Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S010827011300930X/sk3472sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827011300930X/sk3472Isup2.hkl |
CCDC reference: 950353
Benzyltrimethylammonium chloride (97%, Alfa Aesar) and CdCl2.2.5H2O (Sinopharm) were used as commercial products without further purification. 1H NMR and 13C NMR spectra were measured on a Bruker Biospin AG Magnet System 300 MHz NMR instrument in D2O solution with trimethylsulfoxane as internal standard. IR spectra (4000–400 cm-1) were recorded on a Shimadzu IR Prestige-21 spectrophotometer with KBr pellets. The melting point was determined using an uncorrected X-4 melting-point apparatus (Beijing Kaifu Company).
Compound (I) was prepared by dissolving equimolar amounts of benzyltrimethylammonium chloride and CdCl2.2.5H2O in a mixture of water and methanol (1/1 v/v) to afford a colourless solution. This solution was left to evaporate at room temperature in air for two weeks to afford colourless plate-like crystals of (I) suitable for single-crystal X-ray diffraction (yield 90%; m.p. 471–472 K with decomposition). 1H NMR (D2O, δ, p.p.m.): 2.91 (s, 9H, CH3), 4.30 (s, 2H, CH2), 7.20–7.37 (5H in phenyl ring); 13C NMR (D2O, δ, p.p.m.): 52.43 (CH3), 69.57 (CH2), 127.38, 129.21, 130.85, 132.85 (C in phenyl ring); IR (KBr pellet, ν, cm-1): 3022, 2986, 2955. 1498, 1471, 1450, 973.
H atoms were placed in calculated positions, with Csp2—H = 0.93 Å, and Csp3—H = 0.96 and 0.97 Å, and treated as riding, with Uiso(H) = 1.2Ueq(Csp2) or 1.5Ueq(Csp3). The refinement of the Flack (1983) parameter [x = -0.07 (4)] clearly indicates the polar space group.
Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
(C10H16N)[CdCl3] | Dx = 1.773 Mg m−3 |
Mr = 368.99 | Melting point = 471–472 K |
Orthorhombic, Pna21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2c -2n | Cell parameters from 12682 reflections |
a = 6.7538 (14) Å | θ = 3.0–27.5° |
b = 22.852 (5) Å | µ = 2.13 mm−1 |
c = 8.9590 (18) Å | T = 291 K |
V = 1382.7 (5) Å3 | Plate, colourless |
Z = 4 | 0.24 × 0.22 × 0.20 mm |
F(000) = 728 |
Rigaku Mercury2 diffractometer | 3167 independent reflections |
Radiation source: fine-focus sealed tube | 2743 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.044 |
Detector resolution: 13.6612 pixels mm-1 | θmax = 27.5°, θmin = 3.2° |
CCD profile fitting scans | h = −8→8 |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005) | k = −29→29 |
Tmin = 0.590, Tmax = 0.650 | l = −11→11 |
13516 measured reflections |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.027 | w = 1/[σ2(Fo2) + (0.0132P)2 + 0.2094P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.056 | (Δ/σ)max < 0.001 |
S = 1.06 | Δρmax = 0.26 e Å−3 |
3167 reflections | Δρmin = −0.41 e Å−3 |
140 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1 restraint | Extinction coefficient: 0.0246 (5) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), with 1482 Bijvoet Pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.07 (4) |
(C10H16N)[CdCl3] | V = 1382.7 (5) Å3 |
Mr = 368.99 | Z = 4 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 6.7538 (14) Å | µ = 2.13 mm−1 |
b = 22.852 (5) Å | T = 291 K |
c = 8.9590 (18) Å | 0.24 × 0.22 × 0.20 mm |
Rigaku Mercury2 diffractometer | 3167 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005) | 2743 reflections with I > 2σ(I) |
Tmin = 0.590, Tmax = 0.650 | Rint = 0.044 |
13516 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | H-atom parameters constrained |
wR(F2) = 0.056 | Δρmax = 0.26 e Å−3 |
S = 1.06 | Δρmin = −0.41 e Å−3 |
3167 reflections | Absolute structure: Flack (1983), with 1482 Bijvoet Pairs |
140 parameters | Absolute structure parameter: −0.07 (4) |
1 restraint |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.4914 (11) | 0.1034 (3) | 0.8740 (5) | 0.092 (2) | |
H1A | 0.4935 | 0.1313 | 0.9540 | 0.137* | |
H1B | 0.6216 | 0.0874 | 0.8606 | 0.137* | |
H1C | 0.4005 | 0.0725 | 0.8979 | 0.137* | |
C2 | 0.5601 (6) | 0.18467 (17) | 0.7107 (7) | 0.0743 (13) | |
H2A | 0.5121 | 0.2076 | 0.6285 | 0.111* | |
H2B | 0.6919 | 0.1713 | 0.6893 | 0.111* | |
H2C | 0.5615 | 0.2081 | 0.7995 | 0.111* | |
C3 | 0.2256 (5) | 0.1557 (2) | 0.7500 (12) | 0.116 (3) | |
H3A | 0.2067 | 0.1879 | 0.6828 | 0.174* | |
H3B | 0.2062 | 0.1688 | 0.8508 | 0.174* | |
H3C | 0.1320 | 0.1254 | 0.7274 | 0.174* | |
C4 | 0.4414 (8) | 0.0915 (2) | 0.6028 (5) | 0.0588 (13) | |
H4A | 0.4182 | 0.1135 | 0.5119 | 0.071* | |
H4B | 0.5756 | 0.0764 | 0.5983 | 0.071* | |
C5 | 0.3023 (7) | 0.04091 (17) | 0.6056 (4) | 0.0487 (10) | |
C6 | 0.3486 (5) | −0.01128 (18) | 0.6770 (4) | 0.0517 (11) | |
H6 | 0.4710 | −0.0155 | 0.7233 | 0.062* | |
C7 | 0.2155 (6) | −0.05671 (16) | 0.6798 (5) | 0.0625 (13) | |
H7 | 0.2488 | −0.0916 | 0.7272 | 0.075* | |
C8 | 0.0355 (7) | −0.0510 (2) | 0.6138 (6) | 0.0732 (14) | |
H8 | −0.0556 | −0.0815 | 0.6183 | 0.088* | |
C9 | −0.0116 (10) | −0.0001 (3) | 0.5405 (7) | 0.100 (2) | |
H9 | −0.1341 | 0.0036 | 0.4941 | 0.120* | |
C10 | 0.1216 (7) | 0.0453 (2) | 0.5354 (5) | 0.0750 (16) | |
H10 | 0.0893 | 0.0794 | 0.4841 | 0.090* | |
Cd1 | 0.63883 (2) | 0.249637 (8) | 0.22732 (13) | 0.03124 (8) | |
Cl1 | 0.38657 (14) | 0.28920 (5) | 0.02411 (8) | 0.0366 (3) | |
Cl2 | 0.39437 (15) | 0.29886 (5) | 0.41788 (9) | 0.0390 (3) | |
Cl3 | 0.38566 (8) | 0.16118 (3) | 0.23929 (13) | 0.0364 (2) | |
N1 | 0.4268 (3) | 0.13288 (10) | 0.7335 (5) | 0.0368 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.146 (6) | 0.087 (4) | 0.042 (3) | −0.036 (4) | −0.024 (3) | 0.016 (3) |
C2 | 0.096 (3) | 0.067 (3) | 0.060 (3) | −0.043 (2) | 0.012 (3) | −0.008 (3) |
C3 | 0.051 (2) | 0.077 (3) | 0.220 (8) | 0.013 (2) | 0.018 (5) | −0.058 (6) |
C4 | 0.097 (4) | 0.048 (3) | 0.031 (2) | −0.007 (3) | 0.015 (2) | −0.001 (2) |
C5 | 0.073 (3) | 0.035 (2) | 0.037 (2) | −0.003 (2) | −0.002 (2) | −0.0065 (17) |
C6 | 0.061 (2) | 0.040 (2) | 0.054 (3) | 0.0121 (19) | 0.0014 (17) | −0.0043 (18) |
C7 | 0.080 (3) | 0.027 (2) | 0.080 (4) | 0.008 (2) | 0.011 (2) | 0.0008 (19) |
C8 | 0.077 (3) | 0.043 (3) | 0.099 (4) | −0.013 (2) | 0.002 (3) | −0.015 (3) |
C9 | 0.094 (4) | 0.059 (3) | 0.148 (6) | −0.012 (3) | −0.059 (5) | −0.009 (5) |
C10 | 0.107 (4) | 0.045 (3) | 0.074 (3) | −0.010 (3) | −0.050 (3) | 0.007 (2) |
Cd1 | 0.01888 (11) | 0.04055 (14) | 0.03429 (13) | −0.00048 (8) | 0.0028 (3) | −0.00021 (14) |
Cl1 | 0.0284 (5) | 0.0486 (7) | 0.0328 (5) | 0.0003 (4) | 0.0029 (5) | 0.0073 (5) |
Cl2 | 0.0300 (6) | 0.0498 (7) | 0.0372 (6) | −0.0024 (4) | 0.0063 (5) | −0.0122 (5) |
Cl3 | 0.0291 (3) | 0.0340 (4) | 0.0461 (5) | 0.0009 (3) | 0.0050 (6) | 0.0031 (6) |
N1 | 0.0426 (12) | 0.0387 (14) | 0.0291 (13) | −0.0064 (11) | 0.007 (2) | −0.006 (2) |
C1—N1 | 1.493 (6) | C6—H6 | 0.9300 |
C1—H1A | 0.9600 | C7—C8 | 1.358 (6) |
C1—H1B | 0.9600 | C7—H7 | 0.9300 |
C1—H1C | 0.9600 | C8—C9 | 1.373 (7) |
C2—N1 | 1.501 (4) | C8—H8 | 0.9300 |
C2—H2A | 0.9600 | C9—C10 | 1.374 (7) |
C2—H2B | 0.9600 | C9—H9 | 0.9300 |
C2—H2C | 0.9600 | C10—H10 | 0.9300 |
C3—N1 | 1.463 (4) | Cd1—Cl1i | 2.6271 (12) |
C3—H3A | 0.9600 | Cd1—Cl2 | 2.6279 (13) |
C3—H3B | 0.9600 | Cd1—Cl3i | 2.6351 (8) |
C3—H3C | 0.9600 | Cd1—Cl3 | 2.6497 (8) |
C4—C5 | 1.489 (6) | Cd1—Cl1 | 2.6523 (13) |
C4—N1 | 1.509 (5) | Cd1—Cl2i | 2.6685 (13) |
C4—H4A | 0.9700 | Cd1—Cd1i | 3.3769 (7) |
C4—H4B | 0.9700 | Cl1—Cd1ii | 2.6271 (12) |
C5—C10 | 1.377 (6) | Cl2—Cd1ii | 2.6686 (13) |
C5—C6 | 1.389 (5) | Cl3—Cd1ii | 2.6351 (8) |
C6—C7 | 1.373 (5) | ||
N1—C1—H1A | 109.5 | C9—C10—H10 | 119.7 |
N1—C1—H1B | 109.5 | C5—C10—H10 | 119.7 |
H1A—C1—H1B | 109.5 | Cl1i—Cd1—Cl2 | 174.25 (5) |
N1—C1—H1C | 109.5 | Cl1i—Cd1—Cl3i | 83.49 (4) |
H1A—C1—H1C | 109.5 | Cl2—Cd1—Cl3i | 92.29 (4) |
H1B—C1—H1C | 109.5 | Cl1i—Cd1—Cl3 | 100.45 (4) |
N1—C2—H2A | 109.5 | Cl2—Cd1—Cl3 | 83.96 (4) |
N1—C2—H2B | 109.5 | Cl3i—Cd1—Cl3 | 175.25 (7) |
H2A—C2—H2B | 109.5 | Cl1i—Cd1—Cl1 | 92.79 (5) |
N1—C2—H2C | 109.5 | Cl2—Cd1—Cl1 | 84.05 (3) |
H2A—C2—H2C | 109.5 | Cl3i—Cd1—Cl1 | 99.83 (4) |
H2B—C2—H2C | 109.5 | Cl3—Cd1—Cl1 | 82.72 (4) |
N1—C3—H3A | 109.5 | Cl1i—Cd1—Cl2i | 83.75 (3) |
N1—C3—H3B | 109.5 | Cl2—Cd1—Cl2i | 99.70 (6) |
H3A—C3—H3B | 109.5 | Cl3i—Cd1—Cl2i | 83.45 (4) |
N1—C3—H3C | 109.5 | Cl3—Cd1—Cl2i | 94.28 (4) |
H3A—C3—H3C | 109.5 | Cl1—Cd1—Cl2i | 174.96 (5) |
H3B—C3—H3C | 109.5 | Cl1i—Cd1—Cd1i | 50.56 (3) |
C5—C4—N1 | 115.6 (3) | Cl2—Cd1—Cd1i | 128.77 (3) |
C5—C4—H4A | 108.4 | Cl3i—Cd1—Cd1i | 50.474 (17) |
N1—C4—H4A | 108.4 | Cl3—Cd1—Cd1i | 130.470 (19) |
C5—C4—H4B | 108.4 | Cl1—Cd1—Cd1i | 129.84 (3) |
N1—C4—H4B | 108.4 | Cl2i—Cd1—Cd1i | 49.86 (3) |
H4A—C4—H4B | 107.4 | Cl1i—Cd1—Cd1ii | 129.68 (3) |
C10—C5—C6 | 118.2 (4) | Cl2—Cd1—Cd1ii | 50.92 (3) |
C10—C5—C4 | 119.6 (4) | Cl3i—Cd1—Cd1ii | 128.963 (19) |
C6—C5—C4 | 122.2 (4) | Cl3—Cd1—Cd1ii | 50.092 (17) |
C7—C6—C5 | 120.7 (4) | Cl1—Cd1—Cd1ii | 49.91 (3) |
C7—C6—H6 | 119.6 | Cl2i—Cd1—Cd1ii | 130.45 (3) |
C5—C6—H6 | 119.6 | Cd1i—Cd1—Cd1ii | 179.436 (13) |
C8—C7—C6 | 120.3 (4) | Cd1ii—Cl1—Cd1 | 79.53 (4) |
C8—C7—H7 | 119.8 | Cd1—Cl2—Cd1ii | 79.22 (4) |
C6—C7—H7 | 119.8 | Cd1ii—Cl3—Cd1 | 79.43 (3) |
C7—C8—C9 | 119.8 (5) | C3—N1—C1 | 110.3 (5) |
C7—C8—H8 | 120.1 | C3—N1—C2 | 106.8 (3) |
C9—C8—H8 | 120.1 | C1—N1—C2 | 107.2 (4) |
C8—C9—C10 | 120.2 (5) | C3—N1—C4 | 111.3 (5) |
C8—C9—H9 | 119.9 | C1—N1—C4 | 110.6 (3) |
C10—C9—H9 | 119.9 | C2—N1—C4 | 110.5 (4) |
C9—C10—C5 | 120.7 (5) |
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) x−1/2, −y+1/2, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···Cl3iii | 0.96 | 2.74 | 3.600 (6) | 149 |
C3—H3B···Cl1iv | 0.96 | 2.83 | 3.586 (7) | 137 |
C4—H4A···Cl3 | 0.97 | 2.68 | 3.645 (5) | 171 |
Symmetry codes: (iii) x, y, z+1; (iv) x−1/2, −y+1/2, z+1. |
Experimental details
Crystal data | |
Chemical formula | (C10H16N)[CdCl3] |
Mr | 368.99 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 291 |
a, b, c (Å) | 6.7538 (14), 22.852 (5), 8.9590 (18) |
V (Å3) | 1382.7 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.13 |
Crystal size (mm) | 0.24 × 0.22 × 0.20 |
Data collection | |
Diffractometer | Rigaku Mercury2 diffractometer |
Absorption correction | Multi-scan (CrystalClear; Rigaku, 2005) |
Tmin, Tmax | 0.590, 0.650 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13516, 3167, 2743 |
Rint | 0.044 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.056, 1.06 |
No. of reflections | 3167 |
No. of parameters | 140 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.26, −0.41 |
Absolute structure | Flack (1983), with 1482 Bijvoet Pairs |
Absolute structure parameter | −0.07 (4) |
Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···Cl3i | 0.96 | 2.74 | 3.600 (6) | 149 |
C3—H3B···Cl1ii | 0.96 | 2.83 | 3.586 (7) | 137 |
C4—H4A···Cl3 | 0.97 | 2.68 | 3.645 (5) | 171 |
Symmetry codes: (i) x, y, z+1; (ii) x−1/2, −y+1/2, z+1. |
The understanding of ABX3-type perovskites remains one of the most challenging topics at the boundary between solid-state physics and solid-state chemistry. Perovskite materials exhibit many interesting and intriguing properties, from both the theoretical and application points of view. These compounds are used as sensors and catalyst electrodes in certain types of fuel cells and are candidates for memory devices and spintronics applications (Coey et al., 1999). It should be noted that a columnar arrangement is found frequently in ABX3-type compounds, which have been extensively studied because numerous crystal structures containing the methylammonium cation exhibit phase transitions related to the dynamics of the organic cations and inorganic anions (Doudin & Chapuis, 1992; Morosin, 1972; Puget et al., 1991; Waśkowska et al., 1990). Layered A2MX4 perovskites have attracted sustained interest because of their magnetic, electronic and other physical properties and the possibility of tuning both geometries and properties by variation of the organic cations (Gillon et al., 1999). Although perovskites have been known for a long time, new and intriguing physical effects are periodically discovered and their understanding remains an internationally highly competitive area. With these considerations in mind, we have used the benzyltrimethylammonium (Me3BzN+) cation to replace the N(CH3)4+ cation and have synthesized the title new one-dimensional ABX3-type organic–inorganic coordination polymer, (I).
The asymmetric unit of (I) consists of a trichlorocadmiate(II) anion and a Me3BzN+ cation, as shown in Fig. 1. The other three Cl anions (Cl1i, Cl2i and Cl3i) are produced by the corresponding Cl anions through the (1/2 + x, - y + 1/2, z) a-glide plane operation (Fig. 2). The CdII centres are hexacoordinated by chloride anions, giving a slightly distorted octahedral Cd(µ-Cl)6 arrangement. The Cd—Cl bond distances are in the range 2.6271 (12)–2.6685 (13) Å and the Cl—Cd—Cl bond angles are in the range 82.72 (4)–175.25 (7)°, deviating slightly from ideal octahedral angle values (90 and 180°). The octahedra are linked by two opposite shared faces, giving rise to infinite [Cd(µ-Cl)3-]∞ chains parallel to the a axis, with a Cd1···Cd1i distance of 3.3769 (7) Å and a Cd1i···Cd1···Cd1ii angle of 179.436 (14)° [symmetry codes: (i) x - 1/2, -y + 1/2, z; (ii) x + 1/2, -y + 1/2, z], indicating that the polymer is perfectly linear (Fig. 2). Thus, all halogen atoms act as bridges between two consecutive Cd atoms, and each pair of consecutive Cd atoms is linked by three corner-shared bridging chlorides. It should be noted that this columnar arrangement is found frequently in ABX3 compounds (Corradi et al., 1997; Costin-Hogan et al., 2008; Jian et al., 2006; López-Garzón et al., 1995; Ma et al., 2006; Maldonado et al., 2008). For example, the {[Cd3Cl9]3-}∞ anion reported by Jian et al. (2006) was also a one-dimensional inorganic chain, in which each CdII cation is octahedrally surrounded by six bridging Cl atoms, giving rise to polymeric chains. In the [NH(CH3)3]CdCl3 (TrMCd) compound reported by Chapuis & Zuniga (1980), the Cd atoms are located at the centres of face-sharing CdCl6 octahedra, forming infinite one-dimensional chains perpendicular to a hexagonal or nearly hexagonal net. The interchain distances are determined by the size of the organic cation which occupies the space between the octahedra, with a hydrogen bond between the alkylammonium cation and a Cl- anion.
There are thus three features in the structure of (I). Firstly, all the CdII cations are collinear. Secondly, the Cd1···Cd1 distance is much shorter than those reported in other one-dimensional cadmium polymers bridged by Cl atoms (average ca 4.14 Å) (Huang et al., 1998; Hu et al., 2003; Laskar et al., 2002). Although the Cd···Cd distance in complex (I) is larger than the interatomic distance in bulk Cd (2.98 Å; Stuhlmann et al., 1998), it is still shorter than the 115% total sum of Cd metal radii (3.427 Å; Standard reference?). There seems to be no good theoretically supported argument for the existence of a Cd—Cd metal bond in (I) (Bender et al., 1985). Finally, the Me3BzN+ cations on each side of the inorganic chain are arranged in a zigzag configuration. The charges of the cations are balanced by the polymeric [Cd(µ-Cl)3-]∞ anion. The Me3BzN+ cations are located in the inter-chain space with non-covalent static attracting forces (Coulomb and van der Waals forces) and non-classical C—H···Cl hydrogen-bond interactions with the anionic chains to stabilize the crystal structure (Table 1, Fig. 2). The bond lengths and angles of the Me3BzN+ cations are in agreement with those reported in the literature (Müller et al., 1994; Hauge & Maroy, 1996).
Our interest in one-dimensional ABX3-type organic–inorganic hybrid complexes is based mainly on their potential uses in molecular dielectrics and ferroelectrics. The variable-temperature dielectric response, especially in the relatively high-frequency range, is very useful in the search for phase transitions (Wu et al., 2011; Wu & Jin, 2012). However, we were unable to detect any dielectric anomalies within the temperature range 93–460 K when we measured the dielectric properties of (I) with temperature, implying that there are no structural phase transitions within that temperature range and that (I) may not have ferroelectric properties (Ye et al., 2009; Fu et al., 2007). Further ABX3-type ferroelectrics still need to be sought and studied.