NH₄PbI₃

Single crystals of ammonium lead iodide, NH₄PbI₃, have been obtained by solid-state reactions. Each Pb^II ion is coordinated by six I^- ions in a distorted octa­hedral environment. PbI₆ octa­hedra are connected by common edges, forming a one-dimensional anion chain. All atoms except one H atom in a general position have site symmetry m.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](b-I) = 0.001 Å
• R factor = 0.033
• wR factor = 0.083
• Data-to-parameter ratio = 27.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N1     -   H2     ...          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N1     -   H3     ...          ?
PLAT732_ALERT_1_C Angle   Calc     109(11), Rep      108(5) ......       2.20 su-Ra
              H1   -N1   -H2      1.555   1.555   1.555
PLAT732_ALERT_1_C Angle   Calc      109(7), Rep      109(3) ......       2.33 su-Ra
              H1   -N1   -H3      1.555   1.555   1.555
PLAT732_ALERT_1_C Angle   Calc      110(7), Rep      110(3) ......       2.33 su-Ra
              H2   -N1   -H3      1.555   1.555   1.555

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT794_ALERT_5_G Check Predicted Bond Valency for Pb1         (2)       2.12
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          9

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

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

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S1. Comment

Considerable current interests focus on fundamental as well as more applied studies of iodoplumbates related to their significant structural, electrical, non-linear optical, and other physical properties (Mitzi et al., 1995; Guloy et al., 2001; Fan et al., 2006). Lead(II) iodide and its low-dimensional derivatives represent a potential class of functional materials. We report here the crystal structure of the title lead(II) iodide complex, which has a one-dimensional anion chain.

There is one crystallographically independent Pb^II ion in the asymmetric unit (Fig. 1). Pb^II ion is six-coordinated in a distorted octahedral environment by six I^- ions with Pb—I distances ranging from 3.0595 (9) to 3.3679 (9) Å and cis I—Pb—I angles from 84.40 (2) to 94.78 (2)° (Table 1). Adjacent octahedra are joined by a common edge (I1/I3) to form a chain; two neighboring chains are connected through a common edge (I1/I1) to form a one-dimensional anion chain [PbI₃]_n^n– along the b axis (Fig. 2). As a consequence of the connectivity of PbI₆ octahedra, the I^- ions are acting as µ₃ (I1) and µ bridge (I3) and as a terminal ligand (I2). The longest Pb—I bond length is observed for the triply bridging ligand I1 due to its higher connectivity and the trans influence of the terminal ligand I2 in trans position to I2 (Krautscheid, et al., 2001). At 473 K, the C—N bonds of [Bu₄N]⁺ are broken, so the cation of [NH₄]⁺ is formed. The anion chain has no significant hydrogen-bonding interactions with the cations.

Related literature

For related literature, see: Fan, Chen & Wu (2006); Fan, Wu & Chen (2006); Guloy et al. (2001); Krautscheid et al. (2001); Mitzi et al. (1995).

S2. Experimental

A mixture of PbI₂ (92 mg, 0.2 mmol) and Bu₄NI (74 mg, 0.2 mmol) was pressed into a pellet, which was then sealed into an evacuated quartz tube. The quartz tube was heated at 473 K for 2 days, and then cooled slowly to room temperature. Prism-shaped yellow crystals of suitable for X-ray analysis were obtained.

S3. Refinement

The N—H distances were restrained to 0.80 (2) Å. The displacement parameters of H atoms were set at 1.5 times U_eq of the N atom. The highest peak is located 1.17 Å from I1 and the deepest hole is located 0.74 Å from Pb1.

Computing details

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear (Rigaku, 2000); data reduction: CrystalClear (Rigaku, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL (Bruker, 1998).

Figures

Fig. 1. The asymmetric uni of (I), together with additional I atoms to complete the coordination of Pb atom. Displacement ellipsoids are plotted at the 50% probability level. [Symmetry code: (A) x, 1 + y, z; (B) 1 – x, 1 – y, 1 – z, (C) x, – 0.5 – y, z]

ammonium lead iodide

Crystal data

NH4PbI3	F(000) = 1008
Mr = 605.94	Dx = 4.766 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 2002 reflections
a = 10.3029 (14) Å	θ = 3.1–27.5°
b = 4.7411 (5) Å	µ = 30.84 mm^−1
c = 17.288 (2) Å	T = 293 K
V = 844.48 (18) Å^3	Prism, yellow
Z = 4	0.10 × 0.08 × 0.05 mm

Data collection

Rigaku Mercury CCD diffractometer	1080 independent reflections
Radiation source: Sealed Tube	1012 reflections with I > 2σ(I)
Graphite Monochromator monochromator	Rint = 0.045
ω scans	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2000)	h = −12→13
Tmin = 0.064, Tmax = 0.214	k = −6→6
6247 measured reflections	l = −22→17

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)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.083	Only H-atom coordinates refined
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0484P)^2 + 2.6931P] where P = (Fo^2 + 2Fc^2)/3
1080 reflections	(Δ/σ)max < 0.001
39 parameters	Δρmax = 1.11 e Å^−3
9 restraints	Δρmin = −1.78 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 > 2σ(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
Pb1	0.66816 (4)	0.7500	0.44155 (2)	0.02949 (16)
I1	0.47613 (7)	0.2500	0.38364 (4)	0.0303 (2)
I2	0.80933 (8)	0.7500	0.28586 (5)	0.0401 (2)
I3	0.84262 (7)	0.2500	0.51297 (5)	0.0374 (2)
N1	0.9132 (13)	−0.2500	0.6757 (6)	0.053 (4)
H1	0.952 (12)	−0.2500	0.715 (5)	0.080*
H2	0.963 (11)	−0.2500	0.641 (6)	0.080*
H3	0.871 (5)	−0.115 (12)	0.674 (5)	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pb1	0.0328 (3)	0.0274 (3)	0.0283 (3)	0.000	0.00360 (17)	0.000
I1	0.0298 (4)	0.0360 (4)	0.0250 (4)	0.000	−0.0016 (3)	0.000
I2	0.0453 (5)	0.0413 (5)	0.0336 (4)	0.000	0.0133 (4)	0.000
I3	0.0326 (4)	0.0293 (4)	0.0503 (5)	0.000	−0.0092 (3)	0.000
N1	0.071 (9)	0.053 (8)	0.036 (6)	0.000	−0.001 (6)	0.000

Geometric parameters (Å, º)

Pb1—I2	3.0595 (9)	I1—Pb1^iii	3.2459 (6)
Pb1—I3^i	3.2210 (6)	I1—Pb1^ii	3.3679 (9)
Pb1—I3	3.2210 (6)	I3—Pb1^iii	3.2210 (6)
Pb1—I1	3.2459 (6)	N1—H1	0.79 (7)
Pb1—I1^i	3.2459 (6)	N1—H2	0.78 (7)
Pb1—I1^ii	3.3679 (9)	N1—H3	0.78 (6)
I2—Pb1—I3^i	94.12 (2)	I3^i—Pb1—I1^ii	84.40 (2)
I2—Pb1—I3	94.12 (2)	I3—Pb1—I1^ii	84.40 (2)
I3^i—Pb1—I3	94.78 (2)	I1—Pb1—I1^ii	90.443 (18)
I2—Pb1—I1	91.05 (2)	I1^i—Pb1—I1^ii	90.443 (18)
I3^i—Pb1—I1	174.78 (2)	Pb1—I1—Pb1^iii	93.83 (2)
I3—Pb1—I1	85.461 (16)	Pb1—I1—Pb1^ii	89.557 (18)
I2—Pb1—I1^i	91.05 (2)	Pb1^iii—I1—Pb1^ii	89.557 (18)
I3^i—Pb1—I1^i	85.461 (16)	Pb1^iii—I3—Pb1	94.78 (2)
I3—Pb1—I1^i	174.78 (2)	H1—N1—H2	108 (5)
I1—Pb1—I1^i	93.83 (2)	H1—N1—H3	109 (3)
I2—Pb1—I1^ii	177.81 (3)	H2—N1—H3	110 (3)
I2—Pb1—I1—Pb1^iii	88.87 (2)	I1^i—Pb1—I1—Pb1^ii	−90.474 (19)
I3—Pb1—I1—Pb1^iii	−5.18 (2)	I1^ii—Pb1—I1—Pb1^ii	0.0
I1^i—Pb1—I1—Pb1^iii	180.0	I2—Pb1—I3—Pb1^iii	−85.50 (2)
I1^ii—Pb1—I1—Pb1^iii	−89.526 (19)	I3^i—Pb1—I3—Pb1^iii	180.0
I2—Pb1—I1—Pb1^ii	178.399 (19)	I1—Pb1—I3—Pb1^iii	5.23 (2)
I3—Pb1—I1—Pb1^ii	84.34 (2)	I1^ii—Pb1—I3—Pb1^iii	96.12 (2)

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