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Structure factors for small hydrothermally grown orthorhombic neodymium and dysprosium iron oxides RFeO3 (R = Nd, Dy) were measured with focused λ = 0.84 Å synchrotron radiation using a fast avalanche photodiode (APD) counter. Higher symmetry in the deformation electron density (Δρ) maps reflects the coordination of the magnetic atoms in the structure and implies that Δρ is sensitive to the cation–cation magnetic interactions. Within a given compound the local Δρ topographies around the R and Fe atoms are similar, but differ markedly between compounds. The difference in Δρ near the Nd and Dy atoms is associated with the different type of spin reorientation transitions in these compounds. The R–Fe magnetic interactions determine the magnetic phase transitions and consequently affect the electron distribution. Synchrotron radiation diffraction imaging of the electron density provides an additional tool for probing the magnetic properties of materials.
Supporting information
 | Crystallographic Information File (CIF) |
 | Structure factor file (CIF format) |
| Structure factor file (CIF format) |
Computing details top
For both compounds, data reduction: Xtal DIFDAT ADDREF SORTRF ABSORB; program(s) used to solve structure: Xtal; program(s) used to refine structure: Xtal CRYLSQ; molecular graphics: Xtal; software used to prepare material for publication: Xtal CIFIO.
![[Figure 1]](http://journals.iucr.org/b/issues/1999/01/00/sh0113/sh0113fig1thm.gif)
![[Figure 2]](http://journals.iucr.org/b/issues/1999/01/00/sh0113/sh0113fig2thm.gif)
(ndfeo3) top
Crystal data top
| NdFeO3 | F(000) = 440 |
| Mr = 248.08 | Dx = 6.971 Mg m−3 |
| Orthorhombic, Pnma | Xray vertical wiggler radiation, λ = 0.84 Å |
| Hall symbol: -P 2ac 2n | Cell parameters from 12 reflections |
| a = 5.5887 (5) Å | θ = 40.8–49.4° |
| b = 7.7619 (5) Å | µ = 41.64 mm−1 |
| c = 5.4489 (5) Å | T = 293 K |
| V = 236.37 (3) Å3 | Rectangular, red |
| Z = 4 | 0.25x10-5 × × mm |
Data collection top
| Bl14a 4-circle diffractometer | 1328 reflections with I > 2σ(I) |
| Radiation source: photon factory bl14a | Rint = 0.059 |
| Si(111) monochromator | θmax = 66.8°, θmin = 5.4° |
| ω–2θ scans | h = −12→12 |
| Absorption correction: analytical ? | k = −16→16 |
| Tmin = 0.586, Tmax = 0.679 | l = −11→11 |
| 9496 measured reflections | 6 standard reflections every 94 reflections |
| 1328 independent reflections | intensity decay: 3% |
Refinement top
| Refinement on F | 0 constraints |
| Least-squares matrix: full | w = 1/σ2(F) |
| R[F2 > 2σ(F2)] = 0.029 | (Δ/σ)max = 0.00009 |
| wR(F2) = 0.033 | Δρmax = 5.00 e Å−3 |
| S = 2.49 | Δρmin = −7.82 e Å−3 |
| 1328 reflections | Extinction correction: Larson (1970) |
| 28 parameters | Extinction coefficient: r*<σ (r*) |
| 0 restraints |
Crystal data top
| NdFeO3 | V = 236.37 (3) Å3 |
| Mr = 248.08 | Z = 4 |
| Orthorhombic, Pnma | Xray vertical wiggler radiation, λ = 0.84 Å |
| a = 5.5887 (5) Å | µ = 41.64 mm−1 |
| b = 7.7619 (5) Å | T = 293 K |
| c = 5.4489 (5) Å | 0.25x10-5 × × mm |
Data collection top
| Bl14a 4-circle diffractometer | 1328 reflections with I > 2σ(I) |
| Absorption correction: analytical ? | Rint = 0.059 |
| Tmin = 0.586, Tmax = 0.679 | 6 standard reflections every 94 reflections |
| 9496 measured reflections | intensity decay: 3% |
| 1328 independent reflections |
Refinement top
| R[F2 > 2σ(F2)] = 0.029 | 28 parameters |
| wR(F2) = 0.033 | 0 restraints |
| S = 2.49 | Δρmax = 5.00 e Å−3 |
| 1328 reflections | Δρmin = −7.82 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
| x | y | z | Uiso*/Ueq | ||
| Nd | 0.04907 (3) | 0.25000 | −0.01088 (3) | 0.00581 (4) | |
| Fe | 0.00000 | 0.00000 | 0.50000 | 0.00473 (12) | |
| O1 | 0.4760 (4) | 0.25000 | 0.0866 (4) | 0.0068 (7) | |
| O2 | −0.2949 (3) | −0.0459 (2) | 0.2955 (3) | 0.0067 (5) |
Atomic displacement parameters (Å2) top
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Nd | 0.00706 (5) | 0.00374 (4) | 0.00665 (4) | 0.00000 | −0.00076 (3) | 0.00000 |
| Fe | 0.00616 (12) | 0.00288 (11) | 0.00515 (12) | 0.00028 (9) | 0.00012 (8) | −0.00008 (8) |
| O1 | 0.0099 (7) | 0.0021 (6) | 0.0083 (7) | 0.00000 | −0.0011 (5) | 0.00000 |
| O2 | 0.0075 (5) | 0.0055 (5) | 0.0073 (4) | −0.0011 (4) | −0.0022 (4) | 0.0008 (3) |
(dyfeo3) top
Crystal data top
| DyFeO3 | F(000) = 464 |
| Mr = 266.35 | Dx = 7.818 Mg m−3 |
| Orthorhombic, Pnma | Xray vertical wiggler radiation, λ = 0.84 Å |
| Hall symbol: -P 2ac 2n | Cell parameters from 12 reflections |
| a = 5.5957 (8) Å | θ = 42.1–49.4° |
| b = 7.6290 (9) Å | µ = 58.69 mm−1 |
| c = 5.3009 (11) Å | T = 293 K |
| V = 226.29 (6) Å3 | Rectangular, red |
| Z = 4 | 0.18x10-5 × × mm |
Data collection top
| Bl14a 4-circle diffractometer | 1141 reflections with I > 2σ(I) |
| Radiation source: photon factory bl14a | Rint = 0.054 |
| Si(111) monochromator | θmax = 67.5°, θmin = 5.5° |
| ω–2θ scans | h = −12→12 |
| Absorption correction: analytical ? | k = −16→16 |
| Tmin = 0.513, Tmax = 0.587 | l = −11→4 |
| 4384 measured reflections | 6 standard reflections every 94 reflections |
| 1141 independent reflections | intensity decay: 4% |
Refinement top
| Refinement on F | 0 constraints |
| Least-squares matrix: full | w = 1/σ2(F) |
| R[F2 > 2σ(F2)] = 0.038 | (Δ/σ)max = 0.00009 |
| wR(F2) = 0.04 | Δρmax = 8.07 e Å−3 |
| S = 3.26 | Δρmin = −4.60 e Å−3 |
| 1141 reflections | Extinction correction: Larson (1970) |
| 28 parameters | Extinction coefficient: r*<σ (r*) |
| 0 restraints |
Crystal data top
| DyFeO3 | V = 226.29 (6) Å3 |
| Mr = 266.35 | Z = 4 |
| Orthorhombic, Pnma | Xray vertical wiggler radiation, λ = 0.84 Å |
| a = 5.5957 (8) Å | µ = 58.69 mm−1 |
| b = 7.6290 (9) Å | T = 293 K |
| c = 5.3009 (11) Å | 0.18x10-5 × × mm |
Data collection top
| Bl14a 4-circle diffractometer | 1141 reflections with I > 2σ(I) |
| Absorption correction: analytical ? | Rint = 0.054 |
| Tmin = 0.513, Tmax = 0.587 | 6 standard reflections every 94 reflections |
| 4384 measured reflections | intensity decay: 4% |
| 1141 independent reflections |
Refinement top
| R[F2 > 2σ(F2)] = 0.038 | 28 parameters |
| wR(F2) = 0.04 | 0 restraints |
| S = 3.26 | Δρmax = 8.07 e Å−3 |
| 1141 reflections | Δρmin = −4.60 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
| x | y | z | Uiso*/Ueq | ||
| Dy | 0.06665 (5) | 0.25000 | −0.01725 (5) | 0.00783 (9) | |
| Fe | 0.00000 | 0.00000 | 0.50000 | 0.0071 (2) | |
| O1 | 0.4626 (9) | 0.25000 | 0.1081 (10) | 0.0094 (15) | |
| O2 | −0.3033 (6) | −0.0557 (4) | 0.3075 (6) | 0.0090 (10) |
Atomic displacement parameters (Å2) top
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Dy | 0.00683 (8) | 0.00767 (8) | 0.00899 (10) | 0.00000 | −0.00055 (7) | 0.00000 |
| Fe | 0.0074 (2) | 0.0060 (2) | 0.0080 (3) | 0.00050 (17) | 0.0004 (2) | −0.0000 (2) |
| O1 | 0.0106 (15) | 0.0044 (11) | 0.0133 (18) | 0.00000 | −0.0029 (13) | 0.00000 |
| O2 | 0.0085 (10) | 0.0091 (9) | 0.0092 (11) | −0.0012 (8) | −0.0015 (8) | 0.0009 (8) |
Experimental details
| (ndfeo3) | (dyfeo3) | |
| Crystal data | ||
| Chemical formula | NdFeO3 | DyFeO3 |
| Mr | 248.08 | 266.35 |
| Crystal system, space group | Orthorhombic, Pnma | Orthorhombic, Pnma |
| Temperature (K) | 293 | 293 |
| a, b, c (Å) | 5.5887 (5), 7.7619 (5), 5.4489 (5) | 5.5957 (8), 7.6290 (9), 5.3009 (11) |
| V (Å3) | 236.37 (3) | 226.29 (6) |
| Z | 4 | 4 |
| Radiation type | Xray vertical wiggler, λ = 0.84 Å | Xray vertical wiggler, λ = 0.84 Å |
| µ (mm−1) | 41.64 | 58.69 |
| Crystal size (mm) | 0.25x10-5 × × | 0.18x10-5 × × |
| Data collection | ||
| Diffractometer | Bl14a 4-circle diffractometer | Bl14a 4-circle diffractometer |
| Absorption correction | Analytical | Analytical |
| Tmin, Tmax | 0.586, 0.679 | 0.513, 0.587 |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 9496, 1328, 1328 | 4384, 1141, 1141 |
| Rint | 0.059 | 0.054 |
| (sin θ/λ)max (Å−1) | 1.094 | 1.100 |
| Refinement | ||
| R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.033, 2.49 | 0.038, 0.04, 3.26 |
| No. of reflections | 1328 | 1141 |
| No. of parameters | 28 | 28 |
| Δρmax, Δρmin (e Å−3) | 5.00, −7.82 | 8.07, −4.60 |
Computer programs: Xtal DIFDAT ADDREF SORTRF ABSORB, Xtal CRYLSQ, Xtal CIFIO.
Fractional coordinates and anisotropic vibration parameters (Uij,
2) with s.u.'s in parentheses for NdFeO3 and DyFeO3 top
| T = exp[-2π2 (U11(ha*)2 + ··· + 2U12ha*kb* + ···)]. Parameters for DyFeO3 follow those for NdFeO3 for each table entry. |
| x | y | z | U11 | U22 | U33 | U12 | U13 | U23 | |
| Nd | .04907 (3) | 0.25 | -.01088 (3) | .00706 (5) | .00374 (4) | .00665 (4) | 0 | -.00076 (3) | 0 |
| Dy | .06665 (5) | 0.25 | -.01725 (5) | .00683 (8) | .00767 (8) | .0090 (1) | 0 | -.00055 (7) | 0 |
| Fe | 0 | 0 | 0.5 | .0062 (1) | .0029 (1) | .0052 (1) | .00028 (9) | .00012 (8) | -.00008 (8) |
| Fe | 0 | 0 | 0.5 | .0074 (2) | .0060 (2) | .0080 (3) | .0005 (2) | .0004 (2) | -.0000 (2) |
| O1 | .4760 (4) | 1/4 | .0866 (4) | .0099 (7) | .0021 (6) | .0083 (7) | 0 | -.0011 (5) | 0 |
| .4626 (9) | 1/4 | .1081 (10) | .011 (2) | .004 (1) | .013 (2) | 0 | -.003 (1) | 0 | |
| O2 | -.2949 (3) | -.0459 (2) | .2955 (3) | .0075 (5) | .0055 (5) | .0073 (4) | -.0011 (4) | -.0022 (4) | .0008 (3) |
| -.3033 (6) | -.0557 (4) | .3075 (6) | .009 (1) | .0091 (9) | .0092 (11) | -.0012 (8) | -.0015 (8) | .0009 (8) |
Table 3. Selected interatomic distances and angles (Å,°)
for RFeO3 (R=Nd & Dy). top
| Results for DyFeO3 follow those for NdFeO3 for each table entry. |
| R—Ri (2) | 3.8209 (9) | Fe—Feviii (2) | 3.8810 (3) |
| 3.7305 (6) | 3.8145 (4) | ||
| R—Rii (2) | 3.9213 (2) | Fe—Fevii (4) | 3.9027 (3) |
| 3.8910 (4) | 3.8539 (5) | ||
| R—Riii (2) | 3.9863 (3) | Fe—O1v (4) | 2.0015 (6) |
| 3.9819 (6) | 2.002 (1) | ||
| R—Feiii (2) | 3.1812 (2) | Fe—O2ix (2) | 2.008 (2) |
| 3.0864 (4) | 2.012 (3) | ||
| R—Feiv (2) | 3.3081 (2) | Fe—O2 | 2.021 (2) |
| 3.2133 (5) | 2.026 (3) | ||
| R—Fe (2) | 3.4044 (3) | O1—O1v (2) | 3.314 (3) |
| 3.3608 (5) | 3.177 (7) | ||
| R—Fev (2) | 3.6312 (3) | O1—O2ii (2) | a2.805 (3) |
| 3.7013 (5) | a2.801 (6) | ||
| R—O1v | 2.348 (2) | O1—O2iii (2) | a2.824 (2) |
| 2.246 (5) | a2.802 (4) | ||
| R—O1 | 2.444 (2) | O1—O2x (2) | a2.864 (3) |
| 2.313 (4) | a2.876 (4) | ||
| R—O1i | 3.163 (2) | O1—O2xi (2) | a2.865 (2) |
| 3.186 (5) | a2.893 (5) | ||
| R—O1vi | 3.247 (2) | O1—O2xii (2) | 3.856 (3) |
| 3.445 (5) | 3.548 (6) | ||
| R—O2vii (2) | 2.375 (2) | O2—O2xiii (2) | a2.838 (2) |
| 2.287 (3) | a2.863 (5) | ||
| R—O2ii (2) | 2.608 (2) | O2—O2vii (2) | a2.860 (2) |
| 2.514 (3) | a2.847 (5) | ||
| R—O2iii (2) | 2.723 (2) | O2—O2xiv | 3.169 (2) |
| 2.684 (3) | 2.965 (5) | ||
| R—O2 (2) | 3.429 (2) | O2—O2xv | 3.276 (2) |
| 3.562 (3) | 3.120 (5) | ||
| Iron octahedra angles | |||
| O1v—Fe—O2 | 89.20 (8) | O1v—Fe–O1xvi | 180 by |
| 88.2 (2) | symmetry | ||
| O1v—Fe—O2ix | 88.79 (8) | O2xiii—Fe—O2ix | 180 by |
| 88.5 (2) | symmetry | ||
| O2xiii—Fe—O2xii | 90.45 (7) | Feiii—O1—Fexi | 151.6 (1) |
| 89.7 (1) | 144.5 (3) | ||
| Fe—O2—Fevii | 151.20 (9) | ||
| 145.3 (2) |
| Symmetry codes:
(i) x-1/2,1/2-y,-1/2-z;
(ii) -x,1/2+y,z;
(iii) 1/2+x,1/2-y,1/2-z;
(iv) x,y,z-1;
(v) x-1/2,1/2-y,1/2-z;
(vi) x-1,y,z;
(vii) -1/2-x,-y,z-1/2;
(viii) -x,1/2+y,1-z;
(ix) -1/2-x,-y,1/2+z;
(x) 1+x,y,z;
(xi) 1/2-x,-y,z-1/2;
(xii) -x,-y,1-z;
(xiii) 1/2+x,y,1/2-z;
(xiv) x,-1/2-y,z;
(xv) -1-x,-y,1-z;
(xvi) 1/2-x,-y,1/2+z. a O distances in the FeO6 octahedra. |
Table 4. Atomic charges in electrons from the Hirshfeld
partitioning of Δ\ for RFeO3 (R=Nd and Dy) top
| NdFeO3 | DyFeO3 | |
| R | 1.0 (1) | 1.19 (8) |
| Fe | 1.3 (1) | 0.61 (8) |
| O1 | -0.76 (8) | -0.60 (6) |
| O2 | -0.78 (8) | -0.60 (6) |
