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β-Al2TiO5 (dialuminium titanium penta­oxide), grown by rapid cooling of a melt of equimolar amounts of Al2O3 and TiO2, adopts the same overall structure as that crystallized by more conventional methods, such as sintering. Nevertheless, re­investigation of this structure has resulted in an improved structure model with previously unknown site preferences determined. Ti prefers the slightly more regular 4c octa­hedral site, leaving more room for Al at the 8f octa­hedral site. The formula has been determined as [4c][Al0.626 (7)Ti0.374 (7)][8f][Al0.687 (3)Ti0.313 (3)]2O5.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805021331/mg6041sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536805021331/mg6041Isup2.hkl
Contains datablock I

Key indicators

  • Single-crystal X-ray study
  • T = 297 K
  • Mean [sigma]() = 0.000 Å
  • Disorder in main residue
  • R factor = 0.028
  • wR factor = 0.028
  • Data-to-parameter ratio = 10.3

checkCIF/PLATON results

No syntax errors found



Alert level B PLAT301_ALERT_3_B Main Residue Disorder ......................... 26.00 Perc.
0 ALERT level A = In general: serious problem 1 ALERT level B = Potentially serious problem 0 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: RAPID-AUTO (Rigaku, 2003); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO (Rigaku 2003), and DIFDAT, SORTRF and ADDREF in Xtal3.7 (Hall et al., 2000); program(s) used to solve structure: atomic positions from Morosin & Lynch (1972); program(s) used to refine structure: CRYLSQ in Xtal3.7; molecular graphics: DIAMOND (Brandenburg, 2001), and FOURR, SLANT and CONTRS in Xtal3.7; software used to prepare material for publication: BONDLA, ATABLE and CIFIO in Xtal3.7.

(I) top
Crystal data top
Al2TiO5F(000) = 352
Mr = 181.84Dx = 3.675 Mg m3
Orthorhombic, CmcmMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2c 2Cell parameters from 8632 reflections
a = 3.605 (2) Åθ = 3.0–30.5°
b = 9.445 (4) ŵ = 3.02 mm1
c = 9.653 (4) ÅT = 297 K
V = 328.7 (3) Å3Block, blue
Z = 40.09 × 0.07 × 0.06 mm
Data collection top
Rigaku R-AXIS RAPID
diffractometer
304 independent reflections
Radiation source: normal-focus sealed tube288 reflections with F > 2σ(F)
Graphite monochromatorRint = 0.025
ω scansθmax = 30.5°, θmin = 4.2°
Absorption correction: gaussian
(RAPID-AUTO; Rigaku, 2003)
h = 55
Tmin = 0.827, Tmax = 0.880k = 1313
1774 measured reflectionsl = 1313
Refinement top
Refinement on F0 restraints
Least-squares matrix: full21 constraints
R[F2 > 2σ(F2)] = 0.028 w = 1/[σ2(F) + 0.015(F)]
wR(F2) = 0.028(Δ/σ)max = 0.00019
S = 1.09Δρmax = 0.91 e Å3
288 reflectionsΔρmin = 0.73 e Å3
28 parameters
Special details top

Refinement. The following constraints were used during refinement:

H-atom parameters constrained x(Al1)=0.0 + 1.0*x(Ti1) H-atom parameters constrained y(Al1)=0.0 + 1.0*y(Ti1) H-atom parameters constrained z(Al1)=0.0 + 1.0*z(Ti1) H-atom parameters constrained u11(Al1)=0.0 + 1.0*u11(Ti1) H-atom parameters constrained u22(Al1)=0.0 + 1.0*u22(Ti1) H-atom parameters constrained u33(Al1)=0.0 + 1.0*u33(Ti1) H-atom parameters constrained u12(Al1)=0.0 + 1.0*u12(Ti1) H-atom parameters constrained u13(Al1)=0.0 + 1.0*u13(Ti1) H-atom parameters constrained u23(Al1)=0.0 + 1.0*u23(Ti1) H-atom parameters constrained pop(Al1)=1.0–1.0*pop(Ti1)

H-atom parameters constrained pop(Ti2)=0.5–0.5*pop(Ti1) H-atom parameters constrained pop(Al2)=0.5 + 0.5*pop(Ti1)

H-atom parameters constrained x(Al2)=0.0 + 1.0*x(Ti2) H-atom parameters constrained y(Al2)=0.0 + 1.0*y(Ti2) H-atom parameters constrained z(Al2)=0.0 + 1.0*z(Ti2) H-atom parameters constrained u11(Al2)=0.0 + 1.0*u11(Ti2) H-atom parameters constrained u22(Al2)=0.0 + 1.0*u22(Ti2) H-atom parameters constrained u33(Al2)=0.0 + 1.0*u33(Ti2) H-atom parameters constrained u12(Al2)=0.0 + 1.0*u12(Ti2) H-atom parameters constrained u13(Al2)=0.0 + 1.0*u13(Ti2) H-atom parameters constrained u23(Al2)=0.0 + 1.0*u23(Ti2)

i.e., basically placing Ti and Al together at same site as Al3+ and Ti4+ have similar ionic radii, so no hope of distinguish them from each other during refinement. And the residual electron density does not contradict this approach···

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Ti100.18547 (10)0.250000.0073 (4)0.374 (7)
Al100.18547 (10)0.250000.0073 (4)0.626 (7)
Ti200.13551 (7)0.56186 (7)0.0089 (3)0.313 (3)
Al200.13551 (7)0.56186 (7)0.0089 (3)0.687 (3)
O100.7572 (3)0.250000.0084 (12)
O200.0485 (2)0.1165 (2)0.0089 (9)
O300.3125 (2)0.0724 (2)0.0091 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ti10.0064 (5)0.0088 (5)0.0069 (4)000
Al10.0064 (5)0.0088 (5)0.0069 (4)000
Ti20.0062 (3)0.0102 (4)0.0102 (3)000.0001 (2)
Al20.0062 (3)0.0102 (4)0.0102 (3)000.0001 (2)
O10.0069 (12)0.0101 (12)0.0082 (12)000
O20.0120 (10)0.0068 (8)0.0080 (9)000.0013 (7)
O30.0059 (8)0.0082 (8)0.0134 (10)000.0020 (7)
Geometric parameters (Å, º) top
Ti1—O21.826 (2)Ti2—O2ii1.816 (2)
Ti1—O2i1.826 (2)Ti2—O3iii1.8708 (11)
Ti1—O11.9253 (14)Ti2—O31.8708 (11)
Ti1—O11.9253 (14)Ti2—O2i1.907 (2)
Ti1—O32.093 (2)Ti2—O12.0799 (17)
Ti1—O3i2.093 (2)Ti2—O3i2.115 (2)
Al1—O21.826 (2)Al2—O2ii1.816 (2)
Al1—O2i1.826 (2)Al2—O3iii1.8708 (11)
Al1—O11.9253 (14)Al2—O31.8708 (11)
Al1—O11.9253 (14)Al2—O2i1.907 (2)
Al1—O32.093 (2)Al2—O12.0799 (17)
Al1—O3i2.093 (2)Al2—O3i2.115 (2)
O2—Ti1—O380.09 (9)O2ii—Ti2—O1102.30 (10)
O2—Ti1—O2i89.80 (10)O2ii—Ti2—O2i81.35 (9)
O2—Ti1—O3i169.89 (9)O2ii—Ti2—O3i159.08 (9)
O2—Ti1—O1104.42 (6)O2ii—Ti2—O3103.61 (6)
O2—Ti1—O1104.42 (6)O2ii—Ti2—O3iii103.61 (6)
O3—Ti1—O2i169.89 (9)O1—Ti2—O2i176.35 (10)
O3—Ti1—O3i110.03 (9)O1—Ti2—O3i98.62 (10)
O3—Ti1—O178.37 (5)O1—Ti2—O379.90 (6)
O3—Ti1—O178.37 (5)O1—Ti2—O3iii79.90 (6)
O2i—Ti1—O3i80.09 (9)O2i—Ti2—O3i77.73 (9)
O2i—Ti1—O1104.42 (6)O2i—Ti2—O399.33 (7)
O2i—Ti1—O1104.42 (6)O2i—Ti2—O3iii99.33 (7)
O3i—Ti1—O178.37 (5)O3i—Ti2—O379.98 (6)
O3i—Ti1—O178.37 (5)O3i—Ti2—O3iii79.98 (6)
O1—Ti1—O1138.82 (13)O3—Ti2—O3iii148.91 (9)
O2—Al1—O380.09 (9)O2ii—Al2—O1102.30 (10)
O2—Al1—O2i89.80 (10)O2ii—Al2—O2i81.35 (9)
O2—Al1—O3i169.89 (9)O2ii—Al2—O3i159.08 (9)
O2—Al1—O1104.42 (6)O2ii—Al2—O3103.61 (6)
O2—Al1—O1104.42 (6)O2ii—Al2—O3iii103.61 (6)
O3—Al1—O2i169.89 (9)O1—Al2—O2i176.35 (10)
O3—Al1—O3i110.03 (9)O1—Al2—O3i98.62 (10)
O3—Al1—O178.37 (5)O1—Al2—O379.90 (6)
O3—Al1—O178.37 (5)O1—Al2—O3iii79.90 (6)
O2i—Al1—O3i80.09 (9)O2i—Al2—O3i77.73 (9)
O2i—Al1—O1104.42 (6)O2i—Al2—O399.33 (7)
O2i—Al1—O1104.42 (6)O2i—Al2—O3iii99.33 (7)
O3i—Al1—O178.37 (5)O3i—Al2—O379.98 (6)
O3i—Al1—O178.37 (5)O3i—Al2—O3iii79.98 (6)
O1—Al1—O1138.82 (13)O3—Al2—O3iii148.91 (9)
Symmetry codes: (i) x, y, z+1/2; (ii) x, y, z+1/2; (iii) x+1/2, y+1/2, z+1/2.
Comparison of M—O bond lengths (Å) as determined in this report with those determined by Morosin &amp; Lynch (1972) top
This reportPrevious report
M1—O2i1.826 (2) × 21.823 (4) × 2
M1—O1ii, iii1.9253 (14) × 21.920 (2) × 2
M1—O3i2.093 (2) × 22.087 (4) × 2
M2—O2iv1.816 (2)1.814 (4)
M2—O3v, vi1.8708 (11) × 21.864 (1) × 2
M2—O2i1.907 (2)1.900 (4)
M2—O1vii2.0799 (17)2.076 (3)
M2—O3i2.115 (2)2.114 (4)
[Symmetry codes: (i) -x, y, 1/2-z; (ii) x-1/2, y-1/2, z; (iii) 1/2+x, y-1/2, z; (iv) -x, -y, 1/2+z; (v) 1/2-x, 1/2-y, 1/2+z; (vi) -1/2-x, 1/2-y, 1/2+z; (vii) -x, 1-y, 1/2+z.
 

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