Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270105038035/bc1084sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270105038035/bc1084Isup2.hkl |
Iron(III) hypophosphite was synthesized by the reaction of equimolar quantities of iron powder and 100% hypophosphoric acid in air at room temperature. A precipitate formed when about 70% of the iron powder was taken into the reaction (about 2 days). The mixture was filtered and left to stand in air. Powder formed at the bottom of the beaker and crystals appeared in the meniscus. The powder X-ray pattern of the bulk product is in good agreement with the calculated pattern. Iron(III) hypophosphite is almost insoluble in water.
H atoms were located in difference electron density maps and included in the refinement without any constraints.
Previous crystal structure investigations of anhydrous salts of hypophosphoric acid include NH4H2PO2 (Zachariasen & Mooney, 1934), Ca(H2PO2)2 (GoedkooP1 & Loopstra, 1959), CaNa(H2PO2)3 (Matsuzaki & Iitaka, 1969), Zn(H2PO2)2 (Weakley, 1979; Tanner et al., 1997), La(H2PO2)3 (Tanner et al., 1999), Er(H2PO2)3 (Aslanov et al., 1975), Ge2(H2PO2)6 (Weakley, 1983) and U(H2PO2)4 (Tanner et al., 1992). It is evident that the investigation of this type of compound is incomplete and the limited number of studies is probably a result of the difficulty of preparation and crystal growth. Our own crystallographic studies on anhydrous hypophosphites include Cu(H2PO2)2 (Naumov et al., 2002), MH2PO2 (M = K, Rb and Cs; Naumova et al., 2004), LiH2PO2 and Be(H2PO2)2 (Naumov et al., 2004), and M(H2PO2)2 (M = Sr, Ba and Pb; Kuratieva et al., 2005).
All bivalent metal hypophosphites adopt layered structures. Rare-earth hypophosphites adopt layered structures, as in Er(H2PO2)3 (Aslanov et al., 1975), or three-dimentional network structures, as in La(H2PO2)3 (Tanner et al., 1999). In contrast, the structure of Fe(H2PO2)3 consists of chains formed by hypophosphite anions and iron cations, the latter being coordinated by six hypophosphite O atoms forming a nearly ideal octahedral environment for both Fe3+ cations (Fig. 1). The structure is isotypical to that of the GeIIGeIV hypophosphite in which, however, the two Ge atoms have different coordination spheres (Weakley, 1983). The chains are parallel to the c axis and linked together via van der Waals interactions, with short H···H contacts of 2.35 (2) and 2.56 (2) Å.
Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Bruker, 2004); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and BS (Ozawa & Kang, 2004); software used to prepare material for publication: SHELXTL.
Fig. 1. A [001] chain in the structure of Fe(H2PO2)3. Displacement ellipsoids are plotted at the 50% probability level and H atoms are drawn as small spheres of arbitrary radii. |
Fe(H2PO2)3 | Dx = 2.353 Mg m−3 |
Mr = 250.81 | Mo Kα radiation, λ = 0.71073 Å |
Hexagonal, R3 | Cell parameters from 521 reflections |
Hall symbol: -R 3 | θ = 3.6–28.2° |
a = 11.2800 (11) Å | µ = 2.78 mm−1 |
c = 9.6375 (11) Å | T = 293 K |
V = 1061.97 (19) Å3 | Prism, colourless |
Z = 6 | 0.08 × 0.04 × 0.02 mm |
F(000) = 750 |
Bruker–Nonius X8 APEX CCD area-detector diffractometer | 430 independent reflections |
Radiation source: fine-focus sealed tube | 361 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
Detector resolution: 25 pixels mm-1 | θmax = 25.3°, θmin = 3.6° |
φ scans | h = −13→7 |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | k = −5→13 |
Tmin = 0.808, Tmax = 0.947 | l = −11→11 |
1147 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.030 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.073 | All H-atom parameters refined |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0377P)2] where P = (Fo2 + 2Fc2)/3 |
430 reflections | (Δ/σ)max < 0.001 |
40 parameters | Δρmax = 0.46 e Å−3 |
2 restraints | Δρmin = −0.39 e Å−3 |
Fe(H2PO2)3 | Z = 6 |
Mr = 250.81 | Mo Kα radiation |
Hexagonal, R3 | µ = 2.78 mm−1 |
a = 11.2800 (11) Å | T = 293 K |
c = 9.6375 (11) Å | 0.08 × 0.04 × 0.02 mm |
V = 1061.97 (19) Å3 |
Bruker–Nonius X8 APEX CCD area-detector diffractometer | 430 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | 361 reflections with I > 2σ(I) |
Tmin = 0.808, Tmax = 0.947 | Rint = 0.034 |
1147 measured reflections |
R[F2 > 2σ(F2)] = 0.030 | 2 restraints |
wR(F2) = 0.073 | All H-atom parameters refined |
S = 1.03 | Δρmax = 0.46 e Å−3 |
430 reflections | Δρmin = −0.39 e Å−3 |
40 parameters |
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 | ||
Fe1 | 0.0000 | 0.0000 | 0.0000 | 0.0184 (3) | |
Fe2 | 0.0000 | 0.0000 | 0.5000 | 0.0204 (4) | |
P1 | 0.18791 (9) | 0.20062 (9) | 0.24457 (9) | 0.0190 (3) | |
O1 | 0.1648 (2) | 0.1143 (2) | 0.1173 (2) | 0.0249 (6) | |
O2 | 0.1596 (2) | 0.1276 (3) | 0.3822 (2) | 0.0285 (6) | |
H1 | 0.322 (2) | 0.305 (2) | 0.247 (3) | 0.020 (9)* | |
H2 | 0.106 (3) | 0.258 (3) | 0.227 (3) | 0.015 (8)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Fe1 | 0.0242 (5) | 0.0242 (5) | 0.0067 (6) | 0.0121 (2) | 0.000 | 0.000 |
Fe2 | 0.0278 (5) | 0.0278 (5) | 0.0055 (6) | 0.0139 (2) | 0.000 | 0.000 |
P1 | 0.0219 (5) | 0.0206 (5) | 0.0124 (5) | 0.0090 (4) | −0.0011 (4) | −0.0012 (4) |
O1 | 0.0289 (13) | 0.0339 (15) | 0.0128 (13) | 0.0164 (12) | −0.0045 (10) | −0.0069 (11) |
O2 | 0.0307 (14) | 0.0354 (16) | 0.0143 (14) | 0.0126 (12) | 0.0022 (10) | 0.0031 (11) |
Fe1—O1 | 2.000 (2) | Fe2—O2v | 2.003 (2) |
Fe1—O1i | 2.000 (2) | Fe2—O2vii | 2.003 (2) |
Fe1—O1ii | 2.000 (2) | Fe2—O2iii | 2.003 (2) |
Fe1—O1iii | 2.000 (2) | Fe2—O2viii | 2.003 (2) |
Fe1—O1iv | 2.000 (2) | P1—O1 | 1.506 (2) |
Fe1—O1v | 2.000 (2) | P1—O2 | 1.509 (2) |
Fe2—O2 | 2.003 (2) | P1—H1 | 1.38 (4) |
Fe2—O2vi | 2.003 (2) | P1—H2 | 1.38 (4) |
O1—Fe1—O1i | 180 | O2v—Fe2—O2iii | 91.04 (9) |
O1i—Fe1—O1ii | 91.17 (9) | O2vii—Fe2—O2iii | 180 |
O1—Fe1—O1ii | 88.83 (9) | O2vi—Fe2—O2 | 88.96 (9) |
O1i—Fe1—O1iii | 88.83 (9) | O2v—Fe2—O2 | 91.04 (9) |
O1—Fe1—O1iii | 91.17 (9) | O2vii—Fe2—O2 | 88.96 (9) |
O1ii—Fe1—O1iii | 180 | O2iii—Fe2—O2 | 91.04 (9) |
O1i—Fe1—O1iv | 91.17 (9) | O2vi—Fe2—O2viii | 91.04 (9) |
O1—Fe1—O1iv | 88.83 (9) | O2v—Fe2—O2viii | 88.96 (9) |
O1ii—Fe1—O1iv | 91.17 (9) | O2vii—Fe2—O2viii | 91.04 (9) |
O1iii—Fe1—O1iv | 88.83 (9) | O2iii—Fe2—O2viii | 88.96 (9) |
O1i—Fe1—O1v | 88.83 (9) | O2—Fe2—O2viii | 180 |
O1—Fe1—O1v | 91.17 (9) | O1—P1—O2 | 116.25 (15) |
O1ii—Fe1—O1v | 88.83 (9) | O1—P1—H1 | 109.0 (13) |
O1iii—Fe1—O1v | 91.17 (9) | O2—P1—H1 | 107.1 (14) |
O1iv—Fe1—O1v | 180 | O1—P1—H2 | 105.2 (13) |
O2vi—Fe2—O2v | 180 | O2—P1—H2 | 111.0 (12) |
O2vi—Fe2—O2vii | 91.04 (9) | H1—P1—H2 | 108 (2) |
O2v—Fe2—O2vii | 88.96 (9) | P1—O1—Fe1 | 133.01 (15) |
O2vi—Fe2—O2iii | 88.96 (9) | P1—O2—Fe2 | 139.42 (15) |
Symmetry codes: (i) −x, −y, −z; (ii) y, −x+y, −z; (iii) −y, x−y, z; (iv) x−y, x, −z; (v) −x+y, −x, z; (vi) x−y, x, −z+1; (vii) y, −x+y, −z+1; (viii) −x, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | Fe(H2PO2)3 |
Mr | 250.81 |
Crystal system, space group | Hexagonal, R3 |
Temperature (K) | 293 |
a, c (Å) | 11.2800 (11), 9.6375 (11) |
V (Å3) | 1061.97 (19) |
Z | 6 |
Radiation type | Mo Kα |
µ (mm−1) | 2.78 |
Crystal size (mm) | 0.08 × 0.04 × 0.02 |
Data collection | |
Diffractometer | Bruker–Nonius X8 APEX CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2004) |
Tmin, Tmax | 0.808, 0.947 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1147, 430, 361 |
Rint | 0.034 |
(sin θ/λ)max (Å−1) | 0.602 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.073, 1.03 |
No. of reflections | 430 |
No. of parameters | 40 |
No. of restraints | 2 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.46, −0.39 |
Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SAINT, SHELXTL (Bruker, 2004), SHELXTL and BS (Ozawa & Kang, 2004).
Fe1—O1 | 2.000 (2) | P1—O2 | 1.509 (2) |
Fe2—O2 | 2.003 (2) | P1—H1 | 1.38 (4) |
P1—O1 | 1.506 (2) | P1—H2 | 1.38 (4) |
O1—Fe1—O1i | 180 | O1—P1—O2 | 116.25 (15) |
O1—Fe1—O1ii | 91.17 (9) | H1—P1—H2 | 108 (2) |
Symmetry codes: (i) −x, −y, −z; (ii) −y, x−y, z. |
Previous crystal structure investigations of anhydrous salts of hypophosphoric acid include NH4H2PO2 (Zachariasen & Mooney, 1934), Ca(H2PO2)2 (GoedkooP1 & Loopstra, 1959), CaNa(H2PO2)3 (Matsuzaki & Iitaka, 1969), Zn(H2PO2)2 (Weakley, 1979; Tanner et al., 1997), La(H2PO2)3 (Tanner et al., 1999), Er(H2PO2)3 (Aslanov et al., 1975), Ge2(H2PO2)6 (Weakley, 1983) and U(H2PO2)4 (Tanner et al., 1992). It is evident that the investigation of this type of compound is incomplete and the limited number of studies is probably a result of the difficulty of preparation and crystal growth. Our own crystallographic studies on anhydrous hypophosphites include Cu(H2PO2)2 (Naumov et al., 2002), MH2PO2 (M = K, Rb and Cs; Naumova et al., 2004), LiH2PO2 and Be(H2PO2)2 (Naumov et al., 2004), and M(H2PO2)2 (M = Sr, Ba and Pb; Kuratieva et al., 2005).
All bivalent metal hypophosphites adopt layered structures. Rare-earth hypophosphites adopt layered structures, as in Er(H2PO2)3 (Aslanov et al., 1975), or three-dimentional network structures, as in La(H2PO2)3 (Tanner et al., 1999). In contrast, the structure of Fe(H2PO2)3 consists of chains formed by hypophosphite anions and iron cations, the latter being coordinated by six hypophosphite O atoms forming a nearly ideal octahedral environment for both Fe3+ cations (Fig. 1). The structure is isotypical to that of the GeIIGeIV hypophosphite in which, however, the two Ge atoms have different coordination spheres (Weakley, 1983). The chains are parallel to the c axis and linked together via van der Waals interactions, with short H···H contacts of 2.35 (2) and 2.56 (2) Å.