Structure of and electron density in RbTiOAsO₄ at 9.6 K

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.

Computing details

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

(LowT)

Crystal data

RbTiOAsO4	Dx = 4.048 Mg m^−3
Mr = 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) Å^3	0.58 × 0.54 × 0.36 mm
Z = 8

Data collection

Huber 512 diffractometer	Rint = 0.022
profile data from ω/2θ scans	θmax = 50.1°, θmin = 3.1°
Absorption correction: analytical Alcock (1974)	h = −15→28
Tmin = 0.008, Tmax = 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

Refinement on F	(Δ/σ)max = 0.385-03
Least-squares matrix: full	Δρmax = 1.53 e Å^−3
R[F^2 > 2σ(F^2)] = 0.032	Δρmin = −1.84 e Å^−3
wR(F^2) = 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/σ^2

Special details

Refinement. Sfls F σ weight full matrix

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
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 (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
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)

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—O5^ii	2.058 (3)
Rb1—O3^i	2.749 (3)	Ti1—O2^viii	1.942 (3)
Rb1—O11	3.209 (3)	Ti1—O6^ix	2.023 (3)
Rb1—O12^i	2.932 (3)	Ti1—O12^ii	1.722 (3)
Rb1—O5^ii	2.959 (3)	Ti2^i—O3^i	2.038 (2)
Rb1—O6^iii	3.434 (3)	Ti2^i—O12^i	2.121 (3)
Rb1—O7^ii	3.254 (3)	Ti2^i—O7^ii	1.950 (3)
Rb1—O8	2.799 (3)	Ti2^i—O4^vi	2.002 (2)
Rb1—Rb2^iv	3.8232 (8)	Ti2^i—O11^i	1.744 (3)
Rb1—Rb2^iii	4.0503 (7)	Ti2^i—O8^i	1.980 (7)
Rb2—As2^ii	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—O7^ii	3.004 (3)	As1—O4	1.684 (2)
Rb2—O3^ii	3.135 (3)	As2^ii—O5^ii	1.682 (3)
Rb2—O12^ii	3.131 (3)	As2^ii—O7^ii	1.706 (3)
Rb2—O2^ii	3.063 (3)	As2^ii—O6^ii	1.673 (3)
Rb2—O8^ii	3.144 (5)	As2^ii—O8^ii	1.675 (6)
Rb2—O1^vi	2.757 (3)
Rb2—Rb1—As1	97.056 (15)	Rb1^ix—Rb2—O2^ii	89.80 (5)
Rb2—Rb1—O1	84.57 (5)	Rb1^ix—Rb2—O8^ii	87.73 (11)
Rb2—Rb1—O2	122.45 (6)	Rb1^ix—Rb2—Rb1^vi	121.488 (11)
Rb2—Rb1—O3^i	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—O12^i	69.13 (5)	O3^ii—Rb2—O12^ii	52.64 (7)
Rb2—Rb1—O5^ii	56.00 (5)	O3^ii—Rb2—O2^ii	50.91 (7)
Rb2—Rb1—O6^iii	170.93 (5)	O3^ii—Rb2—O8^ii	53.59 (13)
Rb2—Rb1—O7^ii	41.20 (5)	O3^ii—Rb2—Rb1^vi	131.14 (5)
Rb2—Rb1—O8	66.32 (13)	O3^ii—Rb2—O1^vi	106.30 (7)
Rb2—Rb1—Rb2^iv	122.241 (11)	O3^ii—Rb2—O5^vii	84.30 (7)
Rb2—Rb1—Rb2^iii	101.164 (18)	O12^ii—Rb2—O2^ii	99.13 (7)
As1—Rb1—O1	28.38 (5)	O12^ii—Rb2—O8^ii	51.64 (8)
As1—Rb1—O2	29.23 (6)	O12^ii—Rb2—Rb1^vi	165.49 (5)
As1—Rb1—O3^i	142.39 (5)	O12^ii—Rb2—O1^vi	145.14 (8)
As1—Rb1—O11	58.02 (5)	O12^ii—Rb2—O5^vii	132.98 (7)
As1—Rb1—O12^i	157.85 (5)	O2^ii—Rb2—O8^ii	64.85 (9)
As1—Rb1—O5^ii	79.83 (5)	O2^ii—Rb2—Rb1^vi	90.84 (5)
As1—Rb1—O6^iii	74.73 (4)	O2^ii—Rb2—O1^vi	55.46 (8)
As1—Rb1—O7^ii	126.81 (5)	O2^ii—Rb2—O5^vii	55.26 (7)
As1—Rb1—O8	69.61 (7)	O8^ii—Rb2—Rb1^vi	142.87 (6)
As1—Rb1—Rb2^iv	138.60 (2)	O8^ii—Rb2—O1^vi	93.77 (8)
As1—Rb1—Rb2^iii	64.441 (13)	O8^ii—Rb2—O5^vii	120.02 (9)
O1—Rb1—O2	54.40 (7)	Rb1^vi—Rb2—O1^vi	49.27 (6)
O1—Rb1—O3^i	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—O12^i	152.65 (7)	O1—Ti1—O11	82.92 (11)
O1—Rb1—O5^ii	52.08 (7)	O1—Ti1—O5^ii	77.99 (10)
O1—Rb1—O6^iii	86.36 (7)	O1—Ti1—O2^viii	83.19 (11)
O1—Rb1—O7^ii	102.05 (7)	O1—Ti1—O6^ix	86.56 (11)
O1—Rb1—O8	87.45 (12)	O1—Ti1—O12^ii	171.11 (12)
O1—Rb1—Rb2^iv	150.99 (5)	O11—Ti1—O5^ii	92.39 (11)
O1—Rb1—Rb2^iii	42.86 (5)	O11—Ti1—O2^viii	165.79 (12)
O2—Rb1—O3^i	138.44 (7)	O11—Ti1—O6^ix	88.84 (11)
O2—Rb1—O11	83.97 (7)	O11—Ti1—O12^ii	97.25 (12)
O2—Rb1—O12^i	148.09 (8)	O5^ii—Ti1—O2^viii	87.60 (11)
O2—Rb1—O5^ii	106.16 (7)	O5^ii—Ti1—O6^ix	164.22 (11)
O2—Rb1—O6^iii	50.85 (7)	O5^ii—Ti1—O12^ii	93.12 (12)
O2—Rb1—O7^ii	155.93 (7)	O2^viii—Ti1—O6^ix	87.39 (11)
O2—Rb1—O8	72.73 (8)	O2^viii—Ti1—O12^ii	96.93 (13)
O2—Rb1—Rb2^iv	109.67 (6)	O6^ix—Ti1—O12^ii	102.33 (12)
O2—Rb1—Rb2^iii	76.35 (5)	O3^i—Ti2^i—O12^i	83.82 (10)
O3^i—Rb1—O11	126.27 (7)	O3^i—Ti2^i—O7^ii	86.23 (11)
O3^i—Rb1—O12^i	58.45 (7)	O3^i—Ti2^i—O4^vi	172.59 (11)
O3^i—Rb1—O5^ii	77.25 (7)	O3^i—Ti2^i—O11^i	92.77 (12)
O3^i—Rb1—O6^iii	90.13 (7)	O3^i—Ti2^i—O8^i	89.56 (11)
O3^i—Rb1—O7^ii	53.22 (7)	O12^i—Ti2^i—O7^ii	85.75 (11)
O3^i—Rb1—O8	146.69 (8)	O12^i—Ti2^i—O4^vi	88.78 (10)
O3^i—Rb1—Rb2^iv	54.03 (6)	O12^i—Ti2^i—O11^i	175.50 (12)
O3^i—Rb1—Rb2^iii	78.23 (5)	O12^i—Ti2^i—O8^i	83.50 (18)
O11—Rb1—O12^i	105.77 (7)	O7^ii—Ti2^i—O4^vi	92.95 (11)
O11—Rb1—O5^ii	56.17 (7)	O7^ii—Ti2^i—O11^i	96.97 (12)
O11—Rb1—O6^iii	132.73 (7)	O7^ii—Ti2^i—O8^i	168.82 (18)
O11—Rb1—O7^ii	75.83 (7)	O4^vi—Ti2^i—O11^i	94.64 (12)
O11—Rb1—O8	53.28 (17)	O4^vi—Ti2^i—O8^i	89.89 (11)
O11—Rb1—Rb2^iv	157.39 (5)	O11^i—Ti2^i—O8^i	93.57 (18)
O11—Rb1—Rb2^iii	85.89 (5)	Rb1—As1—O1	62.64 (9)
O12^i—Rb1—O5^ii	104.35 (7)	Rb1—As1—O2	53.94 (9)
O12^i—Rb1—O6^iii	119.87 (7)	Rb1—As1—O3	95.02 (8)
O12^i—Rb1—O7^ii	52.95 (7)	Rb1—As1—O4	154.83 (9)
O12^i—Rb1—O8	88.68 (9)	O1—As1—O2	107.67 (13)
O12^i—Rb1—Rb2^iv	53.26 (5)	O1—As1—O3	113.21 (13)
O12^i—Rb1—Rb2^iii	133.63 (5)	O1—As1—O4	112.43 (13)
O5^ii—Rb1—O6^iii	117.69 (7)	O2—As1—O3	103.72 (13)
O5^ii—Rb1—O7^ii	51.40 (7)	O2—As1—O4	110.62 (13)
O5^ii—Rb1—O8	109.14 (17)	O3—As1—O4	108.85 (12)
O5^ii—Rb1—Rb2^iv	131.27 (5)	Rb2—As2^ii—O5^ii	85.60 (9)
O5^ii—Rb1—Rb2^iii	45.71 (5)	Rb2—As2^ii—O7^ii	58.04 (9)
O6^iii—Rb1—O7^ii	142.06 (6)	Rb2—As2^ii—O6^ii	163.21 (9)
O6^iii—Rb1—O8	113.17 (12)	Rb2—As2^ii—O8^ii	62.77 (18)
O6^iii—Rb1—Rb2^iv	66.68 (4)	O5^ii—As2^ii—O7^ii	106.09 (13)
O6^iii—Rb1—Rb2^iii	72.02 (5)	O5^ii—As2^ii—O6^ii	110.98 (12)
O7^ii—Rb1—O8	104.19 (12)	O5^ii—As2^ii—O8^ii	111.70 (13)
O7^ii—Rb1—Rb2^iv	93.72 (5)	O7^ii—As2^ii—O6^ii	112.46 (13)
O7^ii—Rb1—Rb2^iii	89.12 (5)	O7^ii—As2^ii—O8^ii	104.5 (2)
O8—Rb1—Rb2^iv	112.28 (15)	O6^ii—As2^ii—O8^ii	110.87 (19)
O8—Rb1—Rb2^iii	130.30 (12)	Rb1—O1—Ti1	95.80 (9)
Rb2^iv—Rb1—Rb2^iii	114.353 (12)	Rb1—O1—As1	88.98 (11)
Rb1—Rb2—As2^ii	53.530 (14)	Rb1—O1—Rb2^iii	87.88 (7)
Rb1—Rb2—O4^v	77.34 (5)	Ti1—O1—As1	128.82 (15)
Rb1—Rb2—O11	44.47 (5)	Ti1—O1—Rb2^iii	99.91 (10)
Rb1—Rb2—O7^ii	45.54 (5)	As1—O1—Rb2^iii	131.23 (14)
Rb1—Rb2—Rb1^ix	118.896 (11)	Rb1—O2—As1	96.83 (11)
Rb1—Rb2—O3^ii	127.64 (4)	Rb1—O2—Ti1^x	123.21 (12)
Rb1—Rb2—O12^ii	79.90 (5)	Rb1—O2—Rb2^xi	107.32 (8)
Rb1—Rb2—O2^ii	134.89 (5)	As1—O2—Ti1^x	129.53 (15)
Rb1—Rb2—O8^ii	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—O3^i—Ti2^i	103.40 (9)
Rb1—Rb2—O5^vii	146.89 (5)	Rb1—O3^i—As1^i	128.55 (12)
As2^ii—Rb2—O4^v	127.61 (5)	Rb1—O3^i—Rb2^iv	80.76 (7)
As2^ii—Rb2—O11	75.41 (6)	Ti2^i—O3^i—As1^i	127.34 (14)
As2^ii—Rb2—O7^ii	28.82 (5)	Ti2^i—O3^i—Rb2^iv	97.63 (9)
As2^ii—Rb2—Rb1^ix	105.768 (18)	As1^i—O3^i—Rb2^iv	98.49 (11)
As2^ii—Rb2—O3^ii	80.84 (5)	Rb2—O4^v—Ti2	98.27 (9)
As2^ii—Rb2—O12^ii	58.92 (5)	Rb2—O4^v—As1^v	126.05 (12)
As2^ii—Rb2—O2^ii	87.04 (5)	Ti2—O4^v—As1^v	130.89 (14)
As2^ii—Rb2—O8^ii	28.28 (12)	Rb1—O11—Rb2	96.40 (8)
As2^ii—Rb2—Rb1^vi	132.694 (18)	Rb1—O11—Ti1	95.37 (10)
As2^ii—Rb2—O1^vi	93.31 (6)	Rb1—O11—Ti2	99.79 (11)
As2^ii—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—O7^ii	120.72 (7)	Ti1—O11—Ti2	142.63 (16)
O4^v—Rb2—Rb1^ix	80.88 (5)	Rb1—O12^i—Ti2^i	95.60 (9)
O4^v—Rb2—O3^ii	125.84 (7)	Rb1—O12^i—Rb2^iv	78.11 (6)
O4^v—Rb2—O12^ii	99.35 (7)	Rb1—O12^i—Ti1^iv	124.81 (13)
O4^v—Rb2—O2^ii	145.34 (7)	Ti2^i—O12^i—Rb2^iv	95.95 (9)
O4^v—Rb2—O8^ii	146.78 (7)	Ti2^i—O12^i—Ti1^iv	139.01 (15)
O4^v—Rb2—Rb1^vi	66.87 (5)	Rb2^iv—O12^i—Ti1^iv	98.69 (11)
O4^v—Rb2—O1^vi	114.99 (7)	Rb1—O5^ii—Ti1	101.35 (9)
O4^v—Rb2—O5^vii	91.04 (7)	Rb1—O5^ii—As2^ii	104.55 (11)
O11—Rb2—O7^ii	84.70 (7)	Rb1—O5^ii—Rb2^iii	87.41 (7)
O11—Rb2—Rb1^ix	76.42 (5)	Ti1—O5^ii—As2^ii	130.94 (14)
O11—Rb2—O3^ii	105.80 (7)	Ti1—O5^ii—Rb2^iii	97.72 (9)
O11—Rb2—O12^ii	54.82 (7)	As2^ii—O5^ii—Rb2^iii	124.16 (12)
O11—Rb2—O2^ii	153.49 (7)	Rb1—O6^iii—Ti1^x	97.46 (9)
O11—Rb2—O8^ii	91.71 (8)	Rb1—O6^iii—As2^iii	128.34 (12)
O11—Rb2—Rb1^vi	115.66 (6)	Ti1^x—O6^iii—As2^iii	133.65 (15)
O11—Rb2—O1^vi	143.63 (8)	Rb1—O7^ii—Rb2	93.26 (7)
O11—Rb2—O5^vii	144.71 (7)	Rb1—O7^ii—Ti2^i	89.60 (9)
O7^ii—Rb2—Rb1^ix	134.53 (5)	Rb1—O7^ii—As2^ii	93.03 (10)
O7^ii—Rb2—O3^ii	104.49 (7)	Rb2—O7^ii—Ti2^i	140.92 (12)
O7^ii—Rb2—O12^ii	86.75 (7)	Rb2—O7^ii—As2^ii	93.15 (10)
O7^ii—Rb2—O2^ii	89.38 (7)	Ti2^i—O7^ii—As2^ii	125.63 (15)
O7^ii—Rb2—O8^ii	51.50 (13)	Rb1—O8—Ti2	108.3 (3)
O7^ii—Rb2—Rb1^vi	103.98 (5)	Rb1—O8—Rb2^xi	105.57 (11)
O7^ii—Rb2—O1^vi	71.12 (8)	Rb1—O8—As2	115.05 (18)
O7^ii—Rb2—O5^vii	126.22 (7)	Ti2—O8—Rb2^xi	98.65 (10)
Rb1^ix—Rb2—O3^ii	45.21 (5)	Ti2—O8—As2	131.98 (16)
Rb1^ix—Rb2—O12^ii	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)

Crystal data

RbTiOAsO4	Dx = 4.015 Mg m^−3
Mr = 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) Å^3	0.58 × 0.54 × 0.36 mm
Z = 8

Data collection

Huber 512 diffractometer	Rint = 0.055
profile data from ω/2θ scans	θmax = 50.1°, θmin = 3.1°
Absorption correction: analytical Alcock (1974)	h = 0→28
Tmin = 0.008, Tmax = 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

Refinement on F	(Δ/σ)max = 0.255-03
Least-squares matrix: full	Δρmax = 3.06 e Å^−3
R[F^2 > 2σ(F^2)] = 0.055	Δρmin = −2.84 e Å^−3
wR(F^2) = 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/σ^2

Special details

Refinement. Sfls F σ weight full matrix

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
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 (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
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)

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—O5^ii	2.072 (5)
Rb1—O3^i	2.765 (5)	Ti1—O2^viii	1.950 (5)
Rb1—O11	3.268 (5)	Ti1—O6^ix	2.036 (5)
Rb1—O12^i	2.937 (6)	Ti1—O12^ii	1.716 (5)
Rb1—O5^ii	3.004 (5)	Ti2^i—O3^i	2.042 (5)
Rb1—O6^iii	3.392 (6)	Ti2^i—O12^i	2.131 (5)
Rb1—O7^ii	3.294 (5)	Ti2^i—O7^ii	1.950 (5)
Rb1—O8	2.816 (7)	Ti2^i—O4^vi	2.005 (5)
Rb1—Rb2^iv	3.8255 (16)	Ti2^i—O11^i	1.745 (5)
Rb1—Rb2^iii	4.0545 (16)	Ti2^i—O8^i	1.989 (13)
Rb2—As2^ii	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—O7^ii	3.004 (6)	As1—O4	1.684 (5)
Rb2—O3^ii	3.181 (6)	As2^ii—O5^ii	1.689 (5)
Rb2—O12^ii	3.163 (5)	As2^ii—O7^ii	1.713 (5)
Rb2—O2^ii	3.099 (6)	As2^ii—O6^ii	1.678 (5)
Rb2—O8^ii	3.174 (11)	As2^ii—O8^ii	1.669 (13)
Rb2—O1^vi	2.761 (6)
Rb2—Rb1—As1	96.27 (3)	Rb1^ix—Rb2—O2^ii	89.15 (11)
Rb2—Rb1—O1	83.64 (11)	Rb1^ix—Rb2—O8^ii	87.5 (2)
Rb2—Rb1—O2	121.46 (11)	Rb1^ix—Rb2—Rb1^vi	121.05 (3)
Rb2—Rb1—O3^i	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—O12^i	68.15 (10)	O3^ii—Rb2—O12^ii	52.21 (13)
Rb2—Rb1—O5^ii	55.71 (10)	O3^ii—Rb2—O2^ii	50.23 (13)
Rb2—Rb1—O6^iii	169.98 (10)	O3^ii—Rb2—O8^ii	53.1 (3)
Rb2—Rb1—O7^ii	40.90 (10)	O3^ii—Rb2—Rb1^vi	131.27 (9)
Rb2—Rb1—O8	65.2 (3)	O3^ii—Rb2—O1^vi	105.14 (14)
Rb2—Rb1—Rb2^iv	121.87 (3)	O3^ii—Rb2—O5^vii	83.62 (13)
Rb2—Rb1—Rb2^iii	101.03 (4)	O12^ii—Rb2—O2^ii	98.17 (14)
As1—Rb1—O1	28.13 (10)	O12^ii—Rb2—O8^ii	51.27 (16)
As1—Rb1—O2	28.90 (11)	O12^ii—Rb2—Rb1^vi	165.21 (10)
As1—Rb1—O3^i	141.72 (11)	O12^ii—Rb2—O1^vi	144.25 (15)
As1—Rb1—O11	57.42 (10)	O12^ii—Rb2—O5^vii	131.84 (14)
As1—Rb1—O12^i	157.41 (11)	O2^ii—Rb2—O8^ii	64.49 (18)
As1—Rb1—O5^ii	78.92 (10)	O2^ii—Rb2—Rb1^vi	91.65 (10)
As1—Rb1—O6^iii	74.92 (9)	O2^ii—Rb2—O1^vi	54.98 (15)
As1—Rb1—O7^ii	125.17 (10)	O2^ii—Rb2—O5^vii	55.11 (14)
As1—Rb1—O8	69.40 (15)	O8^ii—Rb2—Rb1^vi	143.51 (13)
As1—Rb1—Rb2^iv	139.87 (4)	O8^ii—Rb2—O1^vi	93.39 (17)
As1—Rb1—Rb2^iii	63.85 (3)	O8^ii—Rb2—O5^vii	119.5 (2)
O1—Rb1—O2	53.95 (14)	Rb1^vi—Rb2—O1^vi	50.32 (12)
O1—Rb1—O3^i	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—O12^i	150.65 (15)	O1—Ti1—O11	83.0 (2)
O1—Rb1—O5^ii	51.37 (14)	O1—Ti1—O5^ii	78.1 (2)
O1—Rb1—O6^iii	86.36 (14)	O1—Ti1—O2^viii	83.1 (2)
O1—Rb1—O7^ii	100.49 (14)	O1—Ti1—O6^ix	86.7 (2)
O1—Rb1—O8	86.5 (3)	O1—Ti1—O12^ii	171.3 (2)
O1—Rb1—Rb2^iv	152.10 (11)	O11—Ti1—O5^ii	92.3 (2)
O1—Rb1—Rb2^iii	42.83 (11)	O11—Ti1—O2^viii	165.7 (2)
O2—Rb1—O3^i	139.30 (16)	O11—Ti1—O6^ix	89.3 (2)
O2—Rb1—O11	83.17 (15)	O11—Ti1—O12^ii	97.1 (2)
O2—Rb1—O12^i	149.91 (15)	O5^ii—Ti1—O2^viii	87.7 (2)
O2—Rb1—O5^ii	105.00 (15)	O5^ii—Ti1—O6^ix	164.4 (2)
O2—Rb1—O6^iii	51.52 (14)	O5^ii—Ti1—O12^ii	93.3 (2)
O2—Rb1—O7^ii	153.94 (14)	O2^viii—Ti1—O6^ix	87.1 (2)
O2—Rb1—O8	73.01 (17)	O2^viii—Ti1—O12^ii	97.2 (2)
O2—Rb1—Rb2^iv	111.27 (11)	O6^ix—Ti1—O12^ii	102.0 (2)
O2—Rb1—Rb2^iii	75.50 (11)	O3^i—Ti2^i—O12^i	84.0 (2)
O3^i—Rb1—O11	124.72 (15)	O3^i—Ti2^i—O7^ii	86.2 (2)
O3^i—Rb1—O12^i	58.53 (15)	O3^i—Ti2^i—O4^vi	172.6 (2)
O3^i—Rb1—O5^ii	76.38 (15)	O3^i—Ti2^i—O11^i	92.9 (2)
O3^i—Rb1—O6^iii	90.78 (14)	O3^i—Ti2^i—O8^i	89.6 (2)
O3^i—Rb1—O7^ii	52.66 (14)	O12^i—Ti2^i—O7^ii	85.8 (2)
O3^i—Rb1—O8	146.55 (16)	O12^i—Ti2^i—O4^vi	88.7 (2)
O3^i—Rb1—Rb2^iv	54.90 (12)	O12^i—Ti2^i—O11^i	175.5 (2)
O3^i—Rb1—Rb2^iii	77.97 (11)	O12^i—Ti2^i—O8^i	83.4 (4)
O11—Rb1—O12^i	104.90 (14)	O7^ii—Ti2^i—O4^vi	92.7 (2)
O11—Rb1—O5^ii	55.37 (13)	O7^ii—Ti2^i—O11^i	97.2 (2)
O11—Rb1—O6^iii	132.29 (13)	O7^ii—Ti2^i—O8^i	168.8 (4)
O11—Rb1—O7^ii	74.91 (13)	O4^vi—Ti2^i—O11^i	94.5 (2)
O11—Rb1—O8	52.6 (3)	O4^vi—Ti2^i—O8^i	90.1 (2)
O11—Rb1—Rb2^iv	157.25 (10)	O11^i—Ti2^i—O8^i	93.4 (4)
O11—Rb1—Rb2^iii	85.30 (10)	Rb1—As1—O1	63.6 (2)
O12^i—Rb1—O5^ii	103.26 (14)	Rb1—As1—O2	52.90 (19)
O12^i—Rb1—O6^iii	121.66 (14)	Rb1—As1—O3	94.98 (17)
O12^i—Rb1—O7^ii	52.65 (13)	Rb1—As1—O4	153.85 (17)
O12^i—Rb1—O8	88.79 (18)	O1—As1—O2	107.9 (3)
O12^i—Rb1—Rb2^iv	53.84 (10)	O1—As1—O3	112.8 (3)
O12^i—Rb1—Rb2^iii	133.29 (11)	O1—As1—O4	112.0 (3)
O5^ii—Rb1—O6^iii	116.84 (14)	O2—As1—O3	103.6 (3)
O5^ii—Rb1—O7^ii	50.61 (13)	O2—As1—O4	110.6 (3)
O5^ii—Rb1—O8	107.6 (3)	O3—As1—O4	109.6 (2)
O5^ii—Rb1—Rb2^iv	131.28 (10)	Rb2—As2^ii—O5^ii	85.32 (18)
O5^ii—Rb1—Rb2^iii	45.88 (10)	Rb2—As2^ii—O7^ii	57.51 (18)
O6^iii—Rb1—O7^ii	141.79 (13)	Rb2—As2^ii—O6^ii	162.87 (18)
O6^iii—Rb1—O8	114.7 (2)	Rb2—As2^ii—O8^ii	63.3 (4)
O6^iii—Rb1—Rb2^iv	67.84 (9)	O5^ii—As2^ii—O7^ii	105.3 (3)
O6^iii—Rb1—Rb2^iii	70.99 (10)	O5^ii—As2^ii—O6^ii	111.6 (3)
O7^ii—Rb1—O8	103.3 (2)	O5^ii—As2^ii—O8^ii	112.1 (3)
O7^ii—Rb1—Rb2^iv	94.05 (9)	O7^ii—As2^ii—O6^ii	112.7 (3)
O7^ii—Rb1—Rb2^iii	88.63 (10)	O7^ii—As2^ii—O8^ii	104.5 (4)
O8—Rb1—Rb2^iv	113.3 (3)	O6^ii—As2^ii—O8^ii	110.3 (4)
O8—Rb1—Rb2^iii	129.3 (2)	Rb1—O1—Ti1	96.5 (2)
Rb2^iv—Rb1—Rb2^iii	114.75 (3)	Rb1—O1—As1	88.3 (2)
Rb1—Rb2—As2^ii	54.15 (3)	Rb1—O1—Rb2^iii	86.85 (16)
Rb1—Rb2—O4^v	78.03 (9)	Ti1—O1—As1	129.5 (3)
Rb1—Rb2—O11	45.21 (11)	Ti1—O1—Rb2^iii	100.7 (2)
Rb1—Rb2—O7^ii	45.89 (10)	As1—O1—Rb2^iii	129.8 (3)
Rb1—Rb2—Rb1^ix	118.98 (3)	Rb1—O2—As1	98.2 (2)
Rb1—Rb2—O3^ii	127.63 (9)	Rb1—O2—Ti1^x	122.1 (3)
Rb1—Rb2—O12^ii	80.30 (10)	Rb1—O2—Rb2^xi	106.75 (17)
Rb1—Rb2—O2^ii	135.24 (11)	As1—O2—Ti1^x	129.6 (3)
Rb1—Rb2—O8^ii	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—O3^i—Ti2^i	103.6 (2)
Rb1—Rb2—O5^vii	147.63 (10)	Rb1—O3^i—As1^i	128.2 (2)
As2^ii—Rb2—O4^v	128.24 (9)	Rb1—O3^i—Rb2^iv	79.76 (14)
As2^ii—Rb2—O11	75.57 (11)	Ti2^i—O3^i—As1^i	127.6 (3)
As2^ii—Rb2—O7^ii	28.76 (10)	Ti2^i—O3^i—Rb2^iv	97.7 (2)
As2^ii—Rb2—Rb1^ix	105.37 (4)	As1^i—O3^i—Rb2^iv	98.7 (2)
As2^ii—Rb2—O3^ii	80.12 (9)	Rb2—O4^v—Ti2	98.32 (18)
As2^ii—Rb2—O12^ii	58.56 (10)	Rb2—O4^v—As1^v	126.1 (2)
As2^ii—Rb2—O2^ii	86.66 (11)	Ti2—O4^v—As1^v	131.7 (3)
As2^ii—Rb2—O8^ii	28.0 (2)	Rb1—O11—Rb2	95.86 (15)
As2^ii—Rb2—Rb1^vi	133.53 (3)	Rb1—O11—Ti1	95.7 (2)
As2^ii—Rb2—O1^vi	93.52 (12)	Rb1—O11—Ti2	99.4 (2)
As2^ii—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—O7^ii	122.21 (14)	Ti1—O11—Ti2	142.5 (3)
O4^v—Rb2—Rb1^ix	79.37 (10)	Rb1—O12^i—Ti2^i	96.01 (19)
O4^v—Rb2—O3^ii	124.48 (14)	Rb1—O12^i—Rb2^iv	77.59 (13)
O4^v—Rb2—O12^ii	98.57 (14)	Rb1—O12^i—Ti1^iv	124.3 (3)
O4^v—Rb2—O2^ii	144.97 (14)	Ti2^i—O12^i—Rb2^iv	96.3 (2)
O4^v—Rb2—O8^ii	146.26 (14)	Ti2^i—O12^i—Ti1^iv	139.1 (3)
O4^v—Rb2—Rb1^vi	67.41 (9)	Rb2^iv—O12^i—Ti1^iv	98.5 (2)
O4^v—Rb2—O1^vi	116.93 (15)	Rb1—O5^ii—Ti1	101.92 (19)
O4^v—Rb2—O5^vii	91.23 (13)	Rb1—O5^ii—As2^ii	105.2 (2)
O11—Rb2—O7^ii	85.16 (15)	Rb1—O5^ii—Rb2^iii	86.44 (14)
O11—Rb2—Rb1^ix	75.58 (11)	Ti1—O5^ii—As2^ii	130.4 (3)
O11—Rb2—O3^ii	104.87 (14)	Ti1—O5^ii—Rb2^iii	97.77 (19)
O11—Rb2—O12^ii	54.37 (14)	As2^ii—O5^ii—Rb2^iii	124.4 (2)
O11—Rb2—O2^ii	152.23 (15)	Rb1—O6^iii—Ti1^x	97.83 (19)
O11—Rb2—O8^ii	91.38 (16)	Rb1—O6^iii—As2^iii	128.5 (2)
O11—Rb2—Rb1^vi	116.07 (11)	Ti1^x—O6^iii—As2^iii	133.4 (3)
O11—Rb2—O1^vi	145.63 (16)	Rb1—O7^ii—Rb2	93.21 (14)
O11—Rb2—O5^vii	144.64 (15)	Rb1—O7^ii—Ti2^i	89.18 (17)
O7^ii—Rb2—Rb1^ix	134.07 (10)	Rb1—O7^ii—As2^ii	93.8 (2)
O7^ii—Rb2—O3^ii	103.75 (13)	Rb2—O7^ii—Ti2^i	140.1 (3)
O7^ii—Rb2—O12^ii	86.35 (14)	Rb2—O7^ii—As2^ii	93.7 (2)
O7^ii—Rb2—O2^ii	89.37 (15)	Ti2^i—O7^ii—As2^ii	125.9 (3)
O7^ii—Rb2—O8^ii	51.2 (2)	Rb1—O8—Ti2	109.3 (6)
O7^ii—Rb2—Rb1^vi	104.87 (10)	Rb1—O8—Rb2^xi	104.7 (2)
O7^ii—Rb2—O1^vi	71.77 (16)	Rb1—O8—As2	114.3 (4)
O7^ii—Rb2—O5^vii	126.83 (15)	Ti2—O8—Rb2^xi	99.0 (2)
Rb1^ix—Rb2—O3^ii	45.33 (9)	Ti2—O8—As2	132.0 (3)
Rb1^ix—Rb2—O12^ii	48.56 (10)	Rb2^xi—O8—As2	88.7 (6)

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.