Bismuth(V) iron(III) tris(phosphate) oxide

Bi^V_0.4Fe₃^IIIO(PO₄)₃ crystallizes with two Fe atoms (one on an inversion centre and one on a mirror plane) displaying octahedral geometry and a third Fe atom (on a mirror plane) with trigonal bipyramidal coordination. Fe atoms are seen in oxy­gen-bridged chains. Bi^V atoms are found in the interstitial sites between these chains. Bi shows sevenfold coordination, with Bi-O distances between 2.357 (7) and 2.529 (6) Å.

Computing details

Data collection: XSCANS (Siemens, 1991); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1990b).

Bismuth(V) iron(III) tris(phosphate) oxide

Crystal data

Bi0.4Fe3O(PO4)3	F(000) = 520.4
Mr = 552.04	Dx = 3.890 Mg m^−3
Monoclinic, P21/m	Mo Kα radiation, λ = 0.71073 Å
a = 7.496 (1) Å	Cell parameters from 35 reflections
b = 6.308 (1) Å	θ = 8.5–13.2°
c = 10.125 (2) Å	µ = 12.58 mm^−1
β = 100.11 (1)°	T = 293 K
V = 471.32 (13) Å^3	Chunk, red
Z = 2	0.1 × 0.1 × 0.1 mm

Data collection

Syntex P4 four-circle diffractometer	867 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.088
Graphite monochromator	θmax = 30°, θmin = 2.8°
θ/2θ scans	h = −1→10
Absorption correction: ψ-scan (XEMP; Siemens, 1990a)	k = −1→8
Tmin = 0.244, Tmax = 0.284	l = −14→14
2030 measured reflections	3 standard reflections every 97 reflections
1468 independent reflections	intensity decay: 0.0%

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)] = 0.058	Calculated w = 1/[σ^2(Fo^2) + (0.0435P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.128	(Δ/σ)max = 0.056
S = 0.84	Δρmax = 0.25 e Å^−3
1468 reflections	Δρmin = −0.72 e Å^−3
115 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0000 (19)

Special details

Experimental. We have identified the heavy atom occupants of the metallic sites by refining their occupancy factors in a prefinal refinement. This has enabled us to establish the identities of the metals in each location and also to eliminate the possibility of shared sites. The anisotropy of O1 reflects a disorder of this position about the mirror plane and thus the 'looseness' with which the oxo-O atom is bound in the solid. A variable scan rate was used, in a θ/2θ scan mode with a scan width of 0.6° below Kα₁ and 0.6° above Kα₂ to a maximum 2θ value of 50°.

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.

Refinement was completed using full-matrix least-squares methods.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Bi1	0.6591 (2)	1/4	0.19371 (15)	0.0114 (5)	0.40 (3)
Fe1	0	0	0	0.0070 (4)
Fe2	0.6496 (2)	1/4	−0.20185 (16)	0.0060 (4)
Fe3	0.2143 (2)	1/4	−0.43654 (16)	0.0081 (4)
O1	0.8762 (11)	1/4	−0.0928 (7)	0.0088 (16)
P1	0.7834 (4)	1/4	0.5116 (3)	0.0072 (6)
O11	0.9749 (10)	1/4	0.5901 (8)	0.0120 (18)
O12	0.6511 (11)	1/4	0.6076 (8)	0.0129 (18)
O13	0.7512 (8)	0.0608 (9)	0.4154 (5)	0.0113 (12)
P2	0.3173 (4)	1/4	−0.1129 (3)	0.0061 (6)
O21	0.3585 (10)	1/4	−0.2563 (7)	0.0060 (15)
O22	0.5078 (11)	1/4	−0.0310 (7)	0.0091 (16)
O23	0.2109 (7)	0.0486 (9)	−0.0936 (5)	0.0088 (12)
P3	0.2634 (4)	1/4	0.2394 (3)	0.0064 (6)
O31	0.2150 (12)	1/4	0.3744 (8)	0.0161 (19)
O32	0.0829 (10)	1/4	0.1343 (7)	0.0083 (16)
O33	0.3797 (7)	0.4374 (9)	0.2129 (5)	0.0093 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Bi1	0.0118 (8)	0.0106 (9)	0.0121 (8)	0	0.0033 (6)	0
Fe1	0.0078 (7)	0.0038 (7)	0.0098 (8)	−0.0015 (6)	0.0030 (6)	−0.0002 (6)
Fe2	0.0051 (7)	0.0052 (8)	0.0078 (7)	0	0.0018 (6)	0
Fe3	0.0107 (8)	0.0064 (8)	0.0074 (8)	0	0.0020 (6)	0
O1	0.013 (4)	0.008 (4)	0.003 (3)	0	−0.004 (3)	0
P1	0.0109 (13)	0.0045 (13)	0.0075 (13)	0	0.0051 (11)	0
O11	0.009 (4)	0.015 (5)	0.011 (4)	0	−0.002 (3)	0
O12	0.010 (4)	0.021 (5)	0.008 (4)	0	0.001 (3)	0
O13	0.020 (3)	0.005 (3)	0.009 (3)	0.002 (2)	0.003 (2)	0.002 (2)
P2	0.0074 (12)	0.0049 (13)	0.0076 (13)	0	0.0059 (10)	0
O21	0.002 (3)	0.010 (4)	0.006 (3)	0	0.000 (3)	0
O22	0.013 (4)	0.011 (4)	0.002 (3)	0	−0.001 (3)	0
O23	0.011 (3)	0.006 (3)	0.011 (3)	0.002 (2)	0.004 (2)	0.002 (2)
P3	0.0091 (13)	0.0039 (13)	0.0064 (13)	0	0.0023 (10)	0
O31	0.022 (4)	0.020 (5)	0.008 (4)	0	0.006 (3)	0
O32	0.022 (3)	0.020 (4)	0.007 (4)	0	0.006 (3)	0
O33	0.010 (3)	0.005 (3)	0.013 (3)	0.000 (2)	0.003 (2)	0.001 (2)

Geometric parameters (Å, º)

Bi1—O22	2.357 (7)	Fe2—O22	2.183 (8)
Bi1—O23^i	2.423 (6)	Fe2—Fe1^i	3.4175 (14)
Bi1—O23^ii	2.423 (6)	Fe2—Fe1^xi	3.4175 (14)
Bi1—O33^iii	2.442 (6)	Fe3—O11^xii	1.861 (8)
Bi1—O33	2.442 (6)	Fe3—O31^viii	1.915 (8)
Bi1—O13^iii	2.529 (6)	Fe3—O21	1.951 (7)
Bi1—O13	2.529 (6)	Fe3—O13^i	1.984 (6)
Bi1—Fe1^i	3.8243 (14)	Fe3—O13^ii	1.984 (6)
Fe1—O1^ii	1.981 (4)	Fe3—Bi1^ix	4.0093 (14)
Fe1—O1^iv	1.981 (4)	P1—O12	1.506 (8)
Fe1—O23^v	2.005 (5)	P1—O11	1.514 (8)
Fe1—O23	2.005 (5)	P1—O13	1.532 (6)
Fe1—O32	2.104 (5)	P1—O13^iii	1.532 (6)
Fe1—O32^v	2.104 (5)	P2—O22	1.520 (8)
Fe1—Fe1^vi	3.1540 (5)	P2—O23	1.531 (6)
Fe1—Fe1^vii	3.1540 (5)	P2—O23^iii	1.531 (6)
Fe2—O1	1.857 (8)	P2—O21	1.537 (8)
Fe2—O12^viii	1.932 (8)	P3—O31	1.475 (8)
Fe2—O33^ix	1.985 (6)	P3—O33	1.520 (6)
Fe2—O33^x	1.985 (6)	P3—O33^iii	1.520 (6)
Fe2—O21	2.154 (7)	P3—O32	1.568 (8)
O22—Bi1—O23^i	75.93 (17)	O12^viii—Fe2—O33^x	87.91 (16)
O22—Bi1—O23^ii	75.93 (17)	O33^ix—Fe2—O33^x	166.8 (3)
O23^i—Bi1—O23^ii	102.0 (3)	O1—Fe2—O21	158.8 (3)
O22—Bi1—O33^iii	78.6 (2)	O12^viii—Fe2—O21	85.8 (3)
O23^i—Bi1—O33^iii	145.39 (19)	O33^ix—Fe2—O21	83.62 (16)
O23^ii—Bi1—O33^iii	94.04 (19)	O33^x—Fe2—O21	83.62 (16)
O22—Bi1—O33	78.6 (2)	O1—Fe2—O22	92.9 (3)
O23^i—Bi1—O33	94.04 (19)	O12^viii—Fe2—O22	151.7 (3)
O23^ii—Bi1—O33	145.39 (19)	O33^ix—Fe2—O22	88.89 (16)
O33^iii—Bi1—O33	57.9 (3)	O33^x—Fe2—O22	88.89 (16)
O22—Bi1—O13^iii	150.09 (15)	O21—Fe2—O22	65.9 (3)
O23^i—Bi1—O13^iii	86.39 (18)	O11^xii—Fe3—O31^viii	108.5 (4)
O23^ii—Bi1—O13^iii	132.13 (19)	O11^xii—Fe3—O21	104.8 (3)
O33^iii—Bi1—O13^iii	105.20 (19)	O31^viii—Fe3—O21	146.8 (4)
O33—Bi1—O13^iii	78.77 (18)	O11^xii—Fe3—O13^i	95.46 (18)
O22—Bi1—O13	150.09 (15)	O31^viii—Fe3—O13^i	94.85 (17)
O23^i—Bi1—O13	132.13 (19)	O21—Fe3—O13^i	81.88 (17)
O23^ii—Bi1—O13	86.39 (18)	O11^xii—Fe3—O13^ii	95.46 (18)
O33^iii—Bi1—O13	78.77 (18)	O31^viii—Fe3—O13^ii	94.85 (16)
O33—Bi1—O13	105.20 (19)	O21—Fe3—O13^ii	81.88 (17)
O13^iii—Bi1—O13	56.3 (3)	O13^i—Fe3—O13^ii	162.3 (3)
O1^ii—Fe1—O1^iv	180.0	O12—P1—O11	109.4 (4)
O1^ii—Fe1—O23^v	89.8 (3)	O12—P1—O13	111.2 (3)
O1^iv—Fe1—O23^v	90.2 (3)	O11—P1—O13	111.3 (3)
O1^ii—Fe1—O23	90.2 (3)	O12—P1—O13^iii	111.2 (3)
O1^iv—Fe1—O23	89.8 (3)	O11—P1—O13^iii	111.3 (3)
O23^v—Fe1—O23	180.0	O13—P1—O13^iii	102.3 (4)
O1^ii—Fe1—O32	103.3 (2)	O22—P2—O23	113.0 (3)
O1^iv—Fe1—O32	76.7 (2)	O22—P2—O23^iii	113.0 (3)
O23^v—Fe1—O32	88.7 (3)	O23—P2—O23^iii	112.2 (4)
O23—Fe1—O32	91.3 (3)	O22—P2—O21	101.0 (4)
O1^ii—Fe1—O32^v	76.7 (2)	O23—P2—O21	108.4 (3)
O23^v—Fe1—O32^v	91.3 (3)	O23^iii—P2—O21	108.4 (3)
O23—Fe1—O32^v	88.7 (3)	O31—P3—O33	113.9 (3)
O32—Fe1—O32^v	180.0	O31—P3—O33^iii	113.9 (3)
O1—Fe2—O12^viii	115.4 (3)	O33—P3—O33^iii	102.1 (4)
O1—Fe2—O33^ix	96.54 (16)	O31—P3—O32	107.8 (5)
O12^viii—Fe2—O33^ix	87.91 (16)	O33—P3—O32	109.5 (3)
O1—Fe2—O33^x	96.54 (16)	O33^iii—P3—O32	109.5 (3)

Symmetry codes: (i) −x+1, y+1/2, −z; (ii) −x+1, −y, −z; (iii) x, −y+1/2, z; (iv) x−1, y, z; (v) −x, −y, −z; (vi) −x, y+1/2, −z; (vii) −x, y−1/2, −z; (viii) x, y, z−1; (ix) −x+1, −y+1, −z; (x) −x+1, y−1/2, −z; (xi) x+1, y, z; (xii) x−1, y, z−1.