1,1,1,2,2-Penta­iodo­diphosphanium tetra­iodo­gallate(III)

1,1,1,2,2-Penta­iodo­diphosphanium tetra­iodo­gallate(III), (P₂I₅)[GaI₄], crystallizes in the orthorhombic space group Pbca. The structure is isotypic with (P₂I₅)[AlI₄]. Short I...I interatomic distances indicate weak interactions between cations and anions.

Key indicators

• Single-crystal X-ray study
• T = 200 K
• Mean [sigma](I-Ga) = 0.001 Å
• R factor = 0.027
• wR factor = 0.076
• Data-to-parameter ratio = 28.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level B:



THETM_01  Alert B The value of sine(theta_max)/wavelength is less than 0.575
          Calculated sin(theta_max)/wavelength =    0.5723

Author response: Image plate distance was 80 mm because of the cell dimensions, so theta_max=24.2\%. The value of sine (theta_max) /wavelength could be more than 0.575.

 0 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 0 Alert Level C = Please check

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S1. Comment

The 2:1 adduct of PI₃ and AlI₃ was structurally characterized by X-ray crystallography and identified as (P₂I₅)[AlI₄] (Pohl, 1983). Recently, the 1,1,1,2,2-pentaiododiphosphanium cation species (P₂I₅)[EI₄] (E = Al, Ga, In) have been characterized by solid-state ³¹P MAS NMR and vibrational spectroscopy (Aubauer et al., 1999). The crystal structure of (P₂I₅)[GaI₄] is isotypic with the structure found for (P₂I₅)[AlI₄]. The P1—P2 bond distance is comparable with the P—P bond length of 2.218 (13) Å in (P₂I₅)[AlI₄] (Pohl, 1983) and 2.230 (3) Å in P₂I₄ (Zak & Cernik, 1996). The P₂I₅⁺ cation displays a staggered configuration (Fig. 1), with an I1—P1—P2—I4 torsion angle of -52.3 (1)°. The P2—I4 and P2—I5 bond lengths of the PI₂ unit are significantly longer than the P1—I1, P1—I2 and P1—I3 bond lengths found for the PI₃ unit. The GaI₄^- unit has a slightly distorted tetrahedral geometry. The Ga—I bond distances range between 2.521 (1) and 2.577 (1) Å, and the I—Ga—I bond angles between 105.15 (4) and 112.18 (4)°, similar to the bond lenghts and angles found in (TeI₃)[GaI₄] (Schulz-Lang et al., 1998). Similar to (P₂I₅)[AlI₄] (Pohl, 1983), the structure of (P₂I₅)[GaI₄] shows weak interatomic I···I distances in the range 3.4002 (8)–3.9168 (8) Å between the P₂I₅⁺ and the GaI₄^- units (Fig. 2), which are significantly shorter than the sum of the van der Waals radii (ca 4.3 Å), indicating weak cation–anion interactions.

S2. Experimental

(P₂I₅)[GaI₄] was prepared by the reaction of PI₃ (0.84 g, 2.00 mmol) and GaI₃ (0.45 g, 1.00 mmol) in CS₂ (20 ml) at room temperature. The solvent was slowly removed under static vacuum, yielding red crystals.

Computing details

Data collection: IPDS Software Manual (Stoe, 1997); cell refinement: IPDS Software Manual; data reduction: IPDS Software Manual; program(s) used to solve structure: SIR97 (Cascarano et al., 1996); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997). SCHAKAL (Keller, 1995) and DIAMOND (Bergerhoff, 1996); software used to prepare material for publication: PLATON (Spek, 1990).

Figures

	Fig. 1. The molecular structure of (P2I5)[GaI4] showing 50% probability displacement ellipsoids.
	Fig. 2. Packing diagram viewed down the a axis.

1,1,1,2,2-Pentaiododiphosphanium tetraiodogallate(III)

Crystal data

(P2I5)[GaI4]	Orthorhombic P (as derived from metrics)
Mr = 1273.81	Dx = 4.273 (1) Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 5000 reflections
a = 10.7960 (5) Å	θ = 2.4–24.0°
b = 18.1687 (8) Å	µ = 15.55 mm^−1
c = 20.1886 (10) Å	T = 200 K
V = 3960.0 (3) Å^3	Irregular, red
Z = 8	0.19 × 0.12 × 0.10 mm
F(000) = 4304

Data collection

Stoe IPDS diffractometer	3094 independent reflections
Radiation source: fine-focus sealed tube	2570 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.097
area detection scans	θmax = 24.0°, θmin = 2.4°
Absorption correction: numerical crystal faces optimized with Stoe X-SHAPE (Stoe, 1997) then a numerical absorption correction with X-RED (revision 1.09; Stoe, 1997)	h = −12→12
Tmin = 0.194, Tmax = 0.395	k = −16→20
10907 measured reflections	l = −19→23

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.027	Secondary atom site location: difference Fourier map
wR(F^2) = 0.076	w = 1/[σ^2(Fo^2) + (0.035P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.96	(Δ/σ)max = 0.001
3094 reflections	Δρmax = 1.38 (0.82 Å from I3) e Å^−3
109 parameters	Δρmin = −1.23 (0.90 Å from I3) e Å^−3

Special details

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
Ga	0.13672 (8)	0.21858 (5)	0.11901 (4)	0.0215 (2)
I6	−0.00354 (5)	0.20184 (3)	0.21770 (3)	0.03203 (16)
I7	0.29375 (5)	0.11255 (3)	0.10729 (3)	0.02884 (16)
I8	0.01101 (6)	0.22888 (3)	0.01348 (3)	0.03364 (16)
I9	0.26802 (5)	0.33435 (3)	0.13418 (3)	0.02882 (16)
P1	0.8024 (2)	0.49494 (11)	0.12882 (11)	0.0224 (5)
P2	0.6664 (2)	0.42147 (12)	0.07874 (11)	0.0239 (5)
I1	0.75379 (5)	0.53586 (3)	0.23890 (3)	0.03010 (16)
I2	0.99534 (5)	0.42794 (3)	0.13111 (3)	0.03039 (16)
I3	0.82519 (6)	0.60032 (4)	0.05889 (4)	0.0455 (2)
I4	0.65420 (6)	0.33280 (3)	0.16800 (3)	0.03460 (17)
I5	0.48824 (5)	0.50114 (3)	0.09895 (3)	0.03056 (16)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ga	0.0243 (5)	0.0210 (4)	0.0193 (5)	0.0012 (4)	0.0003 (4)	0.0014 (4)
I6	0.0364 (3)	0.0306 (3)	0.0291 (3)	−0.0061 (3)	0.0121 (3)	−0.0023 (3)
I7	0.0291 (3)	0.0288 (3)	0.0286 (3)	0.0093 (2)	0.0024 (2)	0.0051 (3)
I8	0.0420 (4)	0.0345 (3)	0.0245 (3)	0.0055 (3)	−0.0107 (3)	0.0008 (3)
I9	0.0227 (3)	0.0270 (3)	0.0368 (3)	−0.0035 (2)	0.0042 (3)	−0.0007 (3)
P1	0.0243 (11)	0.0216 (11)	0.0213 (11)	−0.0011 (8)	0.0014 (9)	0.0023 (10)
P2	0.0293 (11)	0.0270 (11)	0.0154 (10)	−0.0014 (9)	−0.0003 (9)	−0.0029 (10)
I1	0.0358 (3)	0.0307 (3)	0.0238 (3)	0.0023 (2)	−0.0058 (3)	−0.0072 (3)
I2	0.0254 (3)	0.0246 (3)	0.0412 (4)	0.0018 (2)	0.0021 (3)	−0.0007 (3)
I3	0.0445 (4)	0.0377 (4)	0.0543 (5)	0.0032 (3)	0.0106 (3)	0.0234 (3)
I4	0.0455 (4)	0.0274 (3)	0.0309 (3)	−0.0066 (3)	−0.0070 (3)	0.0077 (3)
I5	0.0276 (3)	0.0322 (3)	0.0319 (3)	0.0000 (2)	−0.0019 (2)	0.0023 (3)

Geometric parameters (Å, º)

Ga—I6	2.5210 (10)	P1—I3	2.391 (2)
Ga—I8	2.5330 (10)	P1—I1	2.401 (2)
Ga—I9	2.5549 (10)	P1—I2	2.413 (2)
Ga—I7	2.5771 (10)	P2—I4	2.421 (2)
P1—P2	2.227 (3)	P2—I5	2.442 (2)
I1···I7^i	3.4420 (9)	I4···I6^iii	3.7264 (8)
I2···I9^ii	3.4002 (8)	I5···I7^iv	3.6598 (8)
I6—Ga—I8	110.60 (4)	I3—P1—I1	108.72 (8)
I6—Ga—I9	109.75 (4)	P2—P1—I2	105.98 (10)
I8—Ga—I9	109.71 (4)	I3—P1—I2	109.04 (9)
I6—Ga—I7	112.18 (4)	I1—P1—I2	109.09 (9)
I8—Ga—I7	109.30 (4)	P1—P2—I4	95.56 (10)
I9—Ga—I7	105.15 (4)	P1—P2—I5	95.05 (10)
P2—P1—I3	106.25 (11)	I4—P2—I5	103.13 (9)
P2—P1—I1	117.50 (11)
I3—P1—P2—I4	−174.24 (8)	I3—P1—P2—I5	−70.48 (10)
I1—P1—P2—I4	−52.33 (12)	I1—P1—P2—I5	51.43 (12)
I2—P1—P2—I4	69.85 (10)	I2—P1—P2—I5	173.61 (8)

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