Structure of and electron density in RbTiOAsO4 at 9.6 K

Almgren, J.; Streltsov, V.A.; Sobolev, A.N.; Figgis, B.N.; Albertsson, J.

doi:10.1107/S010876819900395X

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Structure of and electron density in RbTiOAsO₄ at 9.6 K

J. Almgren, V. A. Streltsov, A. N. Sobolev, B. N. Figgis and J. Albertsson

Structure factors for rubidium titanyl arsenate, RbTiOAsO₄, were measured with Mo Kα radiation (λ = 0.71069 Å) at 9.6 and 295 K. The data show that there is no phase transition between room temperature and 9.6 K. The space group is Pna2₁. Unit-cell parameters are a = 13.218 (1), b = 6.6500 (9) and c = 10.761 (1) Å at 9.6 K, and a = 13.261 (2), b = 6.6791 (8) and c = 10.769 (1) Å at 295 K. As the temperature was lowered from 295 to 9.6 K the Rb atoms moved along the c axis in the direction of the polarization vector, while no significant change was noted for the Ti–O–As network. Strong accumulation and polarization of the difference electron density (Δρ) in exceptionally short covalent Ti—O bonds alternates with the depleted density in long Ti—O bonds. The Δρ near the Ti atoms is polarized and aligned in the negative c direction in accordance with the ferroelectric properties of this material. However, the electron density near the Rb atoms is depleted in this direction and the excess Δρ is moved further away from the nuclei along the c vector.

Keywords: Rubidium titanyl arsenate; Electron density distributions; Low-temperature diffractometry; Ferroelectrics.

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Supporting information

	Crystallographic Information File (CIF) Contains datablocks LowT, RoomT, publ
	Structure factor file (CIF format) Contains datablock LowT
	Structure factor file (CIF format) Contains datablock RoomT

Computing details top

For both compounds, data reduction: Xtal DIFDAT ADDREF ABSORB SORTRF; program(s) used to refine structure: Xtal CRYLSQ; molecular graphics: Xtal; software used to prepare material for publication: Xtal CIFIO.

Figures top

(LowT) top

Crystal data top

RbTiOAsO₄	D_x = 4.048 Mg m⁻³
M_r = 288.27	Mo Kα radiation, λ = 0.71069 Å
Orthorhombic, Pna2₁	Cell parameters from 20 reflections
Hall symbol: P 2c -2n	θ = 2.6–21.2°
a = 13.218 (1) Å	µ = 18.90 mm⁻¹
b = 6.6500 (9) Å	T = 10 K
c = 10.761 (1) Å	KTP morphology, colourless
V = 945.89 (17) Å³	0.58 × 0.54 × 0.36 mm
Z = 8

Data collection top

Huber 512 diffractometer	R_int = 0.022
profile data from ω/2θ scans	θ_max = 50.1°, θ_min = 3.1°
Absorption correction: analytical Alcock (1974)	h = −15→28
T_min = 0.008, T_max = 0.066	k = −7→14
15878 measured reflections	l = −21→22
5090 independent reflections	3 standard reflections every 100 reflections
5020 reflections with refl observed if F > 2 σ(F )	intensity decay: none

Refinement top

Refinement on F	(Δ/σ)_max = 0.385-03
Least-squares matrix: full	Δρ_max = 1.53 e Å⁻³
R[F² > 2σ(F²)] = 0.032	Δρ_min = −1.84 e Å⁻³
wR(F²) = 0.026	Extinction correction: Zachariasen (1968), Eq22 p292 "Cryst. Comp." Munksgaard 1970
S = 4.60	Extinction coefficient: 7381 (91)
5006 reflections	Absolute structure: Flack XABS refined
146 parameters	Absolute structure parameter: 0.546 (6)
1/σ²

Crystal data top

RbTiOAsO₄	V = 945.89 (17) Å³
M_r = 288.27	Z = 8
Orthorhombic, Pna2₁	Mo Kα radiation
a = 13.218 (1) Å	µ = 18.90 mm⁻¹
b = 6.6500 (9) Å	T = 10 K
c = 10.761 (1) Å	0.58 × 0.54 × 0.36 mm

Data collection top

Huber 512 diffractometer	5020 reflections with refl observed if F > 2 σ(F )
Absorption correction: analytical Alcock (1974)	R_int = 0.022
T_min = 0.008, T_max = 0.066	3 standard reflections every 100 reflections
15878 measured reflections	intensity decay: none
5090 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	Δρ_max = 1.53 e Å⁻³
wR(F²) = 0.026	Δρ_min = −1.84 e Å⁻³
S = 4.60	Absolute structure: Flack XABS refined
5006 reflections	Absolute structure parameter: 0.546 (6)
146 parameters

Special details top

Refinement. Sfls F σ weight full matrix

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

	x	y	z	U_iso*/U_eq
Rb1	0.38187 (2)	0.78084 (4)	0.68708 (6)	0.00324 (11)
Rb2	0.10896 (2)	0.69237 (4)	0.93924 (6)	0.00295 (10)
Ti1	0.37402 (4)	0.50487 (9)	1.00918 (8)	0.00226 (17)
Ti2	0.24844 (4)	0.27027 (8)	0.75921 (8)	0.00213 (17)
As1	0.49955 (3)	0.32869 (4)	0.75244 (6)	0.00165 (10)
As2	0.18019 (2)	0.50527 (6)	0.49791 (6)	0.00173 (10)
O1	0.4880 (2)	0.4908 (4)	0.8669 (2)	0.0043 (9)
O2	0.5100 (2)	0.4617 (4)	0.6181 (2)	0.0040 (9)
O3	0.39501 (18)	0.1874 (4)	0.7305 (2)	0.0040 (8)
O4	0.59976 (18)	0.1752 (4)	0.7710 (2)	0.0042 (9)
O11	0.2820 (2)	0.4527 (4)	0.8681 (2)	0.0044 (9)
O12	0.2176 (2)	0.0556 (4)	0.6185 (2)	0.0041 (9)
O5	0.1098 (2)	0.3029 (4)	0.4616 (2)	0.0039 (9)
O6	0.1068 (2)	0.7045 (4)	0.5278 (2)	0.0047 (9)
O7	0.2588 (2)	0.5443 (4)	0.3744 (2)	0.0040 (9)
O8	0.2582 (2)	0.4585 (4)	0.6171 (8)	0.0042 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Rb1	0.00387 (10)	0.00235 (10)	0.00349 (12)	0.00030 (9)	−0.00057 (10)	−0.00031 (10)
Rb2	0.00258 (9)	0.00295 (9)	0.00331 (12)	0.00030 (9)	−0.00013 (10)	−0.00017 (10)
Ti1	0.00241 (14)	0.00253 (16)	0.0018 (2)	0.00007 (18)	−0.00010 (16)	−0.00025 (17)
Ti2	0.00236 (14)	0.00239 (17)	0.0016 (2)	−0.00005 (16)	−0.00020 (15)	0.00006 (17)
As1	0.00177 (9)	0.00188 (9)	0.00130 (11)	0.00003 (11)	0.00008 (9)	0.00011 (11)
As2	0.00210 (9)	0.00172 (10)	0.00136 (11)	−0.00005 (11)	0.00000 (11)	0.00018 (10)
O1	0.0047 (8)	0.0048 (9)	0.0033 (10)	−0.0015 (8)	0.0013 (7)	−0.0012 (8)
O2	0.0046 (9)	0.0051 (9)	0.0024 (10)	0.0009 (8)	0.0016 (7)	0.0009 (7)
O3	0.0025 (7)	0.0044 (8)	0.0052 (10)	−0.0009 (7)	−0.0006 (7)	0.0010 (8)
O4	0.0032 (8)	0.0047 (8)	0.0045 (11)	0.0011 (7)	−0.0001 (7)	−0.0007 (8)
O11	0.0044 (9)	0.0048 (9)	0.0040 (11)	0.0004 (8)	−0.0008 (7)	−0.0007 (8)
O12	0.0035 (8)	0.0046 (9)	0.0041 (11)	0.0001 (8)	−0.0002 (7)	−0.0012 (8)
O5	0.0053 (8)	0.0028 (8)	0.0037 (10)	−0.0012 (8)	−0.0002 (7)	−0.0002 (7)
O6	0.0057 (8)	0.0034 (8)	0.0052 (10)	0.0014 (8)	0.0013 (8)	−0.0002 (7)
O7	0.0043 (9)	0.0048 (9)	0.0030 (11)	0.0000 (8)	0.0012 (7)	0.0010 (8)
O8	0.0051 (9)	0.0050 (9)	0.0025 (10)	−0.0009 (8)	−0.0014 (7)	0.0013 (7)

Geometric parameters (Å, º) top

Rb1—Rb2	4.5521 (7)	Rb2—O5^vii	2.902 (3)
Rb1—As1	3.4577 (6)	Ti1—O1	2.150 (3)
Rb1—O1	3.071 (3)	Ti1—O11	1.977 (3)
Rb1—O2	2.815 (3)	Ti1—O5ⁱⁱ	2.058 (3)
Rb1—O3ⁱ	2.749 (3)	Ti1—O2^viii	1.942 (3)
Rb1—O11	3.209 (3)	Ti1—O6^ix	2.023 (3)
Rb1—O12ⁱ	2.932 (3)	Ti1—O12ⁱⁱ	1.722 (3)
Rb1—O5ⁱⁱ	2.959 (3)	Ti2ⁱ—O3ⁱ	2.038 (2)
Rb1—O6ⁱⁱⁱ	3.434 (3)	Ti2ⁱ—O12ⁱ	2.121 (3)
Rb1—O7ⁱⁱ	3.254 (3)	Ti2ⁱ—O7ⁱⁱ	1.950 (3)
Rb1—O8	2.799 (3)	Ti2ⁱ—O4^vi	2.002 (2)
Rb1—Rb2^iv	3.8232 (8)	Ti2ⁱ—O11ⁱ	1.744 (3)
Rb1—Rb2ⁱⁱⁱ	4.0503 (7)	Ti2ⁱ—O8ⁱ	1.980 (7)
Rb2—As2ⁱⁱ	3.5350 (5)	As1—O1	1.644 (3)
Rb2—O4^v	3.044 (3)	As1—O2	1.701 (3)
Rb2—O11	2.891 (3)	As1—O3	1.688 (2)
Rb2—O7ⁱⁱ	3.004 (3)	As1—O4	1.684 (2)
Rb2—O3ⁱⁱ	3.135 (3)	As2ⁱⁱ—O5ⁱⁱ	1.682 (3)
Rb2—O12ⁱⁱ	3.131 (3)	As2ⁱⁱ—O7ⁱⁱ	1.706 (3)
Rb2—O2ⁱⁱ	3.063 (3)	As2ⁱⁱ—O6ⁱⁱ	1.673 (3)
Rb2—O8ⁱⁱ	3.144 (5)	As2ⁱⁱ—O8ⁱⁱ	1.675 (6)
Rb2—O1^vi	2.757 (3)

Rb2—Rb1—As1	97.056 (15)	Rb1^ix—Rb2—O2ⁱⁱ	89.80 (5)
Rb2—Rb1—O1	84.57 (5)	Rb1^ix—Rb2—O8ⁱⁱ	87.73 (11)
Rb2—Rb1—O2	122.45 (6)	Rb1^ix—Rb2—Rb1^vi	121.488 (11)
Rb2—Rb1—O3ⁱ	94.35 (5)	Rb1^ix—Rb2—O1^vi	139.68 (6)
Rb2—Rb1—O11	39.13 (5)	Rb1^ix—Rb2—O5^vii	88.95 (5)
Rb2—Rb1—O12ⁱ	69.13 (5)	O3ⁱⁱ—Rb2—O12ⁱⁱ	52.64 (7)
Rb2—Rb1—O5ⁱⁱ	56.00 (5)	O3ⁱⁱ—Rb2—O2ⁱⁱ	50.91 (7)
Rb2—Rb1—O6ⁱⁱⁱ	170.93 (5)	O3ⁱⁱ—Rb2—O8ⁱⁱ	53.59 (13)
Rb2—Rb1—O7ⁱⁱ	41.20 (5)	O3ⁱⁱ—Rb2—Rb1^vi	131.14 (5)
Rb2—Rb1—O8	66.32 (13)	O3ⁱⁱ—Rb2—O1^vi	106.30 (7)
Rb2—Rb1—Rb2^iv	122.241 (11)	O3ⁱⁱ—Rb2—O5^vii	84.30 (7)
Rb2—Rb1—Rb2ⁱⁱⁱ	101.164 (18)	O12ⁱⁱ—Rb2—O2ⁱⁱ	99.13 (7)
As1—Rb1—O1	28.38 (5)	O12ⁱⁱ—Rb2—O8ⁱⁱ	51.64 (8)
As1—Rb1—O2	29.23 (6)	O12ⁱⁱ—Rb2—Rb1^vi	165.49 (5)
As1—Rb1—O3ⁱ	142.39 (5)	O12ⁱⁱ—Rb2—O1^vi	145.14 (8)
As1—Rb1—O11	58.02 (5)	O12ⁱⁱ—Rb2—O5^vii	132.98 (7)
As1—Rb1—O12ⁱ	157.85 (5)	O2ⁱⁱ—Rb2—O8ⁱⁱ	64.85 (9)
As1—Rb1—O5ⁱⁱ	79.83 (5)	O2ⁱⁱ—Rb2—Rb1^vi	90.84 (5)
As1—Rb1—O6ⁱⁱⁱ	74.73 (4)	O2ⁱⁱ—Rb2—O1^vi	55.46 (8)
As1—Rb1—O7ⁱⁱ	126.81 (5)	O2ⁱⁱ—Rb2—O5^vii	55.26 (7)
As1—Rb1—O8	69.61 (7)	O8ⁱⁱ—Rb2—Rb1^vi	142.87 (6)
As1—Rb1—Rb2^iv	138.60 (2)	O8ⁱⁱ—Rb2—O1^vi	93.77 (8)
As1—Rb1—Rb2ⁱⁱⁱ	64.441 (13)	O8ⁱⁱ—Rb2—O5^vii	120.02 (9)
O1—Rb1—O2	54.40 (7)	Rb1^vi—Rb2—O1^vi	49.27 (6)
O1—Rb1—O3ⁱ	118.79 (8)	Rb1^vi—Rb2—O5^vii	46.88 (5)
O1—Rb1—O11	51.58 (7)	O1^vi—Rb2—O5^vii	55.76 (7)
O1—Rb1—O12ⁱ	152.65 (7)	O1—Ti1—O11	82.92 (11)
O1—Rb1—O5ⁱⁱ	52.08 (7)	O1—Ti1—O5ⁱⁱ	77.99 (10)
O1—Rb1—O6ⁱⁱⁱ	86.36 (7)	O1—Ti1—O2^viii	83.19 (11)
O1—Rb1—O7ⁱⁱ	102.05 (7)	O1—Ti1—O6^ix	86.56 (11)
O1—Rb1—O8	87.45 (12)	O1—Ti1—O12ⁱⁱ	171.11 (12)
O1—Rb1—Rb2^iv	150.99 (5)	O11—Ti1—O5ⁱⁱ	92.39 (11)
O1—Rb1—Rb2ⁱⁱⁱ	42.86 (5)	O11—Ti1—O2^viii	165.79 (12)
O2—Rb1—O3ⁱ	138.44 (7)	O11—Ti1—O6^ix	88.84 (11)
O2—Rb1—O11	83.97 (7)	O11—Ti1—O12ⁱⁱ	97.25 (12)
O2—Rb1—O12ⁱ	148.09 (8)	O5ⁱⁱ—Ti1—O2^viii	87.60 (11)
O2—Rb1—O5ⁱⁱ	106.16 (7)	O5ⁱⁱ—Ti1—O6^ix	164.22 (11)
O2—Rb1—O6ⁱⁱⁱ	50.85 (7)	O5ⁱⁱ—Ti1—O12ⁱⁱ	93.12 (12)
O2—Rb1—O7ⁱⁱ	155.93 (7)	O2^viii—Ti1—O6^ix	87.39 (11)
O2—Rb1—O8	72.73 (8)	O2^viii—Ti1—O12ⁱⁱ	96.93 (13)
O2—Rb1—Rb2^iv	109.67 (6)	O6^ix—Ti1—O12ⁱⁱ	102.33 (12)
O2—Rb1—Rb2ⁱⁱⁱ	76.35 (5)	O3ⁱ—Ti2ⁱ—O12ⁱ	83.82 (10)
O3ⁱ—Rb1—O11	126.27 (7)	O3ⁱ—Ti2ⁱ—O7ⁱⁱ	86.23 (11)
O3ⁱ—Rb1—O12ⁱ	58.45 (7)	O3ⁱ—Ti2ⁱ—O4^vi	172.59 (11)
O3ⁱ—Rb1—O5ⁱⁱ	77.25 (7)	O3ⁱ—Ti2ⁱ—O11ⁱ	92.77 (12)
O3ⁱ—Rb1—O6ⁱⁱⁱ	90.13 (7)	O3ⁱ—Ti2ⁱ—O8ⁱ	89.56 (11)
O3ⁱ—Rb1—O7ⁱⁱ	53.22 (7)	O12ⁱ—Ti2ⁱ—O7ⁱⁱ	85.75 (11)
O3ⁱ—Rb1—O8	146.69 (8)	O12ⁱ—Ti2ⁱ—O4^vi	88.78 (10)
O3ⁱ—Rb1—Rb2^iv	54.03 (6)	O12ⁱ—Ti2ⁱ—O11ⁱ	175.50 (12)
O3ⁱ—Rb1—Rb2ⁱⁱⁱ	78.23 (5)	O12ⁱ—Ti2ⁱ—O8ⁱ	83.50 (18)
O11—Rb1—O12ⁱ	105.77 (7)	O7ⁱⁱ—Ti2ⁱ—O4^vi	92.95 (11)
O11—Rb1—O5ⁱⁱ	56.17 (7)	O7ⁱⁱ—Ti2ⁱ—O11ⁱ	96.97 (12)
O11—Rb1—O6ⁱⁱⁱ	132.73 (7)	O7ⁱⁱ—Ti2ⁱ—O8ⁱ	168.82 (18)
O11—Rb1—O7ⁱⁱ	75.83 (7)	O4^vi—Ti2ⁱ—O11ⁱ	94.64 (12)
O11—Rb1—O8	53.28 (17)	O4^vi—Ti2ⁱ—O8ⁱ	89.89 (11)
O11—Rb1—Rb2^iv	157.39 (5)	O11ⁱ—Ti2ⁱ—O8ⁱ	93.57 (18)
O11—Rb1—Rb2ⁱⁱⁱ	85.89 (5)	Rb1—As1—O1	62.64 (9)
O12ⁱ—Rb1—O5ⁱⁱ	104.35 (7)	Rb1—As1—O2	53.94 (9)
O12ⁱ—Rb1—O6ⁱⁱⁱ	119.87 (7)	Rb1—As1—O3	95.02 (8)
O12ⁱ—Rb1—O7ⁱⁱ	52.95 (7)	Rb1—As1—O4	154.83 (9)
O12ⁱ—Rb1—O8	88.68 (9)	O1—As1—O2	107.67 (13)
O12ⁱ—Rb1—Rb2^iv	53.26 (5)	O1—As1—O3	113.21 (13)
O12ⁱ—Rb1—Rb2ⁱⁱⁱ	133.63 (5)	O1—As1—O4	112.43 (13)
O5ⁱⁱ—Rb1—O6ⁱⁱⁱ	117.69 (7)	O2—As1—O3	103.72 (13)
O5ⁱⁱ—Rb1—O7ⁱⁱ	51.40 (7)	O2—As1—O4	110.62 (13)
O5ⁱⁱ—Rb1—O8	109.14 (17)	O3—As1—O4	108.85 (12)
O5ⁱⁱ—Rb1—Rb2^iv	131.27 (5)	Rb2—As2ⁱⁱ—O5ⁱⁱ	85.60 (9)
O5ⁱⁱ—Rb1—Rb2ⁱⁱⁱ	45.71 (5)	Rb2—As2ⁱⁱ—O7ⁱⁱ	58.04 (9)
O6ⁱⁱⁱ—Rb1—O7ⁱⁱ	142.06 (6)	Rb2—As2ⁱⁱ—O6ⁱⁱ	163.21 (9)
O6ⁱⁱⁱ—Rb1—O8	113.17 (12)	Rb2—As2ⁱⁱ—O8ⁱⁱ	62.77 (18)
O6ⁱⁱⁱ—Rb1—Rb2^iv	66.68 (4)	O5ⁱⁱ—As2ⁱⁱ—O7ⁱⁱ	106.09 (13)
O6ⁱⁱⁱ—Rb1—Rb2ⁱⁱⁱ	72.02 (5)	O5ⁱⁱ—As2ⁱⁱ—O6ⁱⁱ	110.98 (12)
O7ⁱⁱ—Rb1—O8	104.19 (12)	O5ⁱⁱ—As2ⁱⁱ—O8ⁱⁱ	111.70 (13)
O7ⁱⁱ—Rb1—Rb2^iv	93.72 (5)	O7ⁱⁱ—As2ⁱⁱ—O6ⁱⁱ	112.46 (13)
O7ⁱⁱ—Rb1—Rb2ⁱⁱⁱ	89.12 (5)	O7ⁱⁱ—As2ⁱⁱ—O8ⁱⁱ	104.5 (2)
O8—Rb1—Rb2^iv	112.28 (15)	O6ⁱⁱ—As2ⁱⁱ—O8ⁱⁱ	110.87 (19)
O8—Rb1—Rb2ⁱⁱⁱ	130.30 (12)	Rb1—O1—Ti1	95.80 (9)
Rb2^iv—Rb1—Rb2ⁱⁱⁱ	114.353 (12)	Rb1—O1—As1	88.98 (11)
Rb1—Rb2—As2ⁱⁱ	53.530 (14)	Rb1—O1—Rb2ⁱⁱⁱ	87.88 (7)
Rb1—Rb2—O4^v	77.34 (5)	Ti1—O1—As1	128.82 (15)
Rb1—Rb2—O11	44.47 (5)	Ti1—O1—Rb2ⁱⁱⁱ	99.91 (10)
Rb1—Rb2—O7ⁱⁱ	45.54 (5)	As1—O1—Rb2ⁱⁱⁱ	131.23 (14)
Rb1—Rb2—Rb1^ix	118.896 (11)	Rb1—O2—As1	96.83 (11)
Rb1—Rb2—O3ⁱⁱ	127.64 (4)	Rb1—O2—Ti1^x	123.21 (12)
Rb1—Rb2—O12ⁱⁱ	79.90 (5)	Rb1—O2—Rb2^xi	107.32 (8)
Rb1—Rb2—O2ⁱⁱ	134.89 (5)	As1—O2—Ti1^x	129.53 (15)
Rb1—Rb2—O8ⁱⁱ	81.23 (11)	As1—O2—Rb2^xi	100.86 (11)
Rb1—Rb2—Rb1^vi	100.501 (18)	Ti1^x—O2—Rb2^xi	95.34 (10)
Rb1—Rb2—O1^vi	101.09 (6)	Rb1—O3ⁱ—Ti2ⁱ	103.40 (9)
Rb1—Rb2—O5^vii	146.89 (5)	Rb1—O3ⁱ—As1ⁱ	128.55 (12)
As2ⁱⁱ—Rb2—O4^v	127.61 (5)	Rb1—O3ⁱ—Rb2^iv	80.76 (7)
As2ⁱⁱ—Rb2—O11	75.41 (6)	Ti2ⁱ—O3ⁱ—As1ⁱ	127.34 (14)
As2ⁱⁱ—Rb2—O7ⁱⁱ	28.82 (5)	Ti2ⁱ—O3ⁱ—Rb2^iv	97.63 (9)
As2ⁱⁱ—Rb2—Rb1^ix	105.768 (18)	As1ⁱ—O3ⁱ—Rb2^iv	98.49 (11)
As2ⁱⁱ—Rb2—O3ⁱⁱ	80.84 (5)	Rb2—O4^v—Ti2	98.27 (9)
As2ⁱⁱ—Rb2—O12ⁱⁱ	58.92 (5)	Rb2—O4^v—As1^v	126.05 (12)
As2ⁱⁱ—Rb2—O2ⁱⁱ	87.04 (5)	Ti2—O4^v—As1^v	130.89 (14)
As2ⁱⁱ—Rb2—O8ⁱⁱ	28.28 (12)	Rb1—O11—Rb2	96.40 (8)
As2ⁱⁱ—Rb2—Rb1^vi	132.694 (18)	Rb1—O11—Ti1	95.37 (10)
As2ⁱⁱ—Rb2—O1^vi	93.31 (6)	Rb1—O11—Ti2	99.79 (11)
As2ⁱⁱ—Rb2—O5^vii	139.86 (5)	Rb2—O11—Ti1	100.75 (10)
O4^v—Rb2—O11	55.34 (7)	Rb2—O11—Ti2	111.13 (12)
O4^v—Rb2—O7ⁱⁱ	120.72 (7)	Ti1—O11—Ti2	142.63 (16)
O4^v—Rb2—Rb1^ix	80.88 (5)	Rb1—O12ⁱ—Ti2ⁱ	95.60 (9)
O4^v—Rb2—O3ⁱⁱ	125.84 (7)	Rb1—O12ⁱ—Rb2^iv	78.11 (6)
O4^v—Rb2—O12ⁱⁱ	99.35 (7)	Rb1—O12ⁱ—Ti1^iv	124.81 (13)
O4^v—Rb2—O2ⁱⁱ	145.34 (7)	Ti2ⁱ—O12ⁱ—Rb2^iv	95.95 (9)
O4^v—Rb2—O8ⁱⁱ	146.78 (7)	Ti2ⁱ—O12ⁱ—Ti1^iv	139.01 (15)
O4^v—Rb2—Rb1^vi	66.87 (5)	Rb2^iv—O12ⁱ—Ti1^iv	98.69 (11)
O4^v—Rb2—O1^vi	114.99 (7)	Rb1—O5ⁱⁱ—Ti1	101.35 (9)
O4^v—Rb2—O5^vii	91.04 (7)	Rb1—O5ⁱⁱ—As2ⁱⁱ	104.55 (11)
O11—Rb2—O7ⁱⁱ	84.70 (7)	Rb1—O5ⁱⁱ—Rb2ⁱⁱⁱ	87.41 (7)
O11—Rb2—Rb1^ix	76.42 (5)	Ti1—O5ⁱⁱ—As2ⁱⁱ	130.94 (14)
O11—Rb2—O3ⁱⁱ	105.80 (7)	Ti1—O5ⁱⁱ—Rb2ⁱⁱⁱ	97.72 (9)
O11—Rb2—O12ⁱⁱ	54.82 (7)	As2ⁱⁱ—O5ⁱⁱ—Rb2ⁱⁱⁱ	124.16 (12)
O11—Rb2—O2ⁱⁱ	153.49 (7)	Rb1—O6ⁱⁱⁱ—Ti1^x	97.46 (9)
O11—Rb2—O8ⁱⁱ	91.71 (8)	Rb1—O6ⁱⁱⁱ—As2ⁱⁱⁱ	128.34 (12)
O11—Rb2—Rb1^vi	115.66 (6)	Ti1^x—O6ⁱⁱⁱ—As2ⁱⁱⁱ	133.65 (15)
O11—Rb2—O1^vi	143.63 (8)	Rb1—O7ⁱⁱ—Rb2	93.26 (7)
O11—Rb2—O5^vii	144.71 (7)	Rb1—O7ⁱⁱ—Ti2ⁱ	89.60 (9)
O7ⁱⁱ—Rb2—Rb1^ix	134.53 (5)	Rb1—O7ⁱⁱ—As2ⁱⁱ	93.03 (10)
O7ⁱⁱ—Rb2—O3ⁱⁱ	104.49 (7)	Rb2—O7ⁱⁱ—Ti2ⁱ	140.92 (12)
O7ⁱⁱ—Rb2—O12ⁱⁱ	86.75 (7)	Rb2—O7ⁱⁱ—As2ⁱⁱ	93.15 (10)
O7ⁱⁱ—Rb2—O2ⁱⁱ	89.38 (7)	Ti2ⁱ—O7ⁱⁱ—As2ⁱⁱ	125.63 (15)
O7ⁱⁱ—Rb2—O8ⁱⁱ	51.50 (13)	Rb1—O8—Ti2	108.3 (3)
O7ⁱⁱ—Rb2—Rb1^vi	103.98 (5)	Rb1—O8—Rb2^xi	105.57 (11)
O7ⁱⁱ—Rb2—O1^vi	71.12 (8)	Rb1—O8—As2	115.05 (18)
O7ⁱⁱ—Rb2—O5^vii	126.22 (7)	Ti2—O8—Rb2^xi	98.65 (10)
Rb1^ix—Rb2—O3ⁱⁱ	45.21 (5)	Ti2—O8—As2	131.98 (16)
Rb1^ix—Rb2—O12ⁱⁱ	48.63 (5)	Rb2^xi—O8—As2	89.0 (3)

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

(RoomT) top

Crystal data top

RbTiOAsO₄	D_x = 4.015 Mg m⁻³
M_r = 288.27	Mo Kα radiation, λ = 0.71069 Å
Orthorhombic, Pna2₁	Cell parameters from 18 reflections
Hall symbol: P 2c -2n	θ = 7.1–17.4°
a = 13.261 (2) Å	µ = 18.74 mm⁻¹
b = 6.6791 (8) Å	T = 295 K
c = 10.769 (1) Å	KTP morphology, colourless
V = 953.8 (2) Å³	0.58 × 0.54 × 0.36 mm
Z = 8

Data collection top

Huber 512 diffractometer	R_int = 0.055
profile data from ω/2θ scans	θ_max = 50.1°, θ_min = 3.1°
Absorption correction: analytical Alcock (1974)	h = 0→28
T_min = 0.008, T_max = 0.066	k = 0→14
9854 measured reflections	l = −21→22
5125 independent reflections	3 standard reflections every 100 reflections
4852 reflections with refl observed if F > 2 σ(F )	intensity decay: none

Refinement top

Refinement on F	(Δ/σ)_max = 0.255-03
Least-squares matrix: full	Δρ_max = 3.06 e Å⁻³
R[F² > 2σ(F²)] = 0.055	Δρ_min = −2.84 e Å⁻³
wR(F²) = 0.043	Extinction correction: Zachariasen 1968), Eq22 p292 "Cryst. Comp." Munksgaard 1970
S = 4.76	Extinction coefficient: 17128 (240)
4796 reflections	Absolute structure: Flack XABS refined
146 parameters	Absolute structure parameter: 0.59 (1)
1/σ²

Crystal data top

RbTiOAsO₄	V = 953.8 (2) Å³
M_r = 288.27	Z = 8
Orthorhombic, Pna2₁	Mo Kα radiation
a = 13.261 (2) Å	µ = 18.74 mm⁻¹
b = 6.6791 (8) Å	T = 295 K
c = 10.769 (1) Å	0.58 × 0.54 × 0.36 mm

Data collection top

Huber 512 diffractometer	4852 reflections with refl observed if F > 2 σ(F )
Absorption correction: analytical Alcock (1974)	R_int = 0.055
T_min = 0.008, T_max = 0.066	3 standard reflections every 100 reflections
9854 measured reflections	intensity decay: none
5125 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.055	Δρ_max = 3.06 e Å⁻³
wR(F²) = 0.043	Δρ_min = −2.84 e Å⁻³
S = 4.76	Absolute structure: Flack XABS refined
4796 reflections	Absolute structure parameter: 0.59 (1)
146 parameters

Special details top

Refinement. Sfls F σ weight full matrix

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

	x	y	z	U_iso*/U_eq
Rb1	0.38304 (6)	0.78228 (10)	0.68223 (13)	0.0209 (3)
Rb2	0.10905 (5)	0.69381 (11)	0.93537 (13)	0.0172 (3)
Ti1	0.37370 (7)	0.50486 (18)	1.00974 (15)	0.0060 (3)
Ti2	0.24874 (9)	0.26985 (15)	0.75971 (14)	0.0057 (3)
As1	0.49964 (5)	0.32826 (8)	0.75318 (12)	0.00538 (17)
As2	0.17988 (4)	0.50516 (11)	0.49892 (12)	0.00579 (18)
O1	0.4874 (4)	0.4888 (9)	0.8681 (5)	0.011 (2)
O2	0.5102 (4)	0.4614 (9)	0.6189 (5)	0.010 (2)
O3	0.3952 (4)	0.1881 (7)	0.7306 (5)	0.011 (2)
O4	0.6002 (3)	0.1776 (7)	0.7725 (5)	0.0095 (19)
O11	0.2818 (4)	0.4522 (8)	0.8683 (5)	0.009 (2)
O12	0.2177 (4)	0.0558 (8)	0.6181 (5)	0.009 (2)
O5	0.1099 (4)	0.3031 (7)	0.4607 (5)	0.0100 (18)
O6	0.1072 (4)	0.7043 (7)	0.5308 (5)	0.013 (2)
O7	0.2580 (4)	0.5444 (8)	0.3746 (4)	0.010 (2)
O8	0.2578 (4)	0.4584 (8)	0.6172 (15)	0.011 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Rb1	0.0226 (3)	0.0100 (3)	0.0299 (4)	0.0030 (3)	−0.0076 (3)	−0.0031 (3)
Rb2	0.0119 (2)	0.0155 (3)	0.0243 (4)	0.0035 (3)	−0.0013 (3)	−0.0020 (3)
Ti1	0.0059 (2)	0.0066 (3)	0.0054 (4)	0.0001 (4)	0.0002 (3)	−0.0008 (3)
Ti2	0.0059 (2)	0.0069 (3)	0.0044 (3)	−0.0002 (3)	−0.0005 (3)	−0.0001 (4)
As1	0.00448 (14)	0.00624 (16)	0.00542 (19)	−0.0000 (2)	0.00063 (16)	−0.0002 (2)
As2	0.00695 (16)	0.00517 (18)	0.0053 (2)	−0.0003 (2)	−0.0001 (2)	0.00068 (18)
O1	0.0104 (18)	0.013 (2)	0.010 (2)	−0.0024 (18)	0.0030 (15)	−0.0045 (18)
O2	0.011 (2)	0.014 (2)	0.0062 (19)	0.0028 (18)	0.0035 (15)	0.0042 (15)
O3	0.0061 (15)	0.0089 (17)	0.019 (3)	−0.0012 (16)	0.0000 (16)	−0.0002 (18)
O4	0.0038 (15)	0.0083 (16)	0.016 (3)	0.0008 (15)	−0.0011 (15)	0.0009 (17)
O11	0.0083 (18)	0.012 (2)	0.007 (2)	0.0010 (17)	−0.0025 (14)	−0.0019 (16)
O12	0.010 (2)	0.0106 (19)	0.006 (2)	0.0003 (17)	−0.0010 (14)	−0.0013 (15)
O5	0.0127 (18)	0.0085 (16)	0.009 (2)	−0.0023 (18)	−0.0034 (16)	−0.0005 (15)
O6	0.0116 (18)	0.0067 (16)	0.021 (3)	0.0029 (18)	0.0041 (18)	0.0015 (17)
O7	0.013 (2)	0.012 (2)	0.004 (2)	0.002 (2)	0.0022 (15)	0.0039 (15)
O8	0.013 (2)	0.014 (2)	0.008 (2)	−0.005 (2)	−0.0047 (16)	0.0027 (16)

Geometric parameters (Å, º) top

Rb1—Rb2	4.5807 (15)	Rb2—O5^vii	2.916 (5)
Rb1—As1	3.4886 (10)	Ti1—O1	2.147 (6)
Rb1—O1	3.125 (6)	Ti1—O11	1.982 (5)
Rb1—O2	2.811 (6)	Ti1—O5ⁱⁱ	2.072 (5)
Rb1—O3ⁱ	2.765 (5)	Ti1—O2^viii	1.950 (5)
Rb1—O11	3.268 (5)	Ti1—O6^ix	2.036 (5)
Rb1—O12ⁱ	2.937 (6)	Ti1—O12ⁱⁱ	1.716 (5)
Rb1—O5ⁱⁱ	3.004 (5)	Ti2ⁱ—O3ⁱ	2.042 (5)
Rb1—O6ⁱⁱⁱ	3.392 (6)	Ti2ⁱ—O12ⁱ	2.131 (5)
Rb1—O7ⁱⁱ	3.294 (5)	Ti2ⁱ—O7ⁱⁱ	1.950 (5)
Rb1—O8	2.816 (7)	Ti2ⁱ—O4^vi	2.005 (5)
Rb1—Rb2^iv	3.8255 (16)	Ti2ⁱ—O11ⁱ	1.745 (5)
Rb1—Rb2ⁱⁱⁱ	4.0545 (16)	Ti2ⁱ—O8ⁱ	1.989 (13)
Rb2—As2ⁱⁱ	3.5535 (10)	As1—O1	1.646 (6)
Rb2—O4^v	3.040 (5)	As1—O2	1.703 (5)
Rb2—O11	2.893 (5)	As1—O3	1.689 (5)
Rb2—O7ⁱⁱ	3.004 (6)	As1—O4	1.684 (5)
Rb2—O3ⁱⁱ	3.181 (6)	As2ⁱⁱ—O5ⁱⁱ	1.689 (5)
Rb2—O12ⁱⁱ	3.163 (5)	As2ⁱⁱ—O7ⁱⁱ	1.713 (5)
Rb2—O2ⁱⁱ	3.099 (6)	As2ⁱⁱ—O6ⁱⁱ	1.678 (5)
Rb2—O8ⁱⁱ	3.174 (11)	As2ⁱⁱ—O8ⁱⁱ	1.669 (13)
Rb2—O1^vi	2.761 (6)

Rb2—Rb1—As1	96.27 (3)	Rb1^ix—Rb2—O2ⁱⁱ	89.15 (11)
Rb2—Rb1—O1	83.64 (11)	Rb1^ix—Rb2—O8ⁱⁱ	87.5 (2)
Rb2—Rb1—O2	121.46 (11)	Rb1^ix—Rb2—Rb1^vi	121.05 (3)
Rb2—Rb1—O3ⁱ	93.47 (11)	Rb1^ix—Rb2—O1^vi	138.60 (12)
Rb2—Rb1—O11	38.93 (10)	Rb1^ix—Rb2—O5^vii	88.12 (10)
Rb2—Rb1—O12ⁱ	68.15 (10)	O3ⁱⁱ—Rb2—O12ⁱⁱ	52.21 (13)
Rb2—Rb1—O5ⁱⁱ	55.71 (10)	O3ⁱⁱ—Rb2—O2ⁱⁱ	50.23 (13)
Rb2—Rb1—O6ⁱⁱⁱ	169.98 (10)	O3ⁱⁱ—Rb2—O8ⁱⁱ	53.1 (3)
Rb2—Rb1—O7ⁱⁱ	40.90 (10)	O3ⁱⁱ—Rb2—Rb1^vi	131.27 (9)
Rb2—Rb1—O8	65.2 (3)	O3ⁱⁱ—Rb2—O1^vi	105.14 (14)
Rb2—Rb1—Rb2^iv	121.87 (3)	O3ⁱⁱ—Rb2—O5^vii	83.62 (13)
Rb2—Rb1—Rb2ⁱⁱⁱ	101.03 (4)	O12ⁱⁱ—Rb2—O2ⁱⁱ	98.17 (14)
As1—Rb1—O1	28.13 (10)	O12ⁱⁱ—Rb2—O8ⁱⁱ	51.27 (16)
As1—Rb1—O2	28.90 (11)	O12ⁱⁱ—Rb2—Rb1^vi	165.21 (10)
As1—Rb1—O3ⁱ	141.72 (11)	O12ⁱⁱ—Rb2—O1^vi	144.25 (15)
As1—Rb1—O11	57.42 (10)	O12ⁱⁱ—Rb2—O5^vii	131.84 (14)
As1—Rb1—O12ⁱ	157.41 (11)	O2ⁱⁱ—Rb2—O8ⁱⁱ	64.49 (18)
As1—Rb1—O5ⁱⁱ	78.92 (10)	O2ⁱⁱ—Rb2—Rb1^vi	91.65 (10)
As1—Rb1—O6ⁱⁱⁱ	74.92 (9)	O2ⁱⁱ—Rb2—O1^vi	54.98 (15)
As1—Rb1—O7ⁱⁱ	125.17 (10)	O2ⁱⁱ—Rb2—O5^vii	55.11 (14)
As1—Rb1—O8	69.40 (15)	O8ⁱⁱ—Rb2—Rb1^vi	143.51 (13)
As1—Rb1—Rb2^iv	139.87 (4)	O8ⁱⁱ—Rb2—O1^vi	93.39 (17)
As1—Rb1—Rb2ⁱⁱⁱ	63.85 (3)	O8ⁱⁱ—Rb2—O5^vii	119.5 (2)
O1—Rb1—O2	53.95 (14)	Rb1^vi—Rb2—O1^vi	50.32 (12)
O1—Rb1—O3ⁱ	117.93 (16)	Rb1^vi—Rb2—O5^vii	47.68 (10)
O1—Rb1—O11	50.65 (14)	O1^vi—Rb2—O5^vii	55.77 (15)
O1—Rb1—O12ⁱ	150.65 (15)	O1—Ti1—O11	83.0 (2)
O1—Rb1—O5ⁱⁱ	51.37 (14)	O1—Ti1—O5ⁱⁱ	78.1 (2)
O1—Rb1—O6ⁱⁱⁱ	86.36 (14)	O1—Ti1—O2^viii	83.1 (2)
O1—Rb1—O7ⁱⁱ	100.49 (14)	O1—Ti1—O6^ix	86.7 (2)
O1—Rb1—O8	86.5 (3)	O1—Ti1—O12ⁱⁱ	171.3 (2)
O1—Rb1—Rb2^iv	152.10 (11)	O11—Ti1—O5ⁱⁱ	92.3 (2)
O1—Rb1—Rb2ⁱⁱⁱ	42.83 (11)	O11—Ti1—O2^viii	165.7 (2)
O2—Rb1—O3ⁱ	139.30 (16)	O11—Ti1—O6^ix	89.3 (2)
O2—Rb1—O11	83.17 (15)	O11—Ti1—O12ⁱⁱ	97.1 (2)
O2—Rb1—O12ⁱ	149.91 (15)	O5ⁱⁱ—Ti1—O2^viii	87.7 (2)
O2—Rb1—O5ⁱⁱ	105.00 (15)	O5ⁱⁱ—Ti1—O6^ix	164.4 (2)
O2—Rb1—O6ⁱⁱⁱ	51.52 (14)	O5ⁱⁱ—Ti1—O12ⁱⁱ	93.3 (2)
O2—Rb1—O7ⁱⁱ	153.94 (14)	O2^viii—Ti1—O6^ix	87.1 (2)
O2—Rb1—O8	73.01 (17)	O2^viii—Ti1—O12ⁱⁱ	97.2 (2)
O2—Rb1—Rb2^iv	111.27 (11)	O6^ix—Ti1—O12ⁱⁱ	102.0 (2)
O2—Rb1—Rb2ⁱⁱⁱ	75.50 (11)	O3ⁱ—Ti2ⁱ—O12ⁱ	84.0 (2)
O3ⁱ—Rb1—O11	124.72 (15)	O3ⁱ—Ti2ⁱ—O7ⁱⁱ	86.2 (2)
O3ⁱ—Rb1—O12ⁱ	58.53 (15)	O3ⁱ—Ti2ⁱ—O4^vi	172.6 (2)
O3ⁱ—Rb1—O5ⁱⁱ	76.38 (15)	O3ⁱ—Ti2ⁱ—O11ⁱ	92.9 (2)
O3ⁱ—Rb1—O6ⁱⁱⁱ	90.78 (14)	O3ⁱ—Ti2ⁱ—O8ⁱ	89.6 (2)
O3ⁱ—Rb1—O7ⁱⁱ	52.66 (14)	O12ⁱ—Ti2ⁱ—O7ⁱⁱ	85.8 (2)
O3ⁱ—Rb1—O8	146.55 (16)	O12ⁱ—Ti2ⁱ—O4^vi	88.7 (2)
O3ⁱ—Rb1—Rb2^iv	54.90 (12)	O12ⁱ—Ti2ⁱ—O11ⁱ	175.5 (2)
O3ⁱ—Rb1—Rb2ⁱⁱⁱ	77.97 (11)	O12ⁱ—Ti2ⁱ—O8ⁱ	83.4 (4)
O11—Rb1—O12ⁱ	104.90 (14)	O7ⁱⁱ—Ti2ⁱ—O4^vi	92.7 (2)
O11—Rb1—O5ⁱⁱ	55.37 (13)	O7ⁱⁱ—Ti2ⁱ—O11ⁱ	97.2 (2)
O11—Rb1—O6ⁱⁱⁱ	132.29 (13)	O7ⁱⁱ—Ti2ⁱ—O8ⁱ	168.8 (4)
O11—Rb1—O7ⁱⁱ	74.91 (13)	O4^vi—Ti2ⁱ—O11ⁱ	94.5 (2)
O11—Rb1—O8	52.6 (3)	O4^vi—Ti2ⁱ—O8ⁱ	90.1 (2)
O11—Rb1—Rb2^iv	157.25 (10)	O11ⁱ—Ti2ⁱ—O8ⁱ	93.4 (4)
O11—Rb1—Rb2ⁱⁱⁱ	85.30 (10)	Rb1—As1—O1	63.6 (2)
O12ⁱ—Rb1—O5ⁱⁱ	103.26 (14)	Rb1—As1—O2	52.90 (19)
O12ⁱ—Rb1—O6ⁱⁱⁱ	121.66 (14)	Rb1—As1—O3	94.98 (17)
O12ⁱ—Rb1—O7ⁱⁱ	52.65 (13)	Rb1—As1—O4	153.85 (17)
O12ⁱ—Rb1—O8	88.79 (18)	O1—As1—O2	107.9 (3)
O12ⁱ—Rb1—Rb2^iv	53.84 (10)	O1—As1—O3	112.8 (3)
O12ⁱ—Rb1—Rb2ⁱⁱⁱ	133.29 (11)	O1—As1—O4	112.0 (3)
O5ⁱⁱ—Rb1—O6ⁱⁱⁱ	116.84 (14)	O2—As1—O3	103.6 (3)
O5ⁱⁱ—Rb1—O7ⁱⁱ	50.61 (13)	O2—As1—O4	110.6 (3)
O5ⁱⁱ—Rb1—O8	107.6 (3)	O3—As1—O4	109.6 (2)
O5ⁱⁱ—Rb1—Rb2^iv	131.28 (10)	Rb2—As2ⁱⁱ—O5ⁱⁱ	85.32 (18)
O5ⁱⁱ—Rb1—Rb2ⁱⁱⁱ	45.88 (10)	Rb2—As2ⁱⁱ—O7ⁱⁱ	57.51 (18)
O6ⁱⁱⁱ—Rb1—O7ⁱⁱ	141.79 (13)	Rb2—As2ⁱⁱ—O6ⁱⁱ	162.87 (18)
O6ⁱⁱⁱ—Rb1—O8	114.7 (2)	Rb2—As2ⁱⁱ—O8ⁱⁱ	63.3 (4)
O6ⁱⁱⁱ—Rb1—Rb2^iv	67.84 (9)	O5ⁱⁱ—As2ⁱⁱ—O7ⁱⁱ	105.3 (3)
O6ⁱⁱⁱ—Rb1—Rb2ⁱⁱⁱ	70.99 (10)	O5ⁱⁱ—As2ⁱⁱ—O6ⁱⁱ	111.6 (3)
O7ⁱⁱ—Rb1—O8	103.3 (2)	O5ⁱⁱ—As2ⁱⁱ—O8ⁱⁱ	112.1 (3)
O7ⁱⁱ—Rb1—Rb2^iv	94.05 (9)	O7ⁱⁱ—As2ⁱⁱ—O6ⁱⁱ	112.7 (3)
O7ⁱⁱ—Rb1—Rb2ⁱⁱⁱ	88.63 (10)	O7ⁱⁱ—As2ⁱⁱ—O8ⁱⁱ	104.5 (4)
O8—Rb1—Rb2^iv	113.3 (3)	O6ⁱⁱ—As2ⁱⁱ—O8ⁱⁱ	110.3 (4)
O8—Rb1—Rb2ⁱⁱⁱ	129.3 (2)	Rb1—O1—Ti1	96.5 (2)
Rb2^iv—Rb1—Rb2ⁱⁱⁱ	114.75 (3)	Rb1—O1—As1	88.3 (2)
Rb1—Rb2—As2ⁱⁱ	54.15 (3)	Rb1—O1—Rb2ⁱⁱⁱ	86.85 (16)
Rb1—Rb2—O4^v	78.03 (9)	Ti1—O1—As1	129.5 (3)
Rb1—Rb2—O11	45.21 (11)	Ti1—O1—Rb2ⁱⁱⁱ	100.7 (2)
Rb1—Rb2—O7ⁱⁱ	45.89 (10)	As1—O1—Rb2ⁱⁱⁱ	129.8 (3)
Rb1—Rb2—Rb1^ix	118.98 (3)	Rb1—O2—As1	98.2 (2)
Rb1—Rb2—O3ⁱⁱ	127.63 (9)	Rb1—O2—Ti1^x	122.1 (3)
Rb1—Rb2—O12ⁱⁱ	80.30 (10)	Rb1—O2—Rb2^xi	106.75 (17)
Rb1—Rb2—O2ⁱⁱ	135.24 (11)	As1—O2—Ti1^x	129.6 (3)
Rb1—Rb2—O8ⁱⁱ	81.6 (2)	As1—O2—Rb2^xi	101.4 (2)
Rb1—Rb2—Rb1^vi	100.44 (4)	Ti1^x—O2—Rb2^xi	94.9 (2)
Rb1—Rb2—O1^vi	102.03 (12)	Rb1—O3ⁱ—Ti2ⁱ	103.6 (2)
Rb1—Rb2—O5^vii	147.63 (10)	Rb1—O3ⁱ—As1ⁱ	128.2 (2)
As2ⁱⁱ—Rb2—O4^v	128.24 (9)	Rb1—O3ⁱ—Rb2^iv	79.76 (14)
As2ⁱⁱ—Rb2—O11	75.57 (11)	Ti2ⁱ—O3ⁱ—As1ⁱ	127.6 (3)
As2ⁱⁱ—Rb2—O7ⁱⁱ	28.76 (10)	Ti2ⁱ—O3ⁱ—Rb2^iv	97.7 (2)
As2ⁱⁱ—Rb2—Rb1^ix	105.37 (4)	As1ⁱ—O3ⁱ—Rb2^iv	98.7 (2)
As2ⁱⁱ—Rb2—O3ⁱⁱ	80.12 (9)	Rb2—O4^v—Ti2	98.32 (18)
As2ⁱⁱ—Rb2—O12ⁱⁱ	58.56 (10)	Rb2—O4^v—As1^v	126.1 (2)
As2ⁱⁱ—Rb2—O2ⁱⁱ	86.66 (11)	Ti2—O4^v—As1^v	131.7 (3)
As2ⁱⁱ—Rb2—O8ⁱⁱ	28.0 (2)	Rb1—O11—Rb2	95.86 (15)
As2ⁱⁱ—Rb2—Rb1^vi	133.53 (3)	Rb1—O11—Ti1	95.7 (2)
As2ⁱⁱ—Rb2—O1^vi	93.52 (12)	Rb1—O11—Ti2	99.4 (2)
As2ⁱⁱ—Rb2—O5^vii	139.64 (10)	Rb2—O11—Ti1	101.3 (2)
O4^v—Rb2—O11	55.36 (13)	Rb2—O11—Ti2	111.0 (2)
O4^v—Rb2—O7ⁱⁱ	122.21 (14)	Ti1—O11—Ti2	142.5 (3)
O4^v—Rb2—Rb1^ix	79.37 (10)	Rb1—O12ⁱ—Ti2ⁱ	96.01 (19)
O4^v—Rb2—O3ⁱⁱ	124.48 (14)	Rb1—O12ⁱ—Rb2^iv	77.59 (13)
O4^v—Rb2—O12ⁱⁱ	98.57 (14)	Rb1—O12ⁱ—Ti1^iv	124.3 (3)
O4^v—Rb2—O2ⁱⁱ	144.97 (14)	Ti2ⁱ—O12ⁱ—Rb2^iv	96.3 (2)
O4^v—Rb2—O8ⁱⁱ	146.26 (14)	Ti2ⁱ—O12ⁱ—Ti1^iv	139.1 (3)
O4^v—Rb2—Rb1^vi	67.41 (9)	Rb2^iv—O12ⁱ—Ti1^iv	98.5 (2)
O4^v—Rb2—O1^vi	116.93 (15)	Rb1—O5ⁱⁱ—Ti1	101.92 (19)
O4^v—Rb2—O5^vii	91.23 (13)	Rb1—O5ⁱⁱ—As2ⁱⁱ	105.2 (2)
O11—Rb2—O7ⁱⁱ	85.16 (15)	Rb1—O5ⁱⁱ—Rb2ⁱⁱⁱ	86.44 (14)
O11—Rb2—Rb1^ix	75.58 (11)	Ti1—O5ⁱⁱ—As2ⁱⁱ	130.4 (3)
O11—Rb2—O3ⁱⁱ	104.87 (14)	Ti1—O5ⁱⁱ—Rb2ⁱⁱⁱ	97.77 (19)
O11—Rb2—O12ⁱⁱ	54.37 (14)	As2ⁱⁱ—O5ⁱⁱ—Rb2ⁱⁱⁱ	124.4 (2)
O11—Rb2—O2ⁱⁱ	152.23 (15)	Rb1—O6ⁱⁱⁱ—Ti1^x	97.83 (19)
O11—Rb2—O8ⁱⁱ	91.38 (16)	Rb1—O6ⁱⁱⁱ—As2ⁱⁱⁱ	128.5 (2)
O11—Rb2—Rb1^vi	116.07 (11)	Ti1^x—O6ⁱⁱⁱ—As2ⁱⁱⁱ	133.4 (3)
O11—Rb2—O1^vi	145.63 (16)	Rb1—O7ⁱⁱ—Rb2	93.21 (14)
O11—Rb2—O5^vii	144.64 (15)	Rb1—O7ⁱⁱ—Ti2ⁱ	89.18 (17)
O7ⁱⁱ—Rb2—Rb1^ix	134.07 (10)	Rb1—O7ⁱⁱ—As2ⁱⁱ	93.8 (2)
O7ⁱⁱ—Rb2—O3ⁱⁱ	103.75 (13)	Rb2—O7ⁱⁱ—Ti2ⁱ	140.1 (3)
O7ⁱⁱ—Rb2—O12ⁱⁱ	86.35 (14)	Rb2—O7ⁱⁱ—As2ⁱⁱ	93.7 (2)
O7ⁱⁱ—Rb2—O2ⁱⁱ	89.37 (15)	Ti2ⁱ—O7ⁱⁱ—As2ⁱⁱ	125.9 (3)
O7ⁱⁱ—Rb2—O8ⁱⁱ	51.2 (2)	Rb1—O8—Ti2	109.3 (6)
O7ⁱⁱ—Rb2—Rb1^vi	104.87 (10)	Rb1—O8—Rb2^xi	104.7 (2)
O7ⁱⁱ—Rb2—O1^vi	71.77 (16)	Rb1—O8—As2	114.3 (4)
O7ⁱⁱ—Rb2—O5^vii	126.83 (15)	Ti2—O8—Rb2^xi	99.0 (2)
Rb1^ix—Rb2—O3ⁱⁱ	45.33 (9)	Ti2—O8—As2	132.0 (3)
Rb1^ix—Rb2—O12ⁱⁱ	48.56 (10)	Rb2^xi—O8—As2	88.7 (6)

Experimental details

	(LowT)	(RoomT)
Crystal data
Chemical formula	RbTiOAsO₄	RbTiOAsO₄
M_r	288.27	288.27
Crystal system, space group	Orthorhombic, Pna2₁	Orthorhombic, Pna2₁
Temperature (K)	10	295
a, b, c (Å)	13.218 (1), 6.6500 (9), 10.761 (1)	13.261 (2), 6.6791 (8), 10.769 (1)
V (Å³)	945.89 (17)	953.8 (2)
Z	8	8
Radiation type	Mo Kα	Mo Kα
µ (mm⁻¹)	18.90	18.74
Crystal size (mm)	0.58 × 0.54 × 0.36	0.58 × 0.54 × 0.36

Data collection
Diffractometer	Huber 512 diffractometer	Huber 512 diffractometer
Absorption correction	Analytical Alcock (1974)	Analytical Alcock (1974)
T_min, T_max	0.008, 0.066	0.008, 0.066
No. of measured, independent and observed reflections	15878, 5090, 5020 [refl observed if F > 2 σ(F )]	9854, 5125, 4852 [refl observed if F > 2 σ(F )]
R_int	0.022	0.055
(sin θ/λ)_max (Å⁻¹)	1.080	1.079

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.026, 4.60	0.055, 0.043, 4.76
No. of reflections	5006	4796
No. of parameters	146	146
No. of restraints	?	?
Δρ_max, Δρ_min (e Å⁻³)	1.53, −1.84	3.06, −2.84
Absolute structure	Flack XABS refined	Flack XABS refined
Absolute structure parameter	0.546 (6)	0.59 (1)

Computer programs: Xtal DIFDAT ADDREF ABSORB SORTRF, Xtal CRYLSQ, Xtal CIFIO.

Atom to plane distances to selected least-squares planes in the Ti octahedra (Å) top

Plane	LowT	RoomT	Plane	LowT	RoomT

Ti1	0.020 (1)	0.014 (2)	Ti2	0.015 (1)	0.009 (2)
O1	0.118 (3)	0.126 (7)	O7^iv	0.010 (4)	0.013 (8)
O2^vii	0.056 (3)	0.050 (7)	O8	0.076 (9)	0.08 (2)
O11	0.054 (3)	0.044 (7)	O11	0.049 (3)	0.052 (7)
O12ⁱⁱⁱ	0.137 (3)	0.134 (7)	O12	0.040 (3)	0.042 (7)

Ti1	0.010 (1)	0.007 (2)	Ti2	0.029 (1)	0.021 (1)
O1	0.018 (3)	0.019 (7)	O3	0.096 (3)	0.104 (7)
O5ⁱⁱⁱ	0.044 (3)	0.050 (7)	O4^vi	0.106 (3)	0.112 (7)
O6^iv	0.049 (3)	0.057 (7)	O7^iv	0.001 (4)	0.036 (8)
O12ⁱⁱⁱ	0.007 (3)	0.005 (7)	O8	0.001 (8)	0.29 (2)

Selected geometric parameters (Å, °) top

	LowT	RoomT

Rb1-O1	3.071 (3)	3.125 (6)
Rb1-O11	3.209 (3)	3.268 (5)
Rb1-O12ⁱ	2.932 (3)	2.937 (6)
Rb1-O6ⁱⁱ	3.434 (3)	3.392 (6)
Rb2-O11	2.891 (3)	2.893 (5)
Rb2-O12ⁱⁱⁱ	3.131 (3)	3.163 (5)
Rb2-O2ⁱⁱⁱ	3.063 (3)	3.099 (6)
Ti1-O1	2.150 (3)	2.147 (6)
Ti1-O11	1.977 (3)	1.982 (5)
Ti1-O2^vii	1.942 (3)	1.950 (5)
Ti1-O5ⁱⁱⁱ	2.058 (3)	2.072 (5)
Ti1-O6^iv	2.023 (3)	2.036 (5)
Ti1-O12ⁱⁱⁱ	1.722 (3)	1.716 (5)
Ti2-O3	2.038 (2)	2.042 (5)
Ti2-O12	2.121 (3)	2.131 (5)
Ti2-O7^iv	1.950 (3)	1.950 (5)
Ti2-O4^vi	2.002 (2)	2.005 (5)
Ti2-O11	1.744 (3)	1.745 (5)
Ti2-O8	1.980 (7)	1.989 (13)
As1-O1	1.644 (3)	1.646 (6)
As1-O2	1.701 (3)	1.703 (5)
As1-O3	1.688 (2)	1.689 (5)
As1-O4	1.684 (2)	1.684 (5)
As2-O5	1.682 (3)	1.689 (5)
As2-O7	1.706 (3)	1.713 (5)
As2-O6	1.673 (3)	1.678 (5)
As2-O8	1.675 (6)	1.669 (13)

O1-Rb1-O11	51.58 (7)	50.65 (14)
O1-Rb1-O12ⁱ	152.65 (7)	150.65 (15)
O11-Rb1-O12ⁱ	105.77 (7)	104.90 (14)
O11-Rb2-O12ⁱⁱⁱ	54.82 (7)	54.37 (14)
O11-Rb2-O2ⁱⁱⁱ	153.49 (7)	152.23 (15)
O12ⁱⁱⁱ-Rb2-O2ⁱⁱⁱ	99.13 (7)	98.17 (14)
O3-As1-O4	108.85 (12)	109.6 (2)
O5-As2-O7	106.09 (13)	105.3 (3)
Ti2-O4^vi-As1^vi	130.89 (14)	131.7 (3)

Symmetry codes: (i) x, 1 + y, z; (ii) 1/2 + x, 3/2 - y, z; (iii) 1/2 - x, 1/2 + y, 1/2 + z; (iv) 1/2-x, y-1/2, 1/2+z; (v) x - 1/2, 3/2 - y, z; (vi) x - 1/2, 1/2 - y, z; (vii) 1 - x, 1 - y, 1/2 + z.

Thermal displacements along principal axes and angles between the principal axes and the c axis of the unit cell (Å, °) top

		LowT	Angle	RoomT	Angle

Rb1	r₁	0.047 (1)	81 (6)	0.096 (2)	85 (1)
	r₂	0.056 (1)	143 (4)	0.134 (1)	123.5 (9)
	r₃	0.0663 (8)	126 (3)	0.188 (1)	33.9 (8)
Rb2	r₁	0.049 (1)	93 (6)	0.099 (2)	90 (1)
	r₂	0.055 (1)	125 (10)	0.130 (1)	108 (2)
	r₃	0.059 (1)	35 (10)	0.158 (1)	18 (2)
O3	r₁	0.045 (9)	85 (17)	0.07 (1)	97 (11)
	r₂	0.062 (8)	131 (18)	0.09 (1)	103 (11)
	r₃	0.077 (7)	41 (18)	0.14 (1)	14 (10)
O4	r₁	0.051 (9)	99 (19)	0.061 (9)	84 (9)
	r₂	0.067 (8)	141 (26)	0.09 (1)	85 (14)
	r₃	0.077 (7)	53 (26)	0.13 (1)	8(12)
O6	r₁	0.05 (1)	109 (16)	0.07 (2)	90 (90)
	r₂	0.068 (7)	142 (18)	0.11 (1)	67 (10)
	r₃	0.083 (6)	59 (16)	0.15 (1)	23 (10)

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