Structure and stability of BaTiSi2O7

Viani, A.; Palermo, A.; Zanardi, S.; Demitri, N.; Petrícek, V.; Varini, F.; Belluso, E.; Ståhl, K.; Gualtieri, A.F.

doi:10.1107/S2052520615002942

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Structure and stability of BaTiSi₂O₇

A. Viani, A. Palermo, S. Zanardi, N. Demitri, V. Petrícek, F. Varini, E. Belluso, K. Ståhl and A. F. Gualtieri

Due to their optical, photo-luminescence (PL), and afterglow properties, barium titanosilicates are compounds of great interest for functional materials and light-emitting devices. Among them, BaTiSi₂O₇ (BTS2) is certainly one of the most intriguing; it displays peculiar properties (e.g. PL orange emission) whose exhaustive explanation has been hampered to date by the lack of a structure model. In this work, BTS2 and the related compound BaTiSi₄O₁₁ (BTS4) were synthesized through conventional solid-state reaction methods. BTS2 invariably shows complex twinning patterns. Thus, its structure solution and Rietveld structure refinement were attempted using synchrotron powder diffraction. BTS2 was found to be an intergrowth of monoclinic and triclinic crystals. The monoclinic phase has the space group P2₁/n and unit cell a = 7.9836 (3), b = 10.0084 (4), c = 7.4795 (3) Å, and β = 100.321 (3)°, whereas the triclinic phase has the space group $P\bar 1$ and unit cell a = 7.99385 (4), b = 10.01017 (5), c = 7.47514 (3) Å, α = 90.084 (8), β = 100.368 (8) and γ = 89.937 (9)°. These lattices can be seen as a distortion of that of tetragonal synthetic β-BaVSi₂O₇ with Ti in place of V. The structure models obtained from this study confirm the presence of fivefold coordinated Ti atoms in a distorted pyramidal configuration. The proposed solution supports existing theories for the explanation of the PL orange colour in BTS2.

Keywords: photo-luminescence; optical properties; solid-state reactions.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S2052520615002942/po5015sup1.cif Contains datablocks BTS2_Monoclinic_publ, BTS2_EL__overall, BTS2_Monoclinic, BTS2_Monoclinic_p_03, BATISI2O7D_publ, BATISI2O7D_overall, BATISI2O7D_Triclinic, BATISI2O7D
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2052520615002942/po5015BTS2dataset1sup2.rtv Data set 1 from Elettra (monoclinic form)
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2052520615002942/po5015BTS2dataset2sup3.rtv Data set 2 from Elettra (monoclinic form)
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2052520615002942/po5015BTS2dataset3sup4.rtv Data set 3 from Elettra (monoclinic form)
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2052520615002942/po5015BTS2dataset4sup5.rtv Data set 4 from Elettra (monoclinic form)
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2052520615002942/po5015BTS2dataset5sup6.rtv Data set 5 from Elettra (monoclinic form)
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2052520615002942/po5015BTS2dataset6sup7.rtv Data set 6 from Elettra (monoclinic form)
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S2052520615002942/po5015BATISI2O7D_Triclinicsup8.rtv Data set from ESRF (triclinic form)

CCDC references: 1048900; 1048901

Experimental top

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 1.

Results and discussion top

Computing details top

Figures top

(BTS2_Monoclinic) top

Crystal data top

BaO_6.84Si₂Ti	β = 100.321 (3)°
M_r = 350.88	V = 587.97 (5) Å³
Monoclinic, P2₁/n	Z = 4
Hall symbol: -P 2yn	D_x = 4 Mg m⁻³
a = 7.9836 (3) Å	Synchrotron radiation, λ = 0.70448 Å
b = 10.0084 (4) Å	T = 295 K
c = 7.4795 (3) Å	?, ? × ? × ? mm

Data collection top

Radiation source: synchrotron

2θ_min = 0.011°, 2θ_max = 65.412°, 2θ_step = 0.044°

Refinement top

Least-squares matrix: full	1474 data points
R_p = 0.042	Profile function: CW Profile function number 2 with 18 terms Profile coefficients for Simpson's rule integration of pseudovoigt function C.J. Howard (1982). J. Appl. Cryst.,15,615-620. P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Peak tails are ignored where the intensity is below 0.0050 times the peak
R_wp = 0.054	179 parameters
R_exp = 0.006	8 restraints
R(F²) = 0.09784	(Δ/σ)_max = 0.04
χ² = 130.188	Background function: GSAS Background function number 1 with 24 terms. Shifted Chebyshev function of 1st kind

Crystal data top

BaO_6.84Si₂Ti	β = 100.321 (3)°
M_r = 350.88	V = 587.97 (5) Å³
Monoclinic, P2₁/n	Z = 4
a = 7.9836 (3) Å	Synchrotron radiation, λ = 0.70448 Å
b = 10.0084 (4) Å	T = 295 K
c = 7.4795 (3) Å	?, ? × ? × ? mm

Data collection top

2θ_min = 0.011°, 2θ_max = 65.412°, 2θ_step = 0.044°

Refinement top

R_p = 0.042	χ² = 130.188
R_wp = 0.054	1474 data points
R_exp = 0.006	179 parameters
R(F²) = 0.09784	8 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ba	0.0043 (4)	0.26379 (14)	0.4945 (5)	0.015 (5)*
Ti	0.6409 (4)	0.0039 (10)	0.3516 (4)	0.004 (5)*
Si1	0.2972 (7)	0.5189 (8)	0.2522 (9)	0.012 (1)*
Si2	0.4759 (8)	0.2726 (6)	0.4813 (11)	0.004 (1)*
O1	0.627 (2)	0.214 (3)	0.392 (3)	0.031 (5)*	0.843 (16)
O2	0.6027 (18)	−0.1927 (16)	0.374 (2)	0.005 (1)*
O3	0.390 (2)	0.3781 (14)	0.335 (2)	0.004 (1)*
O4	0.7128 (13)	0.002 (3)	0.1594 (13)	0.004 (2)*
O5	0.371 (2)	0.6453 (15)	0.375 (2)	0.013 (2)*
O6	0.3325 (12)	0.4778 (17)	0.0482 (14)	0.018 (1)*
O7	0.1007 (13)	0.4691 (14)	0.2287 (17)	0.024 (2)*

Geometric parameters (Å, º) top

Ba—Baⁱ	5.282 (3)	O1—Si2	1.591 (15)
Ba—Baⁱⁱ	4.730 (3)	O1—O2^xvii	3.324 (12)
Ba—Baⁱⁱⁱ	4.965 (3)	O1—O2^ix	2.757 (12)
Ba—Ba^iv	5.945 (5)	O1—O3	2.49 (2)
Ba—Ba^v	5.945 (5)	O1—O3^vi	3.70 (3)
Ba—Ba^vi	4.965 (3)	O1—O4	2.91 (3)
Ba—Ti^vii	3.901 (8)	O1—O4^xvii	3.20 (4)
Ba—Ti^viii	3.570 (8)	O1—O5^xiii	2.239 (19)
Ba—Ti^ix	3.919 (8)	O1—O6^vi	2.66 (3)
Ba—Tiⁱⁱⁱ	5.621 (6)	O1—O7^x	3.09 (2)
Ba—Ti^iv	3.562 (8)	O1—O7^vi	3.15 (3)
Ba—Si1	4.098 (7)	O2—Ba^x	2.773 (18)
Ba—Si1^x	3.602 (7)	O2—Ba^xii	4.964 (16)
Ba—Si1ⁱⁱ	3.968 (8)	O2—Ba^ix	3.195 (15)
Ba—Si1^iv	3.949 (8)	O2—Ti	2.002 (19)
Ba—Si2^vii	4.203 (7)	O2—Ti^xvi	4.185 (19)
Ba—Si2	3.785 (7)	O2—Ti^ix	3.603 (17)
Ba—Si2ⁱⁱⁱ	3.822 (9)	O2—Si1^xix	3.784 (17)
Ba—Si2^iv	3.706 (9)	O2—Si1^x	3.807 (17)
Ba—O1^vii	3.014 (18)	O2—Si1^vi	3.442 (19)
Ba—O1ⁱⁱⁱ	4.784 (19)	O2—Si2^ix	1.563 (14)
Ba—O1^iv	2.97 (2)	O2—O1^xvi	3.324 (12)
Ba—O2^viii	2.773 (18)	O2—O1^ix	2.757 (12)
Ba—O2^xi	4.964 (16)	O2—O3^ix	2.852 (18)
Ba—O2^ix	3.195 (15)	O2—O4	2.77 (3)
Ba—O3^vii	4.972 (16)	O2—O4^xvi	3.42 (3)
Ba—O3	3.677 (17)	O2—O5^xix	2.463 (19)
Ba—O3^x	4.736 (12)	O2—O6^vi	2.97 (2)
Ba—O3ⁱⁱ	5.080 (16)	O2—O7^x	2.33 (2)
Ba—O3ⁱⁱⁱ	5.059 (14)	O2—O7^vi	3.47 (2)
Ba—O3^iv	3.188 (17)	O3—Ba	3.677 (17)
Ba—O4^vii	4.06 (2)	O3—Ba^xv	4.972 (16)
Ba—O4^viii	3.05 (3)	O3—Ba^viii	4.736 (12)
Ba—O4^ix	4.10 (2)	O3—Baⁱⁱ	5.080 (16)
Ba—O4^iv	3.01 (3)	O3—Ba^v	3.188 (17)
Ba—O5	4.988 (15)	O3—Ba^vi	5.059 (14)
Ba—O5^x	3.319 (17)	O3—Ti	4.240 (17)
Ba—O5^xii	4.793 (14)	O3—Ti^viii	4.399 (16)
Ba—O5ⁱⁱ	3.434 (17)	O3—Tiⁱⁱⁱ	3.977 (14)
Ba—O5^xiii	4.994 (16)	O3—Si1	1.658 (13)
Ba—O6	5.073 (10)	O3—Si1^x	3.901 (16)
Ba—O6^xiv	4.971 (14)	O3—Si1^xiii	3.754 (17)
Ba—O6^x	3.185 (16)	O3—Si2	1.588 (12)
Ba—O6^iv	2.844 (15)	O3—Si2^xiii	3.839 (18)
Ba—O7	3.052 (13)	O3—Si2ⁱⁱⁱ	4.128 (17)
Ba—O7^x	4.829 (12)	O3—O1	2.49 (2)
Ba—O7ⁱⁱ	3.571 (13)	O3—O1ⁱⁱⁱ	3.70 (3)
Ba—O7^iv	4.572 (11)	O3—O2^ix	2.852 (18)
Ti—Ba^xv	3.901 (8)	O3—O3^xiii	3.69 (3)
Ti—Ba^x	3.570 (8)	O3—O4^xvii	3.40 (2)
Ti—Ba^ix	3.919 (8)	O3—O4^iv	3.25 (2)
Ti—Ba^v	3.562 (8)	O3—O5	2.699 (12)
Ti—Ba^vi	5.621 (6)	O3—O5^x	3.320 (11)
Ti—Ti^ix	3.433 (6)	O3—O5^xiii	2.638 (13)
Ti—Si1^x	3.448 (6)	O3—O6	2.333 (16)
Ti—Si1^xvi	4.690 (6)	O3—O7	2.474 (17)
Ti—Si1^vi	3.041 (7)	O4—Ba^xv	4.06 (2)
Ti—Si2	3.220 (11)	O4—Ba^x	3.05 (3)
Ti—Si2^ix	3.241 (11)	O4—Ba^ix	4.10 (2)
Ti—Si2^v	4.742 (9)	O4—Ba^v	3.01 (3)
Ti—O1	2.13 (3)	O4—Ti	1.641 (8)
Ti—O1^xvi	4.05 (3)	O4—Ti^xviii	4.327 (10)
Ti—O1^ix	3.80 (2)	O4—Si1^xvi	3.852 (12)
Ti—O2	2.002 (19)	O4—Si1^v	3.241 (12)
Ti—O2^xvii	4.185 (19)	O4—Si2^xvi	3.67 (2)
Ti—O2^ix	3.603 (17)	O4—Si2^v	3.51 (2)
Ti—O3	4.240 (17)	O4—O1	2.91 (3)
Ti—O3^x	4.399 (16)	O4—O1^xvi	3.20 (4)
Ti—O3^vi	3.977 (14)	O4—O2	2.77 (3)
Ti—O4	1.641 (8)	O4—O2^xvii	3.42 (3)
Ti—O4^xviii	4.327 (10)	O4—O3^xvi	3.40 (2)
Ti—O5^xix	4.207 (17)	O4—O3^v	3.25 (2)
Ti—O5^x	4.366 (15)	O4—O4^xviii	3.79 (2)
Ti—O5^xiii	4.074 (15)	O4—O5^xvi	3.67 (2)
Ti—O5^vi	4.281 (14)	O4—O5^v	3.04 (2)
Ti—O6^x	3.991 (9)	O4—O6^vi	2.901 (14)
Ti—O6^xvi	4.145 (10)	O4—O7^x	2.797 (13)
Ti—O6^vi	1.931 (11)	O4—O7^v	3.198 (15)
Ti—O7^x	1.946 (11)	O5—Ba	4.988 (15)
Ti—O7^vi	2.908 (12)	O5—Ba^viii	3.319 (17)
Si1—Ba	4.098 (7)	O5—Ba^xi	4.793 (14)
Si1—Ba^viii	3.602 (7)	O5—Baⁱⁱ	3.434 (17)
Si1—Baⁱⁱ	3.968 (8)	O5—Ba^xiii	4.994 (16)
Si1—Ba^v	3.949 (8)	O5—Ti^xx	4.207 (17)
Si1—Ti^viii	3.448 (6)	O5—Ti^viii	4.366 (15)
Si1—Ti^xvii	4.690 (6)	O5—Ti^xiii	4.074 (15)
Si1—Tiⁱⁱⁱ	3.041 (7)	O5—Tiⁱⁱⁱ	4.281 (14)
Si1—Si1^xiii	4.479 (12)	O5—Si1	1.609 (11)
Si1—Si2	3.189 (9)	O5—Si1^viii	4.027 (17)
Si1—Si2^viii	3.590 (9)	O5—Si1^xiii	3.857 (19)
Si1—Si2^xiii	3.211 (8)	O5—Si2	3.875 (17)
Si1—Si2ⁱⁱⁱ	4.164 (8)	O5—Si2^viii	3.705 (17)
Si1—O1	4.04 (2)	O5—Si2^xiii	1.692 (13)
Si1—O1^viii	3.89 (2)	O5—O1^xiii	2.239 (19)
Si1—O1^xiii	3.74 (2)	O5—O2^xx	2.463 (19)
Si1—O1ⁱⁱⁱ	3.64 (3)	O5—O3	2.699 (12)
Si1—O2^xx	3.784 (17)	O5—O3^viii	3.320 (11)
Si1—O2^viii	3.807 (17)	O5—O3^xiii	2.638 (13)
Si1—O2ⁱⁱⁱ	3.442 (19)	O5—O4^xvii	3.67 (2)
Si1—O3	1.658 (13)	O5—O4^iv	3.04 (2)
Si1—O3^viii	3.901 (16)	O5—O6	2.932 (18)
Si1—O3^xiii	3.754 (17)	O5—O6^viii	3.79 (2)
Si1—O4^xvii	3.852 (12)	O5—O7	2.846 (17)
Si1—O4^iv	3.241 (12)	O5—O7^viii	3.35 (2)
Si1—O5	1.609 (11)	O6—Ba^xxii	4.971 (14)
Si1—O5^x	4.027 (17)	O6—Ba	5.073 (10)
Si1—O5^xiii	3.857 (19)	O6—Ba^viii	3.185 (16)
Si1—O6	1.652 (11)	O6—Ba^v	2.844 (15)
Si1—O6^xxi	4.022 (11)	O6—Ti^viii	3.991 (9)
Si1—O7	1.626 (10)	O6—Ti^xvii	4.145 (10)
Si2—Ba	3.785 (7)	O6—Tiⁱⁱⁱ	1.931 (11)
Si2—Ba^xv	4.203 (7)	O6—Si1	1.652 (11)
Si2—Ba^v	3.706 (9)	O6—Si1^xxi	4.022 (11)
Si2—Ba^vi	3.822 (9)	O6—Si2	3.833 (13)
Si2—Ti	3.220 (11)	O6—Si2^viii	3.824 (15)
Si2—Ti^ix	3.241 (11)	O6—Si2ⁱⁱⁱ	3.758 (16)
Si2—Ti^iv	4.742 (9)	O6—O1ⁱⁱⁱ	2.66 (3)
Si2—Si1	3.189 (9)	O6—O2ⁱⁱⁱ	2.97 (2)
Si2—Si1^x	3.590 (9)	O6—O3	2.333 (16)
Si2—Si1^xiii	3.211 (8)	O6—O4ⁱⁱⁱ	2.901 (14)
Si2—Si1^vi	4.164 (8)	O6—O5	2.932 (18)
Si2—Si2^xiii	4.572 (12)	O6—O5^x	3.79 (2)
Si2—O1	1.591 (15)	O6—O6^xxi	2.927 (18)
Si2—O2^ix	1.563 (14)	O6—O7	2.480 (11)
Si2—O3	1.588 (12)	O6—O7^xxiii	3.737 (16)
Si2—O3^xiii	3.839 (18)	O7—Ba	3.052 (13)
Si2—O3^vi	4.128 (17)	O7—Ba^viii	4.829 (12)
Si2—O4^xvii	3.67 (2)	O7—Baⁱⁱ	3.571 (13)
Si2—O4^iv	3.51 (2)	O7—Ba^v	4.572 (11)
Si2—O5	3.875 (17)	O7—Ti^viii	1.946 (11)
Si2—O5^x	3.705 (17)	O7—Tiⁱⁱⁱ	2.908 (12)
Si2—O5^xiii	1.692 (13)	O7—Si1	1.626 (10)
Si2—O6	3.833 (13)	O7—Si2	3.792 (13)
Si2—O6^x	3.824 (15)	O7—Si2^viii	3.424 (15)
Si2—O6^vi	3.758 (16)	O7—Si2ⁱⁱⁱ	3.100 (14)
Si2—O7	3.792 (13)	O7—O1^viii	3.09 (2)
Si2—O7^x	3.424 (15)	O7—O1ⁱⁱⁱ	3.15 (3)
Si2—O7^vi	3.100 (14)	O7—O2^viii	2.33 (2)
O1—Ba^xv	3.014 (18)	O7—O2ⁱⁱⁱ	3.47 (2)
O1—Ba^v	2.97 (2)	O7—O3	2.474 (17)
O1—Ba^vi	4.784 (19)	O7—O4^viii	2.797 (13)
O1—Ti	2.13 (3)	O7—O4^iv	3.198 (15)
O1—Ti^xvii	4.05 (3)	O7—O5	2.846 (17)
O1—Ti^ix	3.80 (2)	O7—O5^x	3.35 (2)
O1—Si1	4.04 (2)	O7—O6	2.480 (11)
O1—Si1^x	3.89 (2)	O7—O6^xxiii	3.737 (16)
O1—Si1^xiii	3.74 (2)	O7—O7^xxiii	3.56 (3)
O1—Si1^vi	3.64 (3)

Ti^viii—Ba—Ti^xxiv	90.82 (7)	Ba^xxvi—Ti—O6^xxv	18.5 (5)
Ti^viii—Ba—O1^vii	75.4 (5)	Ba^xxvi—Ti—O7^x	129.6 (4)
Ti^viii—Ba—O1^xxiv	96.4 (5)	O1—Ti—O2	161.1 (3)
Ti^viii—Ba—O2^viii	33.9 (3)	O1—Ti—O4	100.0 (13)
Ti^viii—Ba—O4^viii	27.28 (18)	O1—Ti—O6^xxv	47.1 (7)
Ti^viii—Ba—O4^xxiv	87.8 (4)	O1—Ti—O7^x	98.7 (6)
Ti^viii—Ba—O6^xxiv	97 (3)	O2—Ti—O4	98.3 (13)
Ti^viii—Ba—O7	33.0 (2)	O2—Ti—O6^xxv	132.9 (7)
Ti^xxiv—Ba—O1^vii	131.2 (4)	O2—Ti—O7^x	72.1 (7)
Ti^xxiv—Ba—O1^xxiv	5.7 (5)	O4—Ti—O6^xxv	103.3 (6)
Ti^xxiv—Ba—O2^viii	120.3 (4)	O4—Ti—O7^x	102.1 (6)
Ti^xxiv—Ba—O4^viii	82.1 (4)	O6^xxv—Ti—O7^x	139.2 (5)
Ti^xxiv—Ba—O4^xxiv	5.3 (4)	O3—Si1—O5	111.4 (5)
Ti^xxiv—Ba—O6^xxiv	6.1 (2)	O3—Si1—O6	89.6 (8)
Ti^xxiv—Ba—O7	74.7 (3)	O3—Si1—O7	97.8 (7)
O1^vii—Ba—O1^xxiv	133.3 (5)	O5—Si1—O6	128.0 (10)
O1^vii—Ba—O2^viii	70.0 (4)	O5—Si1—O7	123.3 (9)
O1^vii—Ba—O4^viii	63.8 (6)	O6—Si1—O7	98.3 (6)
O1^vii—Ba—O4^xxiv	134.4 (5)	O1—Si2—O2^ix	121.9 (9)
O1^vii—Ba—O6^xxiv	132.8 (4)	O1—Si2—O3	102.9 (11)
O1^vii—Ba—O7	107.6 (6)	O1—Si2—O5^xiii	85.9 (8)
O1^xxiv—Ba—O2^viii	125.6 (3)	O2^ix—Si2—O3	129.7 (9)
O1^xxiv—Ba—O4^viii	87.6 (5)	O2^ix—Si2—O5^xiii	98.3 (9)
O1^xxiv—Ba—O4^xxiv	9.4 (5)	O3—Si2—O5^xiii	107.0 (6)
O1^xxiv—Ba—O6^xxiv	90.2 (4)	Ba^xv—O1—Ba^v	112.2 (6)
O1^xxiv—Ba—O7	79.7 (5)	Ba^xv—O1—Ti	97.1 (6)
O2^viii—Ba—O4^viii	56.5 (4)	Ba^xv—O1—Si2	129.1 (10)
O2^viii—Ba—O4^xxiv	116.3 (4)	Ba^xxvi—O1—Ti	143.1 (6)
O2^viii—Ba—O6^xxiv	125.9 (4)	Ba^xxvi—O1—Si2	88.5 (10)
O2^viii—Ba—O7	46.7 (4)	Ti—O1—Si2	119.1 (13)
O4^viii—Ba—O4^xxiv	81.7 (8)	Ba^x—O2—Ti	95.4 (6)
O4^viii—Ba—O6^xxiv	87.5 (5)	Ba^x—O2—Si2^ix	121.1 (8)
O4^viii—Ba—O7	54.6 (3)	Ti—O2—Si2^ix	130.4 (11)
O4^xxiv—Ba—O6^xxiv	10.1 (4)	Si1—O3—Si2	158.6 (12)
O4^xxiv—Ba—O7	70.3 (3)	Ba^x—O4—Ba^v	102.7 (3)
O6^xxiv—Ba—O7	80.1 (4)	Ba^x—O4—Ti	94.4 (10)
Ba^x—Ti—Ba^v	83.08 (7)	Ba^xxvi—O4—Ti	79.3 (10)
Ba^x—Ti—O1	138.5 (6)	Si1—O5—Si2^xiii	153.1 (12)
Ba^x—Ti—O2	50.6 (5)	Ba^xxvi—O6—Ti^xxvii	17.2 (8)
Ba^x—Ti—O4	58.3 (9)	Ba^xxvi—O6—Si1	65.7 (7)
Ba^x—Ti—O6^xxv	160.1 (6)	Ti^xxvii—O6—Si1	62.2 (5)
Ba^x—Ti—O7^x	58.7 (4)	Ba—O7—Ti^viii	88.3 (4)
Ba^xxvi—Ti—O1	31.3 (6)	Ba—O7—Si1	119.2 (6)
Ba^xxvi—Ti—O2	151.6 (5)	Ti^viii—O7—Si1	149.6 (9)
Ba^xxvi—Ti—O4	94.7 (9)

Symmetry codes: (i) −x, −y, −z+1; (ii) −x, −y+1, −z+1; (iii) x−1/2, −y+1/2, z−1/2; (iv) x−1/2, −y+1/2, z+1/2; (v) x+1/2, −y+1/2, z−1/2; (vi) x+1/2, −y+1/2, z+1/2; (vii) x−1, y, z; (viii) −x+1/2, y+1/2, −z+1/2; (ix) −x+1, −y, −z+1; (x) −x+1/2, y−1/2, −z+1/2; (xi) −x+1/2, y+1/2, −z+3/2; (xii) −x+1/2, y−1/2, −z+3/2; (xiii) −x+1, −y+1, −z+1; (xiv) x, y, z+1; (xv) x+1, y, z; (xvi) −x+3/2, y−1/2, −z+1/2; (xvii) −x+3/2, y+1/2, −z+1/2; (xviii) −x+1, −y, −z; (xix) x, y−1, z; (xx) x, y+1, z; (xxi) −x+1, −y+1, −z; (xxii) x, y, z−1; (xxiii) −x, −y+1, −z; (xxiv) x+1/2, −y+3/2, z+3/2; (xxv) x+3/2, −y+3/2, z+3/2; (xxvi) x+3/2, −y+3/2, z+1/2; (xxvii) x+1/2, −y+3/2, z+1/2.

(BATISI2O7D_Triclinic) top

Crystal data top

BaO₇Si₂Ti	β = 100.3679 (3)°
M_r = 353.39	γ = 89.9368 (3)°
Triclinic, P1	V = 588.39 (1) Å³
Hall symbol: -P 1	Z = 4
a = 7.99385 (4) Å	D_x = 4 Mg m⁻³
b = 10.01017 (5) Å	Synchrotron radiation, λ = 0.70448 Å
c = 7.47514 (4) Å	T = 295 K
α = 90.0836 (3)°	?, ? × ? × ? mm

Data collection top

Radiation source: synchrotron

2θ_min = 0.505°, 2θ_max = 38.001°, 2θ_step = 0.002°

Refinement top

Least-squares matrix: full	18749 data points
R_p = 0.082	Profile function: CW Profile function number 2 with 18 terms Profile coefficients for Simpson's rule integration of pseudovoigt function C.J. Howard (1982). J. Appl. Cryst.,15,615-620. P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Peak tails are ignored where the intensity is below 0.0001 times the peak
R_wp = 0.107	109 parameters
R_exp = 0.028	16 restraints
R(F²) = 0.08716	(Δ/σ)_max = 0.17
χ² = 14.900	Background function: GSAS Background function number 1 with 18 terms. Shifted Chebyshev function of 1st kind

Crystal data top

BaO₇Si₂Ti	β = 100.3679 (3)°
M_r = 353.39	γ = 89.9368 (3)°
Triclinic, P1	V = 588.39 (1) Å³
a = 7.99385 (4) Å	Z = 4
b = 10.01017 (5) Å	Synchrotron radiation, λ = 0.70448 Å
c = 7.47514 (4) Å	T = 295 K
α = 90.0836 (3)°	?, ? × ? × ? mm

Data collection top

2θ_min = 0.505°, 2θ_max = 38.001°, 2θ_step = 0.002°

Refinement top

R_p = 0.082	18749 data points
R_wp = 0.107	109 parameters
R_exp = 0.028	16 restraints
R(F²) = 0.08716	(Δ/σ)_max = 0.17
χ² = 14.900

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ba1t	0.0064 (7)	0.2643 (7)	0.5059 (8)	0.032 (2)*
Ba2t	0.5018 (7)	0.7632 (6)	0.0080 (8)	0.027 (2)*
Ti1t	0.6503 (11)	−0.0007 (13)	0.3457 (13)	0.004 (1)*
Ti2t	−0.1343 (12)	0.4990 (14)	0.1462 (15)	0.014 (1)*
Si1t	0.3021 (15)	0.5210 (14)	0.2355 (13)	0.004 (2)*
Si2t	0.4819 (18)	0.2800 (16)	0.4752 (19)	0.011 (2)*
Si3t	0.2103 (14)	−0.0218 (14)	0.2356 (14)	0.004 (3)*
Si4t	−0.0300 (16)	0.7777 (15)	−0.0125 (19)	0.004 (2)*
O1t	0.606 (3)	0.197 (2)	0.359 (3)	0.004 (2)*
O2t	0.641 (3)	−0.188 (2)	0.438 (4)	0.004 (2)*
O3t	0.363 (4)	0.382 (3)	0.340 (4)	0.013 (3)*
O4t	0.714 (5)	−0.004 (4)	0.156 (5)	0.004 (3)*
O5t	0.392 (4)	0.640 (3)	0.361 (4)	0.008 (3)*
O6t	0.342 (3)	0.527 (3)	0.028 (2)	0.011 (1)*
O7t	0.1103 (19)	0.536 (4)	0.258 (4)	0.013 (4)*
O8t	−0.168 (3)	0.700 (2)	0.076 (4)	0.007 (2)*
O9t	−0.064 (3)	0.315 (3)	0.137 (4)	0.032 (3)*
O10t	0.102 (4)	0.854 (3)	0.147 (4)	0.010 (5)*
O11t	−0.213 (5)	0.503 (5)	0.333 (5)	0.004 (3)*
O12t	0.139 (5)	0.124 (3)	0.162 (5)	0.038 (3)*
O13t	0.153 (4)	0.970 (3)	0.431 (2)	0.018 (1)*
O14t	0.415 (2)	0.972 (4)	0.266 (4)	0.037 (1)*

Geometric parameters (Å, º) top

Ba1t—Ba1tⁱ	5.294 (13)	O1t—Ba2t^viii	2.75 (3)
Ba1t—Ba1tⁱⁱ	4.720 (13)	O1t—Ti1t	2.01 (3)
Ba1t—Ba2tⁱⁱⁱ	5.071 (8)	O1t—Si2t	1.66 (3)
Ba1t—Ba2t^iv	4.857 (8)	O1t—Si3t^vi	3.58 (3)
Ba1t—Ti1t^v	3.919 (13)	O1t—O2t^vi	2.70 (2)
Ba1t—Ti1t^vi	3.824 (12)	O1t—O3t	2.67 (3)
Ba1t—Ti2t	3.596 (15)	O1t—O4t	2.75 (4)
Ba1t—Ti2tⁱⁱ	3.529 (14)	O1t—O5t^iv	2.65 (3)
Ba1t—Si1t	4.245 (13)	O1t—O13t^iv	2.80 (4)
Ba1t—Si1tⁱⁱ	4.016 (12)	O1t—O14t^vii	2.73 (4)
Ba1t—Si2t^v	4.160 (15)	O2t—Ba1t^vi	2.88 (2)
Ba1t—Si2t	3.852 (15)	O2t—Ba2t^vii	3.24 (3)
Ba1t—Si3t	4.013 (13)	O2t—Ti1t	2.01 (2)
Ba1t—Si3tⁱ	3.723 (13)	O2t—Ti1t^vi	3.60 (2)
Ba1t—Si4tⁱⁱⁱ	3.750 (15)	O2t—Si2t^vi	1.57 (3)
Ba1t—Si4tⁱⁱ	3.782 (15)	O2t—Si3t^vi	3.28 (3)
Ba1t—O1t^v	3.27 (2)	O2t—O1t^vi	2.70 (2)
Ba1t—O2t^vi	2.88 (2)	O2t—O3t^vi	2.56 (3)
Ba1t—O3t	3.51 (4)	O2t—O4t	2.95 (4)
Ba1t—O4t^v	4.16 (4)	O2t—O5t^vii	2.61 (3)
Ba1t—O4t^vi	4.02 (4)	O2t—O13t^iv	2.81 (4)
Ba1t—O5tⁱⁱ	3.63 (4)	O2t—O14t^vii	2.58 (4)
Ba1t—O7t	3.47 (3)	O2t—O14t^iv	3.18 (4)
Ba1t—O7tⁱⁱ	2.93 (3)	O3t—Ba1t	3.51 (4)
Ba1t—O8tⁱⁱ	3.18 (3)	O3t—Ba2t^viii	3.32 (4)
Ba1t—O9t	2.76 (3)	O3t—Si1t	1.63 (3)
Ba1t—O10tⁱⁱ	3.12 (3)	O3t—Si2t	1.62 (3)
Ba1t—O11t	3.10 (5)	O3t—O1t	2.67 (3)
Ba1t—O11tⁱⁱ	2.98 (4)	O3t—O2t^vi	2.56 (3)
Ba1t—O12t	3.27 (4)	O3t—O5t	2.59 (4)
Ba1t—O13t^vii	3.26 (3)	O3t—O5t^iv	2.70 (4)
Ba1t—O13tⁱⁱ	2.75 (3)	O3t—O6t	2.73 (3)
Ba2t—Ba1tⁱⁱⁱ	5.071 (8)	O3t—O7t	2.53 (3)
Ba2t—Ba1t^iv	4.857 (8)	O3t—O11tⁱⁱ	3.13 (5)
Ba2t—Ba2t^viii	5.271 (13)	O4t—Ba1t^xi	4.16 (4)
Ba2t—Ba2t^ix	4.742 (13)	O4t—Ba1t^vi	4.02 (4)
Ba2t—Ti1t^x	3.503 (13)	O4t—Ba2t^vii	2.98 (4)
Ba2t—Ti1t^viii	3.603 (14)	O4t—Ba2t^viii	3.08 (5)
Ba2t—Ti2t^xi	3.928 (13)	O4t—Ti1t	1.60 (3)
Ba2t—Ti2tⁱⁱⁱ	3.955 (14)	O4t—Si3t^xii	3.10 (3)
Ba2t—Si1t	3.510 (13)	O4t—Si4t^xiv	3.38 (4)
Ba2t—Si1t^viii	3.856 (13)	O4t—O1t	2.75 (4)
Ba2t—Si2t^viii	3.663 (15)	O4t—O2t	2.95 (4)
Ba2t—Si2t^iv	3.866 (15)	O4t—O12t^xii	3.07 (5)
Ba2t—Si3t^x	3.790 (12)	O4t—O13t^iv	3.10 (4)
Ba2t—Si3t^viii	4.104 (13)	O4t—O14t^vii	2.68 (4)
Ba2t—Si4t	4.229 (13)	O4t—O14t^viii	3.15 (5)
Ba2t—Si4t^xi	3.776 (13)	O5t—Ba1tⁱⁱ	3.63 (4)
Ba2t—O1t^viii	2.75 (3)	O5t—Ba2t	3.18 (3)
Ba2t—O2t^x	3.24 (3)	O5t—Si1t	1.60 (3)
Ba2t—O3t^viii	3.32 (4)	O5t—Si2t^iv	1.65 (3)
Ba2t—O4t^x	2.98 (4)	O5t—O1t^iv	2.65 (3)
Ba2t—O4t^viii	3.08 (5)	O5t—O2t^x	2.61 (3)
Ba2t—O5t	3.18 (3)	O5t—O3t	2.59 (4)
Ba2t—O6t	2.71 (3)	O5t—O3t^iv	2.70 (4)
Ba2t—O6t^viii	3.19 (3)	O5t—O6t	2.70 (3)
Ba2t—O8t^xi	2.67 (3)	O5t—O7t	2.47 (3)
Ba2t—O9tⁱⁱⁱ	3.56 (3)	O6t—Ba2t	2.71 (3)
Ba2t—O10t	3.65 (4)	O6t—Ba2t^viii	3.19 (3)
Ba2t—O11t^xi	3.99 (4)	O6t—Ti2tⁱⁱⁱ	1.93 (3)
Ba2t—O11tⁱⁱⁱ	4.10 (4)	O6t—Si1t	1.643 (12)
Ba2t—O12t^viii	3.53 (4)	O6t—O3t	2.73 (3)
Ba2t—O14t	3.01 (4)	O6t—O5t	2.70 (3)
Ba2t—O14t^ix	3.49 (4)	O6t—O6t^viii	2.68 (5)
Ti1t—Ba1t^xi	3.919 (13)	O6t—O7t	2.75 (3)
Ti1t—Ba1t^vi	3.824 (12)	O6t—O8tⁱⁱⁱ	2.70 (4)
Ti1t—Ba2t^vii	3.503 (13)	O6t—O9tⁱⁱⁱ	2.82 (4)
Ti1t—Ba2t^viii	3.603 (14)	O6t—O11tⁱⁱⁱ	2.72 (4)
Ti1t—Ti1t^vi	3.618 (16)	O7t—Ba1t	3.47 (3)
Ti1t—Si2t	3.33 (2)	O7t—Ba1tⁱⁱ	2.93 (3)
Ti1t—Si2t^vi	3.354 (18)	O7t—Ti2t	2.02 (2)
Ti1t—Si3t	3.472 (15)	O7t—Ti2tⁱⁱⁱ	3.08 (3)
Ti1t—Si3t^vi	3.136 (14)	O7t—Si1t	1.580 (13)
Ti1t—O1t	2.01 (3)	O7t—Si4t	3.23 (4)
Ti1t—O2t	2.01 (2)	O7t—O3t	2.53 (3)
Ti1t—O2t^vi	3.60 (2)	O7t—O5t	2.47 (3)
Ti1t—O4t	1.60 (3)	O7t—O6t	2.75 (3)
Ti1t—O13t^iv	2.10 (3)	O7t—O8t	2.90 (4)
Ti1t—O14t^vii	1.89 (2)	O7t—O9t	2.69 (4)
Ti1t—O14t^iv	3.05 (3)	O7t—O11t	2.76 (4)
Ti2t—Ba1t	3.596 (15)	O7t—O11tⁱⁱ	3.04 (5)
Ti2t—Ba1tⁱⁱ	3.529 (14)	O8t—Ba1tⁱⁱ	3.18 (3)
Ti2t—Ba2t^v	3.928 (13)	O8t—Ba2t^v	2.67 (3)
Ti2t—Ba2tⁱⁱⁱ	3.955 (14)	O8t—Ti2t	2.08 (3)
Ti2t—Ti2tⁱⁱⁱ	3.329 (17)	O8t—Ti2tⁱⁱⁱ	3.74 (3)
Ti2t—Si1t	3.439 (16)	O8t—Si1tⁱⁱⁱ	3.25 (3)
Ti2t—Si1tⁱⁱⁱ	2.933 (15)	O8t—Si4t	1.59 (3)
Ti2t—Si4t	3.203 (19)	O8t—O6tⁱⁱⁱ	2.70 (4)
Ti2t—Si4tⁱⁱⁱ	3.29 (2)	O8t—O7t	2.90 (4)
Ti2t—O6tⁱⁱⁱ	1.93 (3)	O8t—O9tⁱⁱⁱ	2.66 (3)
Ti2t—O7t	2.02 (2)	O8t—O10t	2.64 (3)
Ti2t—O7tⁱⁱⁱ	3.08 (3)	O8t—O11t	2.82 (5)
Ti2t—O8t	2.08 (3)	O8t—O12tⁱⁱⁱ	2.55 (4)
Ti2t—O8tⁱⁱⁱ	3.74 (3)	O9t—Ba1t	2.76 (3)
Ti2t—O9t	1.93 (3)	O9t—Ba2tⁱⁱⁱ	3.56 (3)
Ti2t—O9tⁱⁱⁱ	3.42 (3)	O9t—Ti2t	1.93 (3)
Ti2t—O11t	1.63 (3)	O9t—Ti2tⁱⁱⁱ	3.42 (3)
Si1t—Ba1t	4.245 (13)	O9t—Si1t	3.55 (3)
Si1t—Ba1tⁱⁱ	4.016 (12)	O9t—Si1tⁱⁱⁱ	3.48 (4)
Si1t—Ba2t	3.510 (13)	O9t—Si4tⁱⁱⁱ	1.59 (3)
Si1t—Ba2t^viii	3.856 (13)	O9t—O6tⁱⁱⁱ	2.82 (4)
Si1t—Ti2t	3.439 (16)	O9t—O7t	2.69 (4)
Si1t—Ti2tⁱⁱⁱ	2.933 (15)	O9t—O8tⁱⁱⁱ	2.66 (3)
Si1t—Si2t	3.190 (18)	O9t—O10tⁱⁱⁱ	2.69 (3)
Si1t—Si2t^iv	3.206 (16)	O9t—O11t	2.77 (4)
Si1t—Si4t	3.91 (2)	O9t—O12t	2.49 (3)
Si1t—Si4tⁱⁱⁱ	3.89 (2)	O10t—Ba1tⁱⁱ	3.12 (3)
Si1t—O3t	1.63 (3)	O10t—Ba2t	3.65 (4)
Si1t—O5t	1.60 (3)	O10t—Si3t^x	1.589 (12)
Si1t—O6t	1.643 (12)	O10t—Si4t	1.63 (3)
Si1t—O7t	1.580 (13)	O10t—O8t	2.64 (3)
Si1t—O8tⁱⁱⁱ	3.25 (3)	O10t—O9tⁱⁱⁱ	2.69 (3)
Si1t—O9t	3.55 (3)	O10t—O12t^x	2.72 (4)
Si1t—O9tⁱⁱⁱ	3.48 (4)	O10t—O12tⁱⁱⁱ	2.74 (4)
Si1t—O11tⁱⁱ	3.44 (3)	O10t—O13t	2.39 (3)
Si2t—Ba1t	3.852 (15)	O10t—O14t	2.77 (3)
Si2t—Ba1t^xi	4.160 (15)	O11t—Ba1t	3.10 (5)
Si2t—Ba2t^viii	3.663 (15)	O11t—Ba1tⁱⁱ	2.98 (4)
Si2t—Ba2t^iv	3.866 (15)	O11t—Ba2t^v	3.99 (4)
Si2t—Ti1t	3.33 (2)	O11t—Ba2tⁱⁱⁱ	4.10 (4)
Si2t—Ti1t^vi	3.354 (18)	O11t—Ti2t	1.63 (3)
Si2t—Si1t	3.190 (18)	O11t—Si1tⁱⁱ	3.44 (3)
Si2t—Si1t^iv	3.206 (16)	O11t—Si2tⁱⁱ	3.54 (4)
Si2t—Si3t	3.96 (2)	O11t—O3tⁱⁱ	3.13 (5)
Si2t—Si3t^vi	3.94 (2)	O11t—O6tⁱⁱⁱ	2.72 (4)
Si2t—O1t	1.66 (3)	O11t—O7t	2.76 (4)
Si2t—O2t^vi	1.57 (3)	O11t—O7tⁱⁱ	3.04 (5)
Si2t—O3t	1.62 (3)	O11t—O8t	2.82 (5)
Si2t—O5t^iv	1.65 (3)	O11t—O9t	2.77 (4)
Si2t—O11tⁱⁱ	3.54 (4)	O12t—Ba1t	3.27 (4)
Si2t—O14t^vii	3.45 (4)	O12t—Ba2t^viii	3.53 (4)
Si2t—O14t^iv	3.20 (4)	O12t—Si3t	1.63 (3)
Si3t—Ba1t	4.013 (13)	O12t—Si4tⁱⁱⁱ	1.62 (3)
Si3t—Ba1tⁱ	3.723 (13)	O12t—O4t^xii	3.07 (5)
Si3t—Ba2t^vii	3.790 (12)	O12t—O8tⁱⁱⁱ	2.55 (4)
Si3t—Ba2t^viii	4.104 (13)	O12t—O9t	2.49 (3)
Si3t—Ti1t	3.472 (15)	O12t—O10t^vii	2.72 (4)
Si3t—Ti1t^vi	3.136 (14)	O12t—O10tⁱⁱⁱ	2.74 (4)
Si3t—Si2t	3.96 (2)	O12t—O13t^vii	2.53 (4)
Si3t—Si2t^vi	3.94 (2)	O12t—O14t^vii	2.68 (4)
Si3t—Si4t^vii	3.142 (16)	O13t—Ba1t^x	3.26 (3)
Si3t—Si4tⁱⁱⁱ	3.157 (19)	O13t—Ba1tⁱⁱ	2.75 (3)
Si3t—O1t^vi	3.58 (3)	O13t—Ti1t^iv	2.10 (3)
Si3t—O2t^vi	3.28 (3)	O13t—Si3t^x	1.61 (3)
Si3t—O4t^xii	3.10 (3)	O13t—O1t^iv	2.80 (4)
Si3t—O10t^vii	1.589 (12)	O13t—O2t^iv	2.81 (4)
Si3t—O12t	1.63 (3)	O13t—O4t^iv	3.10 (4)
Si3t—O13t^vii	1.612 (12)	O13t—O10t	2.39 (3)
Si3t—O14t^vii	1.613 (13)	O13t—O12t^x	2.53 (4)
Si4t—Ba1tⁱⁱⁱ	3.750 (15)	O13t—O13t^xv	2.88 (5)
Si4t—Ba1tⁱⁱ	3.782 (15)	O13t—O14t	2.62 (3)
Si4t—Ba2t^v	3.776 (13)	O14t—Ba2t	3.01 (4)
Si4t—Ba2t	4.229 (13)	O14t—Ba2t^ix	3.49 (4)
Si4t—Ti2t	3.203 (19)	O14t—Ti1t^x	1.89 (2)
Si4t—Ti2tⁱⁱⁱ	3.29 (2)	O14t—Ti1t^iv	3.05 (3)
Si4t—Si1t	3.91 (2)	O14t—Si2t^x	3.45 (4)
Si4t—Si1tⁱⁱⁱ	3.89 (2)	O14t—Si2t^iv	3.20 (4)
Si4t—Si3t^x	3.142 (16)	O14t—Si3t^x	1.613 (13)
Si4t—Si3tⁱⁱⁱ	3.157 (19)	O14t—O1t^x	2.73 (4)
Si4t—O4t^xiii	3.38 (4)	O14t—O2t^x	2.58 (4)
Si4t—O7t	3.23 (4)	O14t—O2t^iv	3.18 (4)
Si4t—O8t	1.59 (3)	O14t—O4t^x	2.68 (4)
Si4t—O9tⁱⁱⁱ	1.59 (3)	O14t—O4t^viii	3.15 (5)
Si4t—O10t	1.63 (3)	O14t—O10t	2.77 (3)
Si4t—O12tⁱⁱⁱ	1.62 (4)	O14t—O12t^x	2.68 (4)
O1t—Ba1t^xi	3.27 (2)	O14t—O13t	2.62 (3)

Ti2t—Ba1t—Ti2tⁱⁱ	97.0 (3)	O2t—Ti1t—O14t^vii	82.9 (16)
Ti2t—Ba1t—O2t^vi	116.5 (5)	O4t—Ti1t—O13t^iv	113.3 (16)
Ti2t—Ba1t—O7tⁱⁱ	85.0 (7)	O4t—Ti1t—O14t^vii	100.2 (18)
Ti2t—Ba1t—O9t	32.0 (5)	O13t^iv—Ti1t—O14t^vii	146.4 (11)
Ti2t—Ba1t—O10tⁱⁱ	140.9 (7)	Ba1t—Ti2t—Ba1tⁱⁱ	83.0 (3)
Ti2t—Ba1t—O11t	26.9 (6)	Ba1t—Ti2t—O6tⁱⁱⁱ	122.1 (10)
Ti2t—Ba1t—O11tⁱⁱ	82.4 (8)	Ba1t—Ti2t—O7t	70.1 (10)
Ti2t—Ba1t—O13tⁱⁱ	126.3 (6)	Ba1t—Ti2t—O8t	146.0 (9)
Ti2tⁱⁱ—Ba1t—O2t^vi	85.6 (6)	Ba1t—Ti2t—O9t	49.5 (10)
Ti2tⁱⁱ—Ba1t—O7tⁱⁱ	34.9 (4)	Ba1t—Ti2t—O11t	59.4 (16)
Ti2tⁱⁱ—Ba1t—O9t	126.3 (6)	Ba1tⁱⁱ—Ti2t—O6tⁱⁱⁱ	133.2 (10)
Ti2tⁱⁱ—Ba1t—O10tⁱⁱ	74.3 (4)	Ba1tⁱⁱ—Ti2t—O7t	56.0 (8)
Ti2tⁱⁱ—Ba1t—O11t	81.9 (8)	Ba1tⁱⁱ—Ti2t—O8t	63.0 (9)
Ti2tⁱⁱ—Ba1t—O11tⁱⁱ	27.4 (6)	Ba1tⁱⁱ—Ti2t—O9t	128.3 (11)
Ti2tⁱⁱ—Ba1t—O13tⁱⁱ	121.9 (4)	Ba1tⁱⁱ—Ti2t—O11t	57.4 (15)
O2t^vi—Ba1t—O7tⁱⁱ	120.2 (7)	O6tⁱⁱⁱ—Ti2t—O7t	162.7 (11)
O2t^vi—Ba1t—O9t	102.3 (7)	O6tⁱⁱⁱ—Ti2t—O8t	84.3 (13)
O2t^vi—Ba1t—O10tⁱⁱ	101.0 (8)	O6tⁱⁱⁱ—Ti2t—O9t	93.8 (15)
O2t^vi—Ba1t—O11t	136.7 (8)	O6tⁱⁱⁱ—Ti2t—O11t	99.2 (15)
O2t^vi—Ba1t—O11tⁱⁱ	71.9 (9)	O7t—Ti2t—O8t	90.1 (13)
O2t^vi—Ba1t—O13tⁱⁱ	102.9 (8)	O7t—Ti2t—O9t	85.7 (13)
O7tⁱⁱ—Ba1t—O9t	116.4 (8)	O7t—Ti2t—O11t	97.8 (17)
O7tⁱⁱ—Ba1t—O10tⁱⁱ	66.0 (9)	O8t—Ti2t—O9t	159.6 (11)
O7tⁱⁱ—Ba1t—O11t	60.6 (9)	O8t—Ti2t—O11t	98.2 (18)
O7tⁱⁱ—Ba1t—O11tⁱⁱ	55.7 (8)	O9t—Ti2t—O11t	102.2 (19)
O7tⁱⁱ—Ba1t—O13tⁱⁱ	105.8 (8)	Ba2t—Si1t—O3t	134.5 (14)
O9t—Ba1t—O10tⁱⁱ	149.8 (7)	Ba2t—Si1t—O5t	64.9 (11)
O9t—Ba1t—O11t	56.1 (8)	Ba2t—Si1t—O6t	48.2 (11)
O9t—Ba1t—O11tⁱⁱ	105.0 (9)	Ba2t—Si1t—O7t	121.6 (14)
O9t—Ba1t—O13tⁱⁱ	108.0 (7)	O3t—Si1t—O5t	106.7 (19)
O10tⁱⁱ—Ba1t—O11t	114.8 (9)	O3t—Si1t—O6t	113.1 (18)
O10tⁱⁱ—Ba1t—O11tⁱⁱ	100.3 (7)	O3t—Si1t—O7t	103.9 (19)
O10tⁱⁱ—Ba1t—O13tⁱⁱ	47.6 (5)	O5t—Si1t—O6t	112.6 (16)
O11t—Ba1t—O11tⁱⁱ	78.3 (12)	O5t—Si1t—O7t	102.0 (17)
O11t—Ba1t—O13tⁱⁱ	118.8 (10)	O6t—Si1t—O7t	117.2 (15)
O11tⁱⁱ—Ba1t—O13tⁱⁱ	146.9 (8)	O1t—Si2t—O2t^vi	113.6 (14)
Ti1t^x—Ba2t—Ti1t^viii	96.3 (3)	O1t—Si2t—O3t	109.2 (17)
Ti1t^x—Ba2t—Si1t	104.0 (3)	O1t—Si2t—O5t^iv	106.9 (17)
Ti1t^x—Ba2t—O1t^viii	128.6 (5)	O2t^vi—Si2t—O3t	106.7 (18)
Ti1t^x—Ba2t—O4t^x	27.0 (6)	O2t^vi—Si2t—O5t^iv	108.9 (17)
Ti1t^x—Ba2t—O4t^viii	81.5 (8)	O3t—Si2t—O5t^iv	112 (2)
Ti1t^x—Ba2t—O6t	130.7 (4)	O10t^vii—Si3t—O12t	116 (2)
Ti1t^x—Ba2t—O8t^xi	80.1 (6)	O10t^vii—Si3t—O13t^vii	96.5 (16)
Ti1t^x—Ba2t—O14t	32.6 (4)	O10t^vii—Si3t—O14t^vii	120 (2)
Ti1t^viii—Ba2t—Si1t	133.6 (3)	O12t—Si3t—O13t^vii	103 (2)
Ti1t^viii—Ba2t—O1t^viii	33.7 (5)	O12t—Si3t—O14t^vii	112 (2)
Ti1t^viii—Ba2t—O4t^x	81.3 (8)	O13t^vii—Si3t—O14t^vii	108.3 (16)
Ti1t^viii—Ba2t—O4t^viii	26.2 (6)	O8t—Si4t—O9tⁱⁱⁱ	113.1 (16)
Ti1t^viii—Ba2t—O6t	121.2 (6)	O8t—Si4t—O10t	109.4 (17)
Ti1t^viii—Ba2t—O8t^xi	119.2 (5)	O8t—Si4t—O12tⁱⁱⁱ	105 (2)
Ti1t^viii—Ba2t—O14t	85.7 (8)	O9tⁱⁱⁱ—Si4t—O10t	112.6 (18)
Si1t—Ba2t—O1t^viii	119.8 (5)	O9tⁱⁱⁱ—Si4t—O12tⁱⁱⁱ	101.8 (19)
Si1t—Ba2t—O4t^x	129.9 (7)	O10t—Si4t—O12tⁱⁱⁱ	115 (2)
Si1t—Ba2t—O4t^viii	117.4 (6)	Ba2t^viii—O1t—Ti1t	97.0 (9)
Si1t—Ba2t—O6t	26.9 (3)	Ba2t^viii—O1t—Si2t	109.9 (13)
Si1t—Ba2t—O8t^xi	105.2 (5)	Ti1t—O1t—Si2t	130.3 (15)
Si1t—Ba2t—O14t	89.6 (7)	Ba1t^vi—O2t—Ti1t	101.5 (7)
O1t^viii—Ba2t—O4t^x	108.0 (9)	Ba1t^vi—O2t—Si2t^vi	117.2 (14)
O1t^viii—Ba2t—O4t^viii	55.8 (7)	Ti1t—O2t—Si2t^vi	139.1 (15)
O1t^viii—Ba2t—O6t	96.7 (6)	Si1t—O3t—Si2t	159 (3)
O1t^viii—Ba2t—O8t^xi	110.2 (7)	Ba2t^vii—O4t—Ba2t^viii	102.9 (12)
O1t^viii—Ba2t—O14t	118.1 (8)	Ba2t^vii—O4t—Ti1t	95.2 (16)
O4t^x—Ba2t—O4t^viii	77.1 (12)	Ba2t^viii—O4t—Ti1t	95.4 (18)
O4t^x—Ba2t—O6t	155.3 (8)	Si1t—O5t—Si2t^iv	161 (3)
O4t^x—Ba2t—O8t^xi	68.8 (10)	Ba2t—O6t—Ti2tⁱⁱⁱ	115.9 (13)
O4t^x—Ba2t—O14t	53.2 (8)	Ba2t—O6t—Si1t	104.9 (13)
O4t^viii—Ba2t—O6t	117.9 (10)	Ti2tⁱⁱⁱ—O6t—Si1t	109.9 (14)
O4t^viii—Ba2t—O8t^xi	136.4 (8)	Ba1tⁱⁱ—O7t—Ti2t	89.1 (8)
O4t^viii—Ba2t—O14t	62.3 (9)	Ba1tⁱⁱ—O7t—Si1t	123.3 (15)
O6t—Ba2t—O8t^xi	103.9 (8)	Ti2t—O7t—Si1t	145.5 (18)
O6t—Ba2t—O14t	114.0 (8)	Ba2t^v—O8t—Ti2t	110.9 (8)
O8t^xi—Ba2t—O14t	112.1 (7)	Ba2t^v—O8t—Si4t	122.6 (15)
Ba2t^vii—Ti1t—Ba2t^viii	83.7 (3)	Ti2t—O8t—Si4t	120.7 (14)
Ba2t^vii—Ti1t—O1t	131.0 (9)	Ba1t—O9t—Ti2t	98.5 (10)
Ba2t^vii—Ti1t—O2t	65.7 (9)	Ba1t—O9t—Si4tⁱⁱⁱ	116.1 (17)
Ba2t^vii—Ti1t—O4t	57.8 (15)	Ti2t—O9t—Si4tⁱⁱⁱ	138 (2)
Ba2t^vii—Ti1t—O13t^iv	141.3 (10)	Ba1tⁱⁱ—O10t—Si3t^x	99.5 (12)
Ba2t^vii—Ti1t—O14t^vii	59.1 (11)	Ba1tⁱⁱ—O10t—Si4t	100.9 (13)
Ba2t^viii—Ti1t—O1t	49.3 (8)	Si3t^x—O10t—Si4t	154 (3)
Ba2t^viii—Ti1t—O2t	147.3 (10)	Ba1t—O11t—Ba1tⁱⁱ	101.7 (12)
Ba2t^viii—Ti1t—O4t	58.5 (17)	Ba1t—O11t—Ti2t	93.7 (18)
Ba2t^viii—Ti1t—O13t^iv	126.2 (10)	Ba1tⁱⁱ—O11t—Ti2t	95.3 (16)
Ba2t^viii—Ti1t—O14t^vii	71.2 (13)	Si3t—O12t—Si4tⁱⁱⁱ	153 (3)
O1t—Ti1t—O2t	152.0 (10)	Ba1tⁱⁱ—O13t—Ti1t^iv	107.2 (11)
O1t—Ti1t—O4t	98.5 (18)	Ba1tⁱⁱ—O13t—Si3t^x	114.6 (15)
O1t—Ti1t—O13t^iv	86.0 (13)	Ti1t^iv—O13t—Si3t^x	114.8 (15)
O1t—Ti1t—O14t^vii	88.9 (15)	Ba2t—O14t—Ti1t^x	88.3 (10)
O2t—Ti1t—O4t	109.2 (19)	Ba2t—O14t—Si3t^x	106.2 (15)
O2t—Ti1t—O13t^iv	86.2 (13)	Ti1t^x—O14t—Si3t^x	166 (2)

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

Experimental details

	(BTS2_Monoclinic)	(BATISI2O7D_Triclinic)
Crystal data
Chemical formula	BaO_6.84Si₂Ti	BaO₇Si₂Ti
M_r	350.88	353.39
Crystal system, space group	Monoclinic, P2₁/n	Triclinic, P1
Temperature (K)	295	295
a, b, c (Å)	7.9836 (3), 10.0084 (4), 7.4795 (3)	7.99385 (4), 10.01017 (5), 7.47514 (4)
α, β, γ (°)	90, 100.321 (3), 90	90.0836 (3), 100.3679 (3), 89.9368 (3)
V (Å³)	587.97 (5)	588.39 (1)
Z	4	4
Radiation type	Synchrotron, λ = 0.70448 Å	Synchrotron, λ = 0.70448 Å
Specimen shape, size (mm)	?, ? × ? × ?	?, ? × ? × ?

Data collection
Diffractometer	?	?
Specimen mounting	?	?
Data collection mode	?	?
Scan method	?	?
2θ values (°)	2θ_min = 0.011 2θ_max = 65.412 2θ_step = 0.044	2θ_min = 0.505 2θ_max = 38.001 2θ_step = 0.002

Refinement
R factors and goodness of fit	R_p = 0.042, R_wp = 0.054, R_exp = 0.006, R(F²) = 0.09784, χ² = 130.188	R_p = 0.082, R_wp = 0.107, R_exp = 0.028, R(F²) = 0.08716, χ² = 14.900
No. of data points	1474	18749
No. of parameters	179	109
No. of restraints	8	16
(Δ/σ)_max	0.04	0.17

Computer programs: GSAS.

Selected geometric parameters (Å, º) for (BTS2_Monoclinic) top

Ba—Baⁱ	4.730 (3)	Si1—O5	1.609 (11)
Ba—Tiⁱⁱ	3.901 (8)	Si1—O6	1.652 (11)
Ba—Tiⁱⁱⁱ	3.570 (8)	Si1—O7	1.626 (10)
Ba—Ti^iv	3.919 (8)	Si2—Ba	3.785 (7)
Ba—Ti^v	3.562 (8)	Si2—Ba^ix	3.706 (9)
Ba—Si1^vi	3.602 (7)	Si2—Ba^x	3.822 (9)
Ba—Si1^v	3.949 (8)	Si2—O1	1.591 (15)
Ba—Si2	3.785 (7)	Si2—O2^iv	1.563 (14)
Ba—Si2^vii	3.822 (9)	Si2—O3	1.588 (12)
Ba—Si2^v	3.706 (9)	Si2—O5^xi	1.692 (13)
Ba—O1ⁱⁱ	3.014 (18)	O1—Ba^viii	3.014 (18)
Ba—O1^v	2.97 (2)	O1—Ba^ix	2.97 (2)
Ba—O2ⁱⁱⁱ	2.773 (18)	O1—Ti	2.13 (3)
Ba—O2^iv	3.195 (15)	O1—Si2	1.591 (15)
Ba—O3^v	3.188 (17)	O2—Ba^vi	2.773 (18)
Ba—O4ⁱⁱⁱ	3.05 (3)	O2—Ba^iv	3.195 (15)
Ba—O4^v	3.01 (3)	O2—Ti	2.002 (19)
Ba—O5^vi	3.319 (17)	O2—Si2^iv	1.563 (14)
Ba—O5ⁱ	3.434 (17)	O3—Ba^ix	3.188 (17)
Ba—O6^vi	3.185 (16)	O3—Si1	1.658 (13)
Ba—O6^v	2.844 (15)	O3—Si2	1.588 (12)
Ba—O7	3.052 (13)	O4—Ba^vi	3.05 (3)
Ti—Ba^viii	3.901 (8)	O4—Ba^ix	3.01 (3)
Ti—Ba^vi	3.570 (8)	O4—Ti	1.641 (8)
Ti—Ba^iv	3.919 (8)	O5—Baⁱⁱⁱ	3.319 (17)
Ti—Ba^ix	3.562 (8)	O5—Baⁱ	3.434 (17)
Ti—Si1^x	3.041 (7)	O5—Si1	1.609 (11)
Ti—O1	2.13 (3)	O5—Si2^xi	1.692 (13)
Ti—O2	2.002 (19)	O6—Baⁱⁱⁱ	3.185 (16)
Ti—O4	1.641 (8)	O6—Ba^ix	2.844 (15)
Ti—O6^x	1.931 (11)	O6—Ti^vii	1.931 (11)
Ti—O7^vi	1.946 (11)	O6—Si1	1.652 (11)
Si1—Baⁱⁱⁱ	3.602 (7)	O7—Ba	3.052 (13)
Si1—Ba^ix	3.949 (8)	O7—Tiⁱⁱⁱ	1.946 (11)
Si1—Ti^vii	3.041 (7)	O7—Si1	1.626 (10)
Si1—O3	1.658 (13)

Tiⁱⁱⁱ—Ba—Ti^xii	90.82 (7)	Ba^xiv—Ti—O6^xiii	18.5 (5)
Tiⁱⁱⁱ—Ba—O1ⁱⁱ	75.4 (5)	Ba^xiv—Ti—O7^vi	129.6 (4)
Tiⁱⁱⁱ—Ba—O1^xii	96.4 (5)	O1—Ti—O2	161.1 (3)
Tiⁱⁱⁱ—Ba—O2ⁱⁱⁱ	33.9 (3)	O1—Ti—O4	100.0 (13)
Tiⁱⁱⁱ—Ba—O4ⁱⁱⁱ	27.28 (18)	O1—Ti—O6^xiii	47.1 (7)
Tiⁱⁱⁱ—Ba—O4^xii	87.8 (4)	O1—Ti—O7^vi	98.7 (6)
Tiⁱⁱⁱ—Ba—O6^xii	97 (3)	O2—Ti—O4	98.3 (13)
Tiⁱⁱⁱ—Ba—O7	33.0 (2)	O2—Ti—O6^xiii	132.9 (7)
Ti^xii—Ba—O1ⁱⁱ	131.2 (4)	O2—Ti—O7^vi	72.1 (7)
Ti^xii—Ba—O1^xii	5.7 (5)	O4—Ti—O6^xiii	103.3 (6)
Ti^xii—Ba—O2ⁱⁱⁱ	120.3 (4)	O4—Ti—O7^vi	102.1 (6)
Ti^xii—Ba—O4ⁱⁱⁱ	82.1 (4)	O6^xiii—Ti—O7^vi	139.2 (5)
Ti^xii—Ba—O4^xii	5.3 (4)	O3—Si1—O5	111.4 (5)
Ti^xii—Ba—O6^xii	6.1 (2)	O3—Si1—O6	89.6 (8)
Ti^xii—Ba—O7	74.7 (3)	O3—Si1—O7	97.8 (7)
O1ⁱⁱ—Ba—O1^xii	133.3 (5)	O5—Si1—O6	128.0 (10)
O1ⁱⁱ—Ba—O2ⁱⁱⁱ	70.0 (4)	O5—Si1—O7	123.3 (9)
O1ⁱⁱ—Ba—O4ⁱⁱⁱ	63.8 (6)	O6—Si1—O7	98.3 (6)
O1ⁱⁱ—Ba—O4^xii	134.4 (5)	O1—Si2—O2^iv	121.9 (9)
O1ⁱⁱ—Ba—O6^xii	132.8 (4)	O1—Si2—O3	102.9 (11)
O1ⁱⁱ—Ba—O7	107.6 (6)	O1—Si2—O5^xi	85.9 (8)
O1^xii—Ba—O2ⁱⁱⁱ	125.6 (3)	O2^iv—Si2—O3	129.7 (9)
O1^xii—Ba—O4ⁱⁱⁱ	87.6 (5)	O2^iv—Si2—O5^xi	98.3 (9)
O1^xii—Ba—O4^xii	9.4 (5)	O3—Si2—O5^xi	107.0 (6)
O1^xii—Ba—O6^xii	90.2 (4)	Ba^viii—O1—Ba^ix	112.2 (6)
O1^xii—Ba—O7	79.7 (5)	Ba^viii—O1—Ti	97.1 (6)
O2ⁱⁱⁱ—Ba—O4ⁱⁱⁱ	56.5 (4)	Ba^viii—O1—Si2	129.1 (10)
O2ⁱⁱⁱ—Ba—O4^xii	116.3 (4)	Ba^xiv—O1—Ti	143.1 (6)
O2ⁱⁱⁱ—Ba—O6^xii	125.9 (4)	Ba^xiv—O1—Si2	88.5 (10)
O2ⁱⁱⁱ—Ba—O7	46.7 (4)	Ti—O1—Si2	119.1 (13)
O4ⁱⁱⁱ—Ba—O4^xii	81.7 (8)	Ba^vi—O2—Ti	95.4 (6)
O4ⁱⁱⁱ—Ba—O6^xii	87.5 (5)	Ba^vi—O2—Si2^iv	121.1 (8)
O4ⁱⁱⁱ—Ba—O7	54.6 (3)	Ti—O2—Si2^iv	130.4 (11)
O4^xii—Ba—O6^xii	10.1 (4)	Si1—O3—Si2	158.6 (12)
O4^xii—Ba—O7	70.3 (3)	Ba^vi—O4—Ba^ix	102.7 (3)
O6^xii—Ba—O7	80.1 (4)	Ba^vi—O4—Ti	94.4 (10)
Ba^vi—Ti—Ba^ix	83.08 (7)	Ba^xiv—O4—Ti	79.3 (10)
Ba^vi—Ti—O1	138.5 (6)	Si1—O5—Si2^xi	153.1 (12)
Ba^vi—Ti—O2	50.6 (5)	Ba^xiv—O6—Ti^xv	17.2 (8)
Ba^vi—Ti—O4	58.3 (9)	Ba^xiv—O6—Si1	65.7 (7)
Ba^vi—Ti—O6^xiii	160.1 (6)	Ti^xv—O6—Si1	62.2 (5)
Ba^vi—Ti—O7^vi	58.7 (4)	Ba—O7—Tiⁱⁱⁱ	88.3 (4)
Ba^xiv—Ti—O1	31.3 (6)	Ba—O7—Si1	119.2 (6)
Ba^xiv—Ti—O2	151.6 (5)	Tiⁱⁱⁱ—O7—Si1	149.6 (9)
Ba^xiv—Ti—O4	94.7 (9)

Symmetry codes: (i) −x, −y+1, −z+1; (ii) x−1, y, z; (iii) −x+1/2, y+1/2, −z+1/2; (iv) −x+1, −y, −z+1; (v) x−1/2, −y+1/2, z+1/2; (vi) −x+1/2, y−1/2, −z+1/2; (vii) x−1/2, −y+1/2, z−1/2; (viii) x+1, y, z; (ix) x+1/2, −y+1/2, z−1/2; (x) x+1/2, −y+1/2, z+1/2; (xi) −x+1, −y+1, −z+1; (xii) x+1/2, −y+3/2, z+3/2; (xiii) x+3/2, −y+3/2, z+3/2; (xiv) x+3/2, −y+3/2, z+1/2; (xv) x+1/2, −y+3/2, z+1/2.

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