149 (16)	0.0395 (14)	−0.0240 (15)
C3aa	0.0558 (18)	0.090 (2)	0.0585 (17)	−0.0149 (16)	0.0395 (14)	−0.0240 (15)
C4aa	0.0558 (18)	0.090 (2)	0.0585 (17)	−0.0149 (16)	0.0395 (14)	−0.0240 (15)
Nba	0.070 (2)	0.0538 (19)	0.072 (2)	−0.0040 (18)	0.045 (2)	−0.0024 (19)
C5ba	0.070 (2)	0.0538 (19)	0.072 (2)	−0.0040 (18)	0.045 (2)	−0.0024 (19)
C6ba	0.070 (2)	0.0538 (19)	0.072 (2)	−0.0040 (18)	0.045 (2)	−0.0024 (19)
N1ba	0.070 (2)	0.0538 (19)	0.072 (2)	−0.0040 (18)	0.045 (2)	−0.0024 (19)
C2ba	0.070 (2)	0.0538 (19)	0.072 (2)	−0.0040 (18)	0.045 (2)	−0.0024 (19)
C3ba	0.070 (2)	0.0538 (19)	0.072 (2)	−0.0040 (18)	0.045 (2)	−0.0024 (19)
C4ba	0.070 (2)	0.0538 (19)	0.072 (2)	−0.0040 (18)	0.045 (2)	−0.0024 (19)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Sb—Cl1a	2.382 (5)	2.380 (6)	2.382 (6)
Sb—Cl1b	2.380 (6)	2.374 (6)	2.384 (6)
Sb—Cl2a	2.665 (8)	2.643 (8)	2.697 (8)
Sb—Cl2a^i	3.191 (6)	3.163 (8)	3.206 (8)
Sb—Cl2b	2.630 (8)	2.595 (9)	2.662 (9)
Sb—Cl2b^ii	3.219 (6)	3.180 (8)	3.266 (8)
Naa—C4aa	1.401 (7)	1.401 (7)	1.402 (7)
C5aa—C6aa	1.395 (11)	1.394 (11)	1.396 (11)
C5aa—C4aa	1.409 (9)	1.408 (10)	1.410 (10)
C6aa—N1aa	1.379 (13)	1.378 (13)	1.380 (13)
N1aa—C2aa	1.364 (11)	1.363 (11)	1.365 (11)
C2aa—C3aa	1.377 (11)	1.376 (11)	1.378 (11)
C3aa—C4aa	1.381 (9)	1.380 (9)	1.382 (9)
Nba—C4ba	1.429 (8)	1.429 (8)	1.429 (8)
C5ba—C6ba	1.391 (12)	1.391 (12)	1.391 (12)
C5ba—C4ba	1.399 (10)	1.399 (10)	1.399 (10)
C6ba—N1ba	1.393 (13)	1.393 (13)	1.393 (13)
N1ba—C2ba	1.408 (12)	1.408 (12)	1.408 (12)
C2ba—C3ba	1.410 (11)	1.410 (11)	1.410 (11)
C3ba—C4ba	1.395 (10)	1.395 (10)	1.395 (10)
Cl1a—Sb—Cl1b	92.8 (3)	91.9 (3)	93.3 (3)
Cl1a—Sb—Cl2a	88.2 (2)	87.34 (19)	89.2 (2)
Cl1a—Sb—Cl2a^i	171.30 (13)	169.17 (12)	173.61 (13)
Cl1a—Sb—Cl2b	88.5 (2)	88.24 (19)	89.0 (2)
Cl1a—Sb—Cl2b^ii	81.1 (3)	79.7 (3)	83.4 (3)
Cl1b—Sb—Cl2a	88.1 (2)	87.44 (19)	88.8 (2)
Cl1b—Sb—Cl2a^i	81.5 (3)	80.4 (3)	82.2 (3)
Cl1b—Sb—Cl2b	89.7 (2)	88.45 (19)	91.3 (2)
Cl1b—Sb—Cl2b^ii	170.02 (13)	168.27 (13)	170.97 (14)
Cl2a—Sb—Cl2a^i	98.1 (2)	95.2 (2)	100.0 (2)
Cl2a—Sb—Cl2b	175.56 (10)	175.38 (9)	175.74 (8)
Cl2a—Sb—Cl2b^ii	83.8 (2)	83.1 (2)	85.2 (2)
Cl2a^i—Sb—Cl2b	84.9 (2)	84.2 (2)	86.3 (2)
Cl2a^i—Sb—Cl2b^ii	105.3 (3)	105.2 (3)	105.4 (2)
Cl2b—Sb—Cl2b^ii	98.0 (2)	96.3 (2)	100.8 (2)

Symmetry codes: (i) x₁, −x₂+1, x₃+1/2, −x₄; (ii) x₁, −x₂+1, x₃−1/2, −x₄.

(IV)

Crystal data

C5H7Cl4N2Sb	F(000) = 680
Mr = 358.69	Dx = 2.192 Mg m^−3
Monoclinic, Cc(0β0)0†	Mo Kα radiation, λ = 0.71073 Å
q = 0.668000b*	Cell parameters from 6364 reflections
a = 13.30 (2) Å	θ = 3.3–29.1°
b = 12.660 (18) Å	µ = 3.42 mm^−1
c = 7.89 (2) Å	T = 245 K
β = 123.8 (2)°	Prism
V = 1103 (4) Å^3	0.23 × 0.16 × 0.10 mm
Z = 4

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) x₁, −x₂, x₃+1/2, −x₄; (3) x₁+1/2, x₂+1/2, x₃, x₄; (4) x₁+1/2, −x₂+1/2, x₃+1/2, −x₄.

Data collection

Xcalibur, Atlas diffractometer	7751 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	4489 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.046
Detector resolution: 10.6249 pixels mm^-1	θmax = 29.4°, θmin = 2.4°
Absorption correction: multi-scan CrysAlisPro 1.171.38.43 (Rigaku Oxford Diffraction, 2015) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −17→18
Tmin = 0.843, Tmax = 1.000	k = −17→17
20894 measured reflections	l = −10→10

Refinement

Refinement on Fsqr	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.052	Weighting scheme based on measured s.u.'s w = 1/(σ^2(I) + 0.0016I^2)
wR(F^2) = 0.067	(Δ/σ)max = 0.073
S = 1.90	Δρmax = 1.32 e Å^−3
4489 reflections	Δρmin = −1.24 e Å^−3
135 parameters	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
26 restraints	Extinction coefficient: −420 (120)
3 constraints	Absolute structure: 2000 of Friedel pairs used in the refinement

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Sb1	0.50070 (4)	0.57246 (2)	0.74945 (8)	0.0283 (2)
Cl1a	0.3818 (3)	0.70087 (16)	0.5013 (5)	0.0471 (16)
Cl1b	0.6215 (2)	0.70322 (14)	1.0037 (4)	0.0358 (13)
Cl2a	0.6515 (2)	0.57925 (15)	0.6339 (4)	0.0346 (14)
Cl2b	0.3442 (3)	0.58118 (17)	0.8601 (6)	0.0452 (19)
Naa	0.1702 (7)	0.6597 (5)	0.0634 (10)	0.034*	0.6
C5aa	−0.0132 (9)	0.6767 (4)	−0.2755 (13)	0.0478*	0.6
C6aa	−0.1072 (8)	0.6315 (6)	−0.4532 (11)	0.0421*	0.6
N1aa	−0.1166 (7)	0.5225 (5)	−0.4665 (11)	0.043*	0.6
C2aa	−0.0291 (9)	0.4586 (5)	−0.3095 (14)	0.0417*	0.6
C3aa	0.0695 (8)	0.5033 (5)	−0.1344 (13)	0.0411*	0.6
C4aa	0.0743 (8)	0.6128 (4)	−0.1196 (11)	0.0382*	0.6
H1naa	0.23143	0.621482	0.153043	0.0408*	0.6
H2naa	0.167648	0.726583	0.085938	0.0408*	0.6
H1c5aa	−0.00842	0.752055	−0.259655	0.0574*	0.6
H1c6aa	−0.165065	0.674902	−0.565634	0.0505*	0.6
H1c2aa	−0.03691	0.383151	−0.322237	0.0501*	0.6
H1c3aa	0.132006	0.460113	−0.027539	0.0494*	0.6
H1n1aa	−0.178167	0.493454	−0.574669	0.0516*	0.6
Nba	−0.1635 (12)	0.6286 (7)	−0.5629 (16)	0.0585*	0.4
C5ba	0.0022 (11)	0.6929 (5)	−0.2460 (16)	0.0448*	0.4
C6ba	0.1048 (10)	0.6803 (7)	−0.0504 (15)	0.044*	0.4
N1ba	0.1446 (9)	0.5788 (9)	0.0240 (14)	0.0386*	0.4
C2ba	0.0848 (13)	0.4896 (7)	−0.096 (2)	0.0694*	0.4
C3ba	−0.0215 (11)	0.5029 (6)	−0.2873 (19)	0.0321*	0.4
C4ba	−0.0601 (10)	0.6046 (7)	−0.3635 (14)	0.0418*	0.4
H1nba	−0.186117	0.693899	−0.597613	0.0702*	0.4
H2nba	−0.203645	0.577924	−0.649319	0.0702*	0.4
H1c5ba	−0.025952	0.762489	−0.30024	0.0537*	0.4
H1c6ba	0.147703	0.740763	0.0321	0.0528*	0.4
H1c2ba	0.116893	0.420202	−0.0464	0.0833*	0.4
H1c3ba	−0.067797	0.442653	−0.366019	0.0385*	0.4
H1n1ba	0.207823	0.570439	0.147542	0.0463*	0.4

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb1	0.0287 (2)	0.0246 (2)	0.0340 (3)	0.0056 (3)	0.0190 (2)	0.0043 (3)
Cl1a	0.0452 (17)	0.0444 (12)	0.061 (2)	0.0134 (12)	0.0351 (17)	0.0179 (12)
Cl1b	0.0268 (13)	0.0292 (9)	0.0302 (15)	−0.0047 (9)	0.0027 (13)	−0.0056 (9)
Cl2a	0.0229 (14)	0.0408 (12)	0.0363 (19)	−0.0005 (9)	0.0141 (14)	−0.0104 (10)
Cl2b	0.0382 (18)	0.0376 (13)	0.065 (3)	−0.0024 (10)	0.0317 (19)	−0.0077 (11)

Geometric parameters (Å, º)

	Average	Minimum	Maximum
Sb1—Cl1a	2.359 (6)	2.352 (7)	2.372 (7)
Sb1—Cl1b	2.406 (6)	2.381 (7)	2.426 (7)
Sb1—Cl2a	2.628 (9)	2.564 (9)	2.697 (9)
Sb1—Cl2a^i	3.191 (7)	3.128 (8)	3.246 (8)
Sb1—Cl2b	2.673 (10)	2.639 (11)	2.708 (11)
Sb1—Cl2b^ii	3.239 (7)	3.189 (9)	3.304 (9)
Naa—C4aa	1.428 (16)	1.419 (18)	1.469 (18)
C5aa—C6aa	1.389 (16)	1.381 (18)	1.429 (18)
C5aa—C4aa	1.396 (14)	1.388 (16)	1.436 (16)
C6aa—N1aa	1.392 (19)	1.38 (2)	1.43 (2)
N1aa—C2aa	1.401 (17)	1.393 (19)	1.441 (19)
C2aa—C3aa	1.398 (17)	1.39 (2)	1.44 (2)
Nba—C4ba	1.48 (2)	1.43 (3)	1.71 (3)
C5ba—C6ba	1.43 (3)	1.39 (3)	1.66 (3)
C5ba—C4ba	1.44 (2)	1.39 (2)	1.66 (2)
C6ba—N1ba	1.43 (3)	1.39 (3)	1.65 (3)
N1ba—C2ba	1.44 (3)	1.40 (3)	1.67 (3)
C2ba—C3ba	1.43 (3)	1.39 (3)	1.66 (3)
C3ba—C4ba	1.43 (2)	1.39 (2)	1.66 (2)
Cl1a—Sb1—Cl1b	92.6 (3)	91.6 (3)	93.7 (3)
Cl1a—Sb1—Cl2a	88.9 (2)	87.0 (2)	90.9 (2)
Cl1a—Sb1—Cl2a^i	170.06 (19)	169.20 (18)	170.8 (2)
Cl1a—Sb1—Cl2b	87.6 (2)	85.9 (2)	89.2 (2)
Cl1a—Sb1—Cl2b^ii	81.3 (3)	79.9 (3)	82.5 (3)
Cl1b—Sb1—Cl2a	89.0 (2)	86.5 (2)	91.3 (2)
Cl1b—Sb1—Cl2a^i	81.2 (3)	78.9 (3)	83.4 (2)
Cl1b—Sb1—Cl2b	88.9 (2)	87.1 (2)	90.5 (2)
Cl1b—Sb1—Cl2b^ii	170.83 (17)	167.47 (18)	174.42 (15)
Cl2a—Sb1—Cl2a^i	98.67 (19)	96.7 (2)	100.45 (18)
Cl2a—Sb1—Cl2b	175.48 (11)	174.03 (11)	176.95 (10)
Cl2a—Sb1—Cl2b^ii	84.3 (2)	82.41 (19)	86.3 (2)
Cl2a^i—Sb1—Cl2b	84.6 (2)	82.8 (2)	86.4 (2)
Cl2a^i—Sb1—Cl2b^ii	105.7 (2)	105.4 (2)	106.0 (2)
Cl2b—Sb1—Cl2b^ii	97.4 (2)	93.9 (2)	100.69 (19)

Symmetry codes: (i) x₁, −x₂+1, x₃+1/2, −x₄; (ii) x₁, −x₂+1, x₃−1/2, −x₄.

(V)

Crystal data

C5H7Cl4N2Sb	F(000) = 680
Mr = 358.69	Dx = 2.190 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yabc	Cell parameters from 8893 reflections
a = 13.2080 (4) Å	θ = 3.3–29.1°
b = 12.526 (4) Å	µ = 3.47 mm^−1
c = 7.9251 (3) Å	T = 200 K
β = 123.914 (2)°	Prism
V = 1088.1 (4) Å^3	0.23 × 0.16 × 0.10 mm
Z = 4

Data collection

Xcalibur, Atlas diffractometer	2744 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	2519 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.017
Detector resolution: 10.6249 pixels mm^-1	θmax = 29.5°, θmin = 2.5°
Absorption correction: multi-scan CrysAlisPro 1.171.38.43 (Rigaku Oxford Diffraction, 2015) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −18→17
Tmin = 0.841, Tmax = 1.000	k = −17→17
14021 measured reflections	l = −10→10

Refinement

Refinement on Fsqr	0 constraints
R[F^2 > 2σ(F^2)] = 0.014	H-atom parameters constrained
wR(F^2) = 0.030	Weighting scheme based on measured s.u.'s w = 1/(σ^2(I) + 0.0016I^2)
S = 1.20	(Δ/σ)max = 0.020
2744 reflections	Δρmax = 0.70 e Å^−3
109 parameters	Δρmin = −0.73 e Å^−3
0 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Sb	0.511351 (12)	0.571387 (9)	0.759189 (15)	0.01917 (8)
Cl1a	0.40620 (4)	0.71383 (4)	0.52663 (6)	0.0283 (2)
Cl1b	0.64651 (4)	0.69029 (4)	1.02697 (6)	0.0290 (2)
Cl2a	0.66408 (5)	0.57125 (3)	0.63829 (9)	0.0294 (2)
Cl2b	0.35467 (5)	0.58915 (4)	0.86125 (7)	0.0264 (2)
N	0.16653 (15)	0.65019 (12)	0.0625 (2)	0.0348 (8)
C5	−0.00912 (17)	0.68284 (18)	−0.2746 (2)	0.0283 (9)
C6	−0.1047 (2)	0.64168 (19)	−0.4507 (3)	0.0364 (9)
N1	−0.12220 (17)	0.53468 (16)	−0.4766 (3)	0.0386 (8)
C2	−0.0455 (2)	0.46623 (18)	−0.3300 (4)	0.0385 (12)
C3	0.0533 (2)	0.50224 (16)	−0.1492 (3)	0.0319 (10)
C4	0.07266 (16)	0.61308 (13)	−0.1166 (2)	0.0247 (8)
H1n	0.176746	0.718631	0.084184	0.0417*
H2n	0.217141	0.605788	0.156704	0.0417*
H5	0.002704	0.758687	−0.257763	0.0339*
H6	−0.16061	0.688935	−0.558501	0.0437*
H2	−0.060125	0.390862	−0.352103	0.0462*
H3	0.108761	0.452678	−0.046122	0.0382*
H1	−0.184369	0.509994	−0.590372	0.0463*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sb	0.01957 (9)	0.01811 (10)	0.01690 (9)	−0.00087 (4)	0.00838 (7)	0.00009 (3)
Cl1a	0.0276 (2)	0.0253 (2)	0.0255 (2)	0.00385 (18)	0.0108 (2)	0.00684 (16)
Cl1b	0.0267 (2)	0.0262 (2)	0.0238 (2)	−0.00599 (18)	0.00778 (19)	−0.00451 (16)
Cl2a	0.0254 (3)	0.0293 (3)	0.0326 (3)	0.00092 (16)	0.0157 (2)	−0.00077 (16)
Cl2b	0.0239 (2)	0.0260 (2)	0.0268 (2)	−0.00205 (17)	0.0126 (2)	−0.00051 (17)
N	0.0298 (9)	0.0358 (9)	0.0259 (8)	−0.0016 (8)	0.0076 (7)	−0.0069 (7)
C5	0.0332 (10)	0.0259 (11)	0.0252 (9)	0.0024 (7)	0.0159 (8)	0.0033 (7)
C6	0.0295 (11)	0.0507 (13)	0.0246 (10)	0.0048 (10)	0.0125 (9)	0.0031 (9)
N1	0.0274 (9)	0.0595 (12)	0.0287 (9)	−0.0159 (9)	0.0156 (8)	−0.0190 (8)
C2	0.0502 (14)	0.0338 (12)	0.0453 (13)	−0.0157 (11)	0.0351 (12)	−0.0171 (10)
C3	0.0393 (12)	0.0267 (10)	0.0329 (11)	0.0003 (8)	0.0222 (10)	−0.0018 (8)
C4	0.0255 (9)	0.0268 (9)	0.0244 (9)	0.0012 (8)	0.0155 (8)	−0.0009 (7)

Geometric parameters (Å, º)

Sb—Cl1a	2.3775 (10)	C5—C6	1.357 (2)
Sb—Cl1b	2.3835 (7)	C5—C4	1.410 (2)
Sb—Cl2a	2.6728 (9)	C6—N1	1.356 (3)
Sb—Cl2a^i	3.2155 (8)	N1—C2	1.341 (3)
Sb—Cl2b	2.6181 (7)	C2—C3	1.368 (3)
Sb—Cl2b^ii	3.2068 (10)	C3—C4	1.409 (3)
Cl1a—Sb—Cl1b	92.56 (3)	Cl2a—Sb—Cl2b	174.602 (16)
Cl1a—Sb—Cl2a	87.35 (2)	Cl2a—Sb—Cl2b^ii	101.77 (2)
Cl1a—Sb—Cl2a^i	82.39 (2)	Cl2a^i—Sb—Cl2b	95.06 (2)
Cl1a—Sb—Cl2b	87.43 (2)	Cl2a^i—Sb—Cl2b^ii	106.82 (2)
Cl1a—Sb—Cl2b^ii	167.34 (2)	Cl2b—Sb—Cl2b^ii	83.17 (2)
Cl1b—Sb—Cl2a	88.82 (2)	C6—N1—C2	121.22 (16)
Cl1b—Sb—Cl2a^i	172.66 (2)	N1—C2—C3	121.0 (2)
Cl1b—Sb—Cl2b	90.02 (2)	N—C4—C5	121.47 (16)
Cl1b—Sb—Cl2b^ii	79.02 (3)	N—C4—C3	120.06 (14)
Cl2a—Sb—Cl2a^i	85.64 (2)	C5—C4—C3	118.47 (14)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+1, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N—H1n···Cl2a^iii	0.87	2.69	3.544 (3)	168.60
N—H2n···Cl2a^i	0.87	2.68	3.522 (2)	163.63
N1—H1···Cl2b^iv	0.87	2.41	3.2684 (17)	167.80

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