Hexagonal ErMnO₃

The crystal structure of hexagonal ErMnO₃, erbium manganese trioxide, has been determined at room temperature. It is isomorphous with YMnO₃. Although we observed inversion twinning, similar to YMnO₃, the twin fractions do not have a 1:1 ratio, and the crystals are expected to show net ferroelectricity.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](Mn-O) = 0.005 Å
• R factor = 0.034
• wR factor = 0.079
• Data-to-parameter ratio = 23.0

checkCIF results

No syntax errors found


 Alert Level A:



PLAT_213  Alert A Atom  O1     has ADP max/min Ratio ...........       9.90

Author response: ... Both the Ueq and the refined anisotropic displacement patterns of O1 are in line with the values refined for the other atoms. Especially, if we take the standard deviations into account the differences between the a.d.p.'s is almos negligible. However using isotropic atomic displacement for all oxygen positions, yields a very similar model. All atomic positions stay equal within the error of the refinement.

 Alert Level B:



PLAT_111  Alert B ADDSYM detects (pseudo) centre of symmetry ...        100 Perc Fit

PLAT_111  Alert B ADDSYM detects (pseudo) centre of symmetry ...        100 Perc Fit


 Alert Level C:



DIFMN_02  Alert C The minimum difference density is < -0.1*ZMAX*0.75
          _refine_diff_density_min given =     -6.400
          Test value =     -5.100

DIFMN_03  Alert C The minimum difference density is < -0.1*ZMAX*0.75
          The relevant atom site should be identified.

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           38.49
         From the CIF: _reflns_number_total                759
         Count of symmetry unique reflns          411
         Completeness (_total/calc)            184.67%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       348
         Fraction of Friedel pairs measured     0.847
         Are heavy atom types Z>Si present          yes
          Please check that the estimate of the number of Friedel pairs is
          correct. If it is not, please give the correct count in the
          _publ_section_exptl_refinement section of the submitted CIF.


 1 Alert Level A = Potentially serious problem

 2 Alert Level B = Potential problem

 2 Alert Level C = Please check

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: XPREP (Bruker, 2000); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Farrugia, 2000); software used to prepare material for publication: PLATON (Spek, 2001).

Erbium Manganese Oxide

Crystal data

ErMnO3	Dx = 7.286 Mg m^−3
Mr = 270.20	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P63cm	Cell parameters from 3929 reflections
Hall symbol: P 6c -2	θ = 3.5–38.4°
a = 6.1121 (5) Å	µ = 38.68 mm^−1
c = 11.4200 (14) Å	T = 293 K
V = 369.47 (6) Å^3	Triangular platelet, black
Z = 6	0.11 × 0.10 × 0.08 mm
F(000) = 702

Data collection

Bruker SMART Apex diffractometer	759 independent reflections
Radiation source: fine focus sealed Siemens Mo tube	569 reflections with F > 4σ(F)
Parallel mounted graphite monochromator	Rint = 0.068
Detector resolution: 4096x4096 62x62(binned 512) pixels mm^-1	θmax = 38.5°, θmin = 3.6°
area detector scans	h = −6→10
Absorption correction: gaussian (XPREP, Bruker, 2000)	k = −10→8
Tmin = 0.019, Tmax = 0.083	l = −18→19
7178 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: none
R[F^2 > 2σ(F^2)] = 0.034	w = 1/[σ^2(Fo^2) + (0.0457P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.079	(Δ/σ)max < 0.001
S = 1.03	Δρmax = 3.8 (9) e Å^−3
759 reflections	Δρmin = −6.4 (9) e Å^−3
33 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.0223 (11)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
Er1	0.00000	0.00000	−0.22783 (9)	0.0084 (2)
Er2	0.33333	0.66667	0.22951 (2)	0.0089 (1)
Mn1	0.00000	0.3396 (3)	−0.00248 (17)	0.0090 (3)
O1	0.00000	0.3593 (12)	−0.1645 (7)	0.012 (2)
O2	0.00000	0.3113 (14)	0.1620 (7)	0.012 (2)
O3	0.00000	0.00000	−0.025 (3)	0.010 (3)
O4	0.33333	0.66667	0.0161 (13)	0.011 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Er1	0.0093 (3)	0.0093 (3)	0.0067 (3)	0.0047 (2)	0.0000	0.0000
Er2	0.0090 (2)	0.0090 (2)	0.0088 (2)	0.0045 (1)	0.0000	0.0000
Mn1	0.0122 (8)	0.0105 (5)	0.0048 (3)	0.0061 (4)	0.0000	0.0015 (4)
O1	0.030 (5)	0.008 (2)	0.004 (3)	0.015 (3)	0.0000	−0.001 (2)
O2	0.018 (5)	0.012 (3)	0.008 (3)	0.009 (2)	0.0000	0.001 (2)
O3	0.010 (4)	0.010 (4)	0.009 (7)	0.005 (2)	0.0000	0.0000
O4	0.013 (4)	0.013 (4)	0.008 (4)	0.0066 (19)	0.0000	0.0000

Geometric parameters (Å, º)

Er2—O4	2.437 (15)	Er1—O1^viii	2.312 (7)
Er2—O2	2.244 (7)	Er1—O2^ix	2.281 (7)
Er2—O1^i	2.306 (5)	Er1—O1^x	2.312 (7)
Er2—O2^ii	2.244 (9)	Er1—O2^xi	2.281 (8)
Er2—O1^iii	2.306 (5)	Er1—O3^vii	3.39 (3)
Er2—O2^iv	2.244 (5)	Mn1—O3	2.092 (4)
Er2—O4^v	3.273 (15)	Mn1—O4	2.030 (2)
Er2—O1^vi	2.306 (7)	Mn1—O1	1.854 (8)
Er1—O3	2.32 (3)	Mn1—O2	1.886 (8)
Er1—O1	2.312 (6)	Mn1—O4^xii	2.0296 (18)
Er1—O2^vii	2.281 (8)
O4—Er2—O2	69.9 (2)	O1^viii—Er1—O2^xi	164.8 (3)
O4—Er2—O1^i	121.66 (17)	O1^x—Er1—O2^ix	77.08 (19)
O4—Er2—O2^ii	69.9 (2)	O2^ix—Er1—O2^xi	92.5 (3)
O4—Er2—O1^iii	121.66 (18)	O1^x—Er1—O2^xi	77.1 (3)
O4—Er2—O2^iv	69.9 (2)	O3—Mn1—O4	119.49 (7)
O4—Er2—O1^vi	121.66 (19)	O3—Mn1—O1	86.7 (9)
O1^i—Er2—O2	168.4 (3)	O3—Mn1—O2	91.8 (10)
O2—Er2—O2^ii	108.8 (2)	O3—Mn1—O4^xii	119.49 (9)
O1^iii—Er2—O2	76.7 (2)	O4—Mn1—O1	94.2 (5)
O2—Er2—O2^iv	108.8 (2)	O4—Mn1—O2	86.6 (5)
O1^vi—Er2—O2	77.9 (3)	O4—Mn1—O4^xii	120.76 (13)
O1^i—Er2—O2^ii	77.9 (3)	O1—Mn1—O2	178.5 (3)
O1^i—Er2—O1^iii	95.0 (3)	O4^xii—Mn1—O1	94.2 (4)
O1^i—Er2—O2^iv	76.7 (2)	O4^xii—Mn1—O2	86.6 (4)
O1^i—Er2—O1^vi	95.0 (2)	Er1—O3—Mn1	97.1 (9)
O1^iii—Er2—O2^ii	168.4 (3)	Er1—O3—Mn1^viii	97.1 (9)
O2^ii—Er2—O2^iv	108.8 (3)	Er1—O3—Mn1^x	97.1 (9)
O1^vi—Er2—O2^ii	76.7 (3)	Mn1—O3—Mn1^viii	118.5 (4)
O1^iii—Er2—O2^iv	77.9 (3)	Mn1—O3—Mn1^x	118.5 (4)
O1^iii—Er2—O1^vi	95.0 (3)	Mn1^viii—O3—Mn1^x	118.5 (4)
O1^vi—Er2—O2^iv	168.4 (3)	Er2—O4—Mn1	96.0 (4)
O3—Er1—O1	71.8 (2)	Er2—O4—Mn1^iv	96.0 (4)
O3—Er1—O2^vii	123.5 (2)	Mn1—O4—Mn1^ii	118.92 (16)
O3—Er1—O1^viii	71.8 (2)	Mn1—O4—Mn1^iv	118.92 (16)
O3—Er1—O2^ix	123.47 (19)	Mn1^ii—O4—Mn1^iv	118.92 (16)
O3—Er1—O1^x	71.8 (2)	Er1—O1—Mn1	104.5 (3)
O3—Er1—O2^xi	123.5 (2)	Er2^vii—O1—Er1	101.0 (3)
O1—Er1—O2^vii	77.08 (18)	Er2^xiii—O1—Er1	101.0 (2)
O1—Er1—O1^viii	110.7 (2)	Er2^vii—O1—Mn1	123.2 (2)
O1—Er1—O2^ix	164.8 (3)	Er2^xiii—O1—Mn1	123.2 (3)
O1—Er1—O1^x	110.69 (16)	Er2^vii—O1—Er2^xiii	99.8 (3)
O1—Er1—O2^xi	77.1 (3)	Er2—O2—Mn1	107.2 (3)
O1^viii—Er1—O2^vii	77.1 (2)	Er2—O2—Er1^xiv	103.8 (3)
O2^vii—Er1—O2^ix	92.5 (2)	Er2—O2—Er2^xii	103.6 (3)
O1^x—Er1—O2^vii	164.8 (3)	Er1^xiv—O2—Mn1	128.7 (4)
O2^vii—Er1—O2^xi	92.5 (3)	Er2^xii—O2—Mn1	107.2 (2)
O1^viii—Er1—O2^ix	77.1 (3)	Er2^xii—O2—Er1^xiv	103.8 (3)
O1^viii—Er1—O1^x	110.7 (2)
O2—Er2—O4—Mn1	4.11 (14)	O3—Mn1—O4—Er2	−94.7 (11)
O4—Er2—O2—Mn1	−4.61 (16)	O1—Mn1—O4—Er2	176.74 (15)
O1—Er1—O3—Mn1	0.00 (14)	O2—Mn1—O4—Er2	−4.61 (16)
O3—Er1—O1—Mn1	0.00 (14)	O3—Mn1—O1—Er1	0.02 (15)
O4—Mn1—O3—Er1	−92.9 (7)	O4—Mn1—O1—Er1	119.35 (16)
O1—Mn1—O3—Er1	−0.02 (13)	O3—Mn1—O2—Er2	124.64 (18)
O2—Mn1—O3—Er1	−180.00 (18)	O4—Mn1—O2—Er2	5.21 (18)

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