Nonapotassium trialuminium hexa­phosphate

Liu, Z.; Zhang, G.; Zhang, J.; Fu, P.; Wu, Y.

doi:10.1107/S160053681001305X

inorganic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 66| Part 5| May 2010| Pages i37-i38

https://doi.org/10.1107/S160053681001305X

Open

access

Nonapotassium trialuminium hexaphosphate

Zuoliang Liu,^a ‡ Guochun Zhang,^a ^* Jianxiu Zhang,^a Peizhen Fu ^a and Yicheng Wu ^a

^aKey Laboratory of Functional Crystal and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
^*Correspondence e-mail: bccrd@mail.ipc.ac.cn

(Received 21 January 2010; accepted 8 April 2010; online 17 April 2010)

In the title compound, K₉Al₃(PO₄)₆, the anionic substructure is built of interlinked [PO₄] and [AlO₄] tetrahedra. Each O atom of the [AlO₄] tetrahedron is common to a positionally different [PO₄] tetrahedron; thus, each [AlO₄] tetrahedron is surrounded by four positionally different [PO₄] tetrahedra. On the other hand, each [PO₄] tetrahedron shares its two O atoms with two positionally different [AlO₄] tetrahedra; the other two phosphate O atoms are terminal ones coordinated by K atoms. The terminal O atoms are usually closer to the K atoms than the bridging O atoms between the [AlO₄] and [PO₄] tetrahedra. There are nine symmetry-independent K atoms in the structure. The coordination numbers of the K atoms are 6 or 7 or 8 up to a distance of 3.31 Å. There are channels in the anionic substructure oriented along the [10 $[\overline{1}]$ ] direction that are filled by K atoms.

Related literature

For applications of metal phosphates, see: Barone & Nancollas (1978 ); Dickinson et al. (1996 ). For non-centrosymmetric phosphates with non-linear optical properties, see: Noor & Dam (1986 ); Aguilo & Wuensdregt (1985 ); Masse & Grenier (1971 ). For the non-centrosymmetric structures of A₃Al₂(PO₄)₃ (A = K, Rb and Tl), which have three-dimensional [Al₂P₃O₁₂]³⁻ frameworks, see: Nandini Devi & Vidyasagar (2000 ). For the structure of KAlP₂O₇, see: Ng & Calvo (1973 );

Experimental

Crystal data

K₉Al₃(PO₄)₆
M_r = 1002.66
Monoclinic, P 2₁ /c
a = 20.289 (4) Å
b = 9.835 (2) Å
c = 13.521 (3) Å
β = 100.56 (3)°
V = 2652.2 (9) Å³
Z = 4
Mo Kα radiation
μ = 2.02 mm⁻¹
T = 113 K
0.26 × 0.20 × 0.18 mm

Data collection

Bruker SMART 1000 diffractometer
Absorption correction: numerical (CrystalClear; Rigaku/MSC, 2005 ) T_min = 0.622, T_max = 0.713
35263 measured reflections
11751 independent reflections
10169 reflections with I > 2σ(I)
R_int = 0.028

Refinement

R[F² > 2σ(F²)] = 0.023
wR(F²) = 0.059
S = 1.10
11751 reflections
380 parameters
Δρ_max = 0.54 e Å⁻³
Δρ_min = −0.52 e Å⁻³

Table 1
Characterization of K—O coordination spheres; coordination number as well as minimal and maximal distances (Å) within the coordination spheres for each K atom are given

Atom K	Coordination number	K—O distances
K1	8	2.6202 (10)–3.2026 (12)
K2	7	2.5994 (9)–2.9721 (10)
K3	6	2.6337 (11)–2.9790 (11)
K4	6	2.7005 (10)–3.0451 (10)
K5	8	2.6787 (9)–3.3087 (12)
K6	7	2.6690 (10)–3.0404 (9)
K7	7	2.6369 (9)–3.0973 (10)
K8	7	2.5736 (9)–3.0747 (10)
K9	7	2.6965 (9)–3.3094 (11)

Table 2
Characterization of K—O coordination spheres; the minimal and maximal K—O distances (Å) for the terminal and bridging O atoms (there is only one bridging oxygen in the coordination spheres of K2, K3, and K8)

Atom K	K—O_terminal / K—O_bridge distances
K1	2.6202 (12)–3.2027 (18) / 3.0287 (14)–3.1684 (16)
K2	2.5994 (12)–2.9722 (14) / 2.8588 (14)
K3	2.6337 (13)–2.9790 (14) / 2.8348 (13)
K4	2.7006 (13)–2.7762 (15) / 2.9576 (15)–3.0451 (13)
K5	2.6787 (11)–3.3088 (19) / 3.1012 (15)–3.2476 (15)
K6	2.6690 (14)–2.9869 (16) / 2.8236 (13)–3.0405 (13)
K7	2.6368 (12)–2.9005 (15) / 2.7891 (14)–3.0974 (13)
K8	2.5737 (12)–3.0747 (13) / 2.9491 (13)
K9	2.6965 (2)–2.8865 (13) / 2.9783 (12)–3.3095 (16)

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006 ); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2005).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S160053681001305X/fb2181sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681001305X/fb2181Isup2.hkl

checkCIF report

Comment top

Various metal phosphates have been widely used due to their good optical and chemical properties. For example, Ca₅(PO₄)₃F has been used in dentistry (Barone & Nancollas, 1978) and Sr₅(PO₄)₃F (Dickinson et al., 1996) has been used as a laser crystal in laser technology. Especially, some non-centrosymmetric phosphates have been used as important crystals with nonlinear optical properties, such as KH₂PO₄ (KDP) (Noor & Dam, 1986), NH₄H₂PO₄ (ADP) (Aguilo & Wuensdregt, 1985) and KTiOPO₄ (KTP) (Masse & Grenier, 1971). Aluminophosphates have attracted much attention because of their diverse structures.

Aluminophosphates contain 1D, 2D or 3D infinite frameworks with varying chemical composition. Nandini Devi & Vidyasagar (2000) reported non-centrosymmetric structures of A₃Al₂(PO₄)₃ (A=K, Rb and Tl). These compounds have 3D [Al₂P₃O₁₂]^3- frameworks. The latter study has inspired us to investigate the A₂O—Al₂O₃—P₂O₅ (A=K, Rb, Cs) system in order to search for new functional materials. As a result of our study a new aluminophosphate, the title structure K₉Al₃(PO₄)₆, has been discovered.

In K₉Al₃(PO₄)₆, all the aluminium and phosphorus atoms adopt the tetrahedral coordination. Each [AlO₄] tetrahedron shares each of its O atoms with a positionally different neighbour [PO₄] tetrahedron, while each [PO₄] tetrahedron shares its two O atoms with two different neighbour [AlO₄] tetrahedral. There are two pairs of chemically different O atoms around the P atoms: The terminal and the bridging oxygens that are involved in P-O-Al connections (Fig. 1). The P-O distance to the bridging oxygens vary in the interval 1.5645 (10) - 1.5881 (8) Å, while the P-O distances to the terminal oxygens are in the interval 1.4993 (10) - 1.5087 (9) Å.

There are channels in the anionic substructure along [1 0 1] (Fig. 2). These channels are filled by K atoms (Fig. 3). The coordination numbers of K atoms are 6 or 7 or 8 up to the distance 3.31 Å (Tab. 1). The terminal phosphate oxygens tend to be closer to K atoms than the bridging ones (Tab. 2).

Related literature top

For related literature, see: Nandini Devi & Vidyasagar (2000); Ng & Calvo (1973).

For related literature, see: Aguilo & Wuensdregt (1985); Barone & Nancollas (1978); Dickinson et al. (1996); Masse & Grenier (1971); Noor & Dam (1986).

Experimental top

Single crystals of K₉Al₃(PO₄)₆ have been obtained by the high temperature solution method in a electric resistance furnace. Starting materials of the analytical grade KH₂PO₄ (136.15 g) and K₂CO₃ (69.03 g), high purity Al₂O₃ (51.08 g) and KF (58.33 g), in the respective molar ratio 2:1:1:2, were mixed and melt in a platinum crucible with a diameter of 60 mm and a height of 60 mm at 1273 K. The solution was stirred with a platinum plate for 24 hours. After the solution had been cooled to 1123 K at a rate of 10 Kh^-1, a platinum wire attached to an alumina shaft was slowly dipped into the solution, which was then followed by a slow cooling at the rate of 0.5 Kh^-1. Thus, a few colourless, transparent plate K₉Al₃(PO₄)₆ crystals with typical size of 3 × 3 × 0.5 mm crystallized on the platinum wire. After one week, the crystals were drawn out from the solution at 1050 K and cooled down to room temperature at the rate of 10 Kh^-1.

Structure description top

For related literature, see: Nandini Devi & Vidyasagar (2000); Ng & Calvo (1973).

For related literature, see: Aguilo & Wuensdregt (1985); Barone & Nancollas (1978); Dickinson et al. (1996); Masse & Grenier (1971); Noor & Dam (1986).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalClear (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2005).

Figures top

	Fig. 1. Unit cell of K₉Al₃(PO₄)₆. The displacement ellipsoids are drawn at the 90% probability level.
	Fig. 2. Anionic framework of K₉Al₃(PO₄)_6, viewed along [1 0 1].
	Fig. 3. Anionic framework of K₉Al₃(PO₄)₆filled with K atoms, viewed along [101].

Nonapotassium trialuminium hexaphosphate top

Crystal data top

K₉Al₃(PO₄)₆	F(000) = 1968
M_r = 1002.66	D_x = 2.511 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 11243 reflections
a = 20.289 (4) Å	θ = 1.5–36.1°
b = 9.835 (2) Å	µ = 2.02 mm⁻¹
c = 13.521 (3) Å	T = 113 K
β = 100.56 (3)°	Block, colorless
V = 2652.2 (9) Å³	0.26 × 0.20 × 0.18 mm
Z = 4

Data collection top

Bruker SMART 1000 diffractometer	11751 independent reflections
Radiation source: rotating anode	10169 reflections with I > 2σ(I)
Confocal monochromator	R_int = 0.028
Detector resolution: 7.31 pixels mm^-1	θ_max = 36.4°, θ_min = 2.0°
ω and φ scans	h = −32→32
Absorption correction: numerical (CrystalClear; Rigaku/MSC, 2005)	k = −15→14
T_min = 0.622, T_max = 0.713	l = −21→21
35263 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.023	w = 1/[σ²(F_o²) + (0.0289P)² + 0.2004P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.059	(Δ/σ)_max = 0.002
S = 1.10	Δρ_max = 0.54 e Å⁻³
11751 reflections	Δρ_min = −0.52 e Å⁻³
380 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0094 (3)
0 constraints

Crystal data top

K₉Al₃(PO₄)₆	V = 2652.2 (9) Å³
M_r = 1002.66	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 20.289 (4) Å	µ = 2.02 mm⁻¹
b = 9.835 (2) Å	T = 113 K
c = 13.521 (3) Å	0.26 × 0.20 × 0.18 mm
β = 100.56 (3)°

Data collection top

Bruker SMART 1000 diffractometer	11751 independent reflections
Absorption correction: numerical (CrystalClear; Rigaku/MSC, 2005)	10169 reflections with I > 2σ(I)
T_min = 0.622, T_max = 0.713	R_int = 0.028
35263 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.023	380 parameters
wR(F²) = 0.059	0 restraints
S = 1.10	Δρ_max = 0.54 e Å⁻³
11751 reflections	Δρ_min = −0.52 e Å⁻³

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
P1	0.298252 (13)	0.34947 (3)	0.33480 (2)	0.00581 (5)
P2	0.533853 (13)	0.58644 (3)	0.36009 (2)	0.00594 (5)
P3	0.187195 (13)	0.57954 (3)	0.69175 (2)	0.00569 (5)
P4	−0.043493 (13)	0.14690 (3)	0.10689 (2)	0.00566 (5)
P5	0.356473 (13)	0.65268 (3)	0.99111 (2)	0.00556 (5)
P6	0.134551 (13)	0.14154 (3)	0.50989 (2)	0.00546 (5)
Al1	0.089399 (16)	0.07540 (3)	0.02839 (2)	0.00532 (6)
Al2	0.248584 (16)	0.06371 (3)	0.38928 (2)	0.00494 (6)
Al3	0.404521 (16)	0.56335 (3)	0.44487 (2)	0.00506 (6)
O1	0.30136 (4)	0.20134 (8)	0.37989 (6)	0.01040 (14)
O2	0.30827 (5)	0.34641 (8)	0.22768 (6)	0.01385 (16)
O3	0.23519 (4)	0.41939 (8)	0.35084 (7)	0.01469 (16)
O4	0.36066 (5)	0.41798 (8)	0.40128 (7)	0.01553 (18)
O5	0.57090 (4)	0.71131 (8)	0.40329 (6)	0.01132 (15)
O6	0.54290 (4)	0.54825 (8)	0.25534 (6)	0.00961 (14)
O7	0.45662 (4)	0.60301 (9)	0.35924 (6)	0.01063 (14)
O8	0.55470 (4)	0.45990 (7)	0.43131 (6)	0.00885 (14)
O9	0.24384 (4)	0.56940 (8)	0.63432 (6)	0.01142 (15)
O10	0.11777 (4)	0.54245 (7)	0.62321 (6)	0.00823 (14)
O11	0.17814 (4)	0.71622 (8)	0.73771 (6)	0.01017 (14)
O12	0.19385 (4)	0.46544 (8)	0.77559 (6)	0.00888 (14)
O13	−0.09231 (4)	0.25724 (7)	0.06586 (6)	0.00840 (13)
O14	0.01158 (4)	0.14074 (7)	0.03954 (6)	0.00818 (14)
O15	−0.07987 (4)	0.00350 (7)	0.09080 (6)	0.00757 (13)
O16	−0.01117 (4)	0.16378 (8)	0.21565 (6)	0.01014 (14)
O17	0.34118 (4)	0.65873 (8)	1.09580 (6)	0.01213 (15)
O18	0.35063 (4)	0.79852 (7)	0.94185 (6)	0.00881 (14)
O19	0.42285 (4)	0.58847 (8)	0.98471 (7)	0.01214 (15)
O20	0.29847 (4)	0.57812 (8)	0.91867 (6)	0.01111 (15)
O21	0.20437 (4)	0.09364 (8)	0.48639 (6)	0.00835 (13)
O22	0.11949 (4)	0.05905 (7)	0.59700 (6)	0.00888 (14)
O23	0.14854 (4)	0.29353 (7)	0.54464 (6)	0.00891 (14)
O24	0.08212 (4)	0.14116 (8)	0.41564 (6)	0.01017 (14)
K1	0.287854 (12)	0.17131 (2)	0.079146 (18)	0.00949 (4)
K2	0.420108 (12)	0.44811 (2)	0.178588 (19)	0.01038 (4)
K3	0.233669 (12)	0.57239 (2)	0.160286 (19)	0.01005 (4)
K4	0.551481 (12)	0.66477 (2)	0.075535 (18)	0.00984 (4)
K5	0.370503 (13)	0.84243 (2)	0.243608 (19)	0.01203 (5)
K6	0.054431 (12)	0.67635 (2)	0.106782 (18)	0.00886 (4)
K7	0.213027 (11)	0.66267 (2)	0.427477 (18)	0.00950 (4)
K8	0.058558 (12)	0.93957 (2)	0.292875 (18)	0.01007 (4)
K9	0.116931 (12)	0.29859 (2)	0.266699 (19)	0.01164 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P1	0.00581 (11)	0.00550 (10)	0.00599 (12)	−0.00069 (8)	0.00070 (9)	−0.00048 (8)
P2	0.00578 (11)	0.00678 (10)	0.00535 (11)	0.00080 (8)	0.00123 (9)	0.00050 (8)
P3	0.00625 (11)	0.00554 (10)	0.00511 (11)	−0.00021 (8)	0.00058 (9)	0.00017 (8)
P4	0.00518 (11)	0.00625 (10)	0.00552 (11)	−0.00004 (8)	0.00088 (8)	−0.00072 (8)
P5	0.00535 (11)	0.00497 (10)	0.00632 (12)	−0.00068 (8)	0.00096 (9)	−0.00019 (8)
P6	0.00536 (11)	0.00549 (10)	0.00549 (11)	0.00029 (8)	0.00088 (8)	0.00015 (8)
Al1	0.00504 (13)	0.00500 (12)	0.00582 (14)	−0.00004 (9)	0.00069 (11)	−0.00028 (10)
Al2	0.00504 (13)	0.00437 (12)	0.00522 (14)	0.00060 (9)	0.00042 (10)	−0.00012 (10)
Al3	0.00478 (13)	0.00426 (12)	0.00582 (14)	0.00029 (9)	0.00011 (10)	−0.00015 (10)
O1	0.0108 (3)	0.0065 (3)	0.0133 (4)	−0.0026 (2)	0.0007 (3)	0.0015 (3)
O2	0.0213 (4)	0.0131 (4)	0.0086 (4)	0.0002 (3)	0.0065 (3)	0.0005 (3)
O3	0.0110 (4)	0.0129 (4)	0.0217 (5)	0.0031 (3)	0.0072 (3)	−0.0006 (3)
O4	0.0157 (4)	0.0068 (3)	0.0195 (4)	−0.0029 (3)	−0.0091 (3)	0.0002 (3)
O5	0.0147 (4)	0.0073 (3)	0.0115 (4)	−0.0024 (3)	0.0013 (3)	0.0000 (3)
O6	0.0100 (3)	0.0133 (3)	0.0060 (3)	0.0015 (3)	0.0026 (3)	−0.0003 (3)
O7	0.0071 (3)	0.0172 (4)	0.0079 (4)	0.0033 (3)	0.0023 (3)	0.0021 (3)
O8	0.0114 (3)	0.0071 (3)	0.0071 (3)	0.0011 (2)	−0.0006 (3)	0.0011 (3)
O9	0.0096 (3)	0.0145 (4)	0.0112 (4)	−0.0004 (3)	0.0045 (3)	−0.0001 (3)
O10	0.0077 (3)	0.0085 (3)	0.0073 (3)	0.0005 (2)	−0.0018 (3)	−0.0011 (3)
O11	0.0130 (4)	0.0069 (3)	0.0100 (4)	0.0001 (3)	0.0004 (3)	−0.0022 (3)
O12	0.0094 (3)	0.0087 (3)	0.0073 (3)	−0.0019 (2)	−0.0016 (3)	0.0030 (3)
O13	0.0081 (3)	0.0079 (3)	0.0094 (3)	0.0018 (2)	0.0020 (3)	0.0008 (3)
O14	0.0064 (3)	0.0083 (3)	0.0108 (4)	0.0005 (2)	0.0042 (3)	0.0004 (3)
O15	0.0091 (3)	0.0068 (3)	0.0072 (3)	−0.0023 (2)	0.0026 (3)	−0.0008 (2)
O16	0.0112 (4)	0.0116 (3)	0.0069 (4)	0.0002 (3)	−0.0004 (3)	−0.0022 (3)
O17	0.0165 (4)	0.0117 (3)	0.0093 (4)	−0.0007 (3)	0.0054 (3)	0.0000 (3)
O18	0.0083 (3)	0.0057 (3)	0.0119 (4)	−0.0020 (2)	0.0005 (3)	0.0018 (3)
O19	0.0080 (3)	0.0113 (3)	0.0175 (4)	0.0025 (3)	0.0033 (3)	0.0004 (3)
O20	0.0107 (3)	0.0078 (3)	0.0130 (4)	−0.0045 (3)	−0.0027 (3)	0.0008 (3)
O21	0.0077 (3)	0.0107 (3)	0.0070 (3)	0.0023 (2)	0.0022 (3)	0.0001 (3)
O22	0.0101 (3)	0.0092 (3)	0.0078 (3)	−0.0004 (2)	0.0028 (3)	0.0015 (3)
O23	0.0072 (3)	0.0051 (3)	0.0139 (4)	0.0009 (2)	0.0006 (3)	−0.0007 (3)
O24	0.0083 (3)	0.0133 (3)	0.0079 (4)	0.0006 (3)	−0.0011 (3)	−0.0007 (3)
K1	0.00909 (9)	0.00962 (9)	0.00989 (10)	−0.00004 (7)	0.00210 (8)	0.00004 (7)
K2	0.01006 (9)	0.00876 (9)	0.01141 (11)	−0.00028 (7)	−0.00044 (8)	−0.00135 (8)
K3	0.00859 (9)	0.00980 (9)	0.01165 (11)	−0.00057 (7)	0.00156 (8)	−0.00163 (8)
K4	0.01018 (9)	0.01036 (9)	0.00913 (10)	−0.00115 (7)	0.00219 (8)	0.00072 (7)
K5	0.01415 (11)	0.01086 (10)	0.01155 (11)	−0.00281 (7)	0.00362 (8)	−0.00148 (8)
K6	0.00872 (9)	0.00997 (9)	0.00819 (10)	0.00093 (7)	0.00236 (7)	0.00127 (7)
K7	0.00723 (9)	0.01039 (9)	0.01103 (10)	0.00059 (7)	0.00207 (8)	0.00037 (7)
K8	0.01277 (10)	0.00765 (9)	0.01026 (10)	0.00019 (7)	0.00335 (8)	0.00097 (7)
K9	0.01126 (10)	0.01316 (10)	0.01026 (10)	−0.00163 (7)	0.00134 (8)	0.00316 (8)

Geometric parameters (Å, º) top

P1—O2	1.4993 (10)	O16—K6^ix	2.7060 (11)
P1—O3	1.5030 (9)	O16—K8^xi	2.7225 (10)
P1—O4	1.5645 (10)	O16—K8^ix	2.8730 (10)
P1—O1	1.5760 (8)	O16—K9	2.8864 (10)
P2—O5	1.5011 (9)	O17—K3^xii	2.6337 (11)
P2—O6	1.5087 (9)	O17—K5^xii	2.6788 (10)
P2—O7	1.5734 (9)	O17—K2^xii	2.7296 (10)
P2—O8	1.5829 (8)	O18—Al3^viii	1.7396 (8)
P3—O9	1.5036 (10)	O18—K7^viii	2.7891 (10)
P3—O11	1.5062 (8)	O18—K5^viii	3.1088 (10)
P3—O10	1.5803 (9)	O19—K4^iv	2.7005 (10)
P3—O12	1.5831 (8)	O19—K4^xii	2.7761 (11)
P4—O13	1.5049 (8)	O19—K2^xii	2.9721 (10)
P4—O16	1.5056 (9)	O19—K5^viii	3.3087 (12)
P4—O14	1.5667 (9)	O20—Al2^vi	1.7264 (8)
P4—O15	1.5881 (8)	O20—K7^viii	3.0973 (10)
P5—O19	1.5043 (9)	O20—K5^viii	3.1013 (12)
P5—O17	1.5049 (9)	O21—K3^vi	2.8347 (9)
P5—O20	1.5682 (9)	O21—K1^vi	3.0012 (10)
P5—O18	1.5767 (8)	O22—K3^vi	2.6539 (10)
P6—O24	1.5029 (10)	O22—K6^vi	2.6802 (9)
P6—O22	1.5068 (9)	O22—K9^vi	2.6965 (9)
P6—O23	1.5770 (8)	O23—Al1^vi	1.7472 (8)
P6—O21	1.5794 (9)	O23—K1^vi	2.8007 (10)
Al1—O14	1.7366 (9)	O23—K9^vi	3.3094 (11)
Al1—O10ⁱ	1.7457 (9)	O24—K8^xi	2.5736 (9)
Al1—O23ⁱ	1.7472 (8)	O24—K9	2.7337 (10)
Al1—O15ⁱⁱ	1.7671 (9)	O24—K6^ix	2.7531 (10)
Al2—O20ⁱ	1.7264 (8)	K1—O9ⁱ	2.6837 (10)
Al2—O1	1.7449 (9)	K1—O23ⁱ	2.8007 (10)
Al2—O21	1.7457 (10)	K1—O5^v	2.8591 (11)
Al2—O12ⁱ	1.7472 (10)	K1—O21ⁱ	3.0012 (10)
Al3—O4	1.7295 (9)	K1—O1ⁱ	3.0286 (10)
Al3—O18ⁱⁱⁱ	1.7396 (8)	K1—O4ⁱ	3.1684 (13)
Al3—O8^iv	1.7411 (10)	K1—O3ⁱ	3.2026 (12)
Al3—O7	1.7490 (10)	K2—O5^v	2.5994 (9)
O1—K4^v	2.9576 (11)	K2—O17^xiii	2.7296 (10)
O1—K1^vi	3.0286 (10)	K2—O19^xiii	2.9721 (10)
O2—K1	2.6202 (10)	K3—O17^xiii	2.6337 (11)
O2—K2	2.6725 (11)	K3—O22ⁱ	2.6539 (10)
O2—K3	2.7486 (10)	K3—O11ⁱⁱⁱ	2.6683 (9)
O3—K7	2.6779 (10)	K3—O21ⁱ	2.8347 (9)
O3—K9	2.7316 (11)	K4—O19^iv	2.7005 (10)
O3—K3	2.9790 (11)	K4—O5ⁱⁱⁱ	2.7205 (10)
O3—K1^vi	3.2026 (12)	K4—O19^xiii	2.7761 (11)
O4—K4^v	3.0451 (10)	K4—O1^vii	2.9576 (11)
O4—K1^vi	3.1684 (13)	K4—O4^vii	3.0451 (10)
O5—K2^vii	2.5994 (9)	K5—O6^vii	2.6787 (9)
O5—K4^viii	2.7205 (10)	K5—O17^xiii	2.6788 (10)
O5—K1^vii	2.8591 (11)	K5—O9ⁱⁱⁱ	2.8544 (12)
O6—K5^v	2.6787 (9)	K5—O20ⁱⁱⁱ	3.1013 (12)
O6—K2	2.7029 (11)	K5—O18ⁱⁱⁱ	3.1088 (10)
O6—K4	2.7219 (9)	K5—O8^vii	3.2476 (11)
O7—K2	2.8587 (10)	K5—O19ⁱⁱⁱ	3.3087 (12)
O7—K5	3.1685 (10)	K6—O13^x	2.6690 (10)
O8—Al3^iv	1.7411 (10)	K6—O22ⁱ	2.6803 (9)
O8—K5^v	3.2476 (11)	K6—O16^xiv	2.7060 (11)
O9—K1^vi	2.6837 (10)	K6—O24^xiv	2.7531 (10)
O9—K5^viii	2.8544 (12)	K6—O14^x	2.8235 (10)
O9—K7	2.9005 (11)	K6—O11ⁱⁱⁱ	2.9867 (12)
O10—Al1^vi	1.7457 (9)	K6—O10ⁱⁱⁱ	3.0404 (9)
O10—K8^viii	2.7834 (11)	K7—O13^xiv	2.6369 (9)
O10—K6^viii	3.0404 (9)	K7—O18ⁱⁱⁱ	2.7891 (10)
O11—K3^viii	2.6683 (9)	K7—O11ⁱⁱⁱ	2.7995 (10)
O11—K7^viii	2.7995 (10)	K7—O15^xiv	3.0928 (10)
O11—K6^viii	2.9867 (12)	K7—O20ⁱⁱⁱ	3.0973 (10)
O11—K8^viii	3.0747 (10)	K8—O24^xv	2.5736 (9)
O12—Al2^vi	1.7472 (10)	K8—O13^xiv	2.6179 (9)
O12—K8^viii	2.9492 (10)	K8—O16^xv	2.7225 (10)
O12—K9^vi	3.0206 (9)	K8—O10ⁱⁱⁱ	2.7834 (11)
O13—K8^ix	2.6179 (9)	K8—O16^xiv	2.8730 (10)
O13—K7^ix	2.6369 (9)	K8—O12ⁱⁱⁱ	2.9492 (10)
O13—K6^x	2.6690 (10)	K8—O11ⁱⁱⁱ	3.0747 (10)
O14—K6^x	2.8235 (10)	K9—O22ⁱ	2.6965 (9)
O15—Al1ⁱⁱ	1.7671 (9)	K9—O15^xiv	2.9782 (9)
O15—K9^ix	2.9782 (9)	K9—O12ⁱ	3.0206 (9)
O15—K7^ix	3.0928 (10)	K9—O23ⁱ	3.3094 (11)

O2—P1—O3	114.74 (6)	O6—K4—O1^vii	95.55 (4)
O2—P1—O4	108.96 (6)	O19^xiii—K4—O1^vii	162.75 (3)
O3—P1—O4	109.93 (5)	O19^iv—K4—O4^vii	130.06 (3)
O2—P1—O1	110.62 (5)	O5ⁱⁱⁱ—K4—O4^vii	63.12 (3)
O3—P1—O1	109.99 (5)	O6—K4—O4^vii	112.61 (3)
O4—P1—O1	101.83 (5)	O19^xiii—K4—O4^vii	138.74 (2)
O5—P2—O6	115.50 (5)	O1^vii—K4—O4^vii	47.89 (2)
O5—P2—O7	110.19 (5)	O6^vii—K5—O17^xiii	124.71 (3)
O6—P2—O7	108.14 (5)	O6^vii—K5—O9ⁱⁱⁱ	107.49 (3)
O5—P2—O8	110.34 (5)	O17^xiii—K5—O9ⁱⁱⁱ	76.28 (3)
O6—P2—O8	108.08 (5)	O6^vii—K5—O20ⁱⁱⁱ	101.89 (3)
O7—P2—O8	103.92 (5)	O17^xiii—K5—O20ⁱⁱⁱ	131.91 (3)
O9—P3—O11	115.78 (5)	O9ⁱⁱⁱ—K5—O20ⁱⁱⁱ	79.22 (3)
O9—P3—O10	111.44 (5)	O6^vii—K5—O18ⁱⁱⁱ	121.40 (3)
O11—P3—O10	106.55 (4)	O17^xiii—K5—O18ⁱⁱⁱ	107.24 (3)
O9—P3—O12	110.48 (5)	O9ⁱⁱⁱ—K5—O18ⁱⁱⁱ	109.57 (3)
O11—P3—O12	109.75 (5)	O20ⁱⁱⁱ—K5—O18ⁱⁱⁱ	45.61 (2)
O10—P3—O12	101.90 (5)	O6^vii—K5—O7	104.90 (3)
O13—P4—O16	114.83 (5)	O17^xiii—K5—O7	83.91 (3)
O13—P4—O14	107.75 (5)	O9ⁱⁱⁱ—K5—O7	147.55 (2)
O16—P4—O14	110.03 (5)	O20ⁱⁱⁱ—K5—O7	96.03 (2)
O13—P4—O15	109.38 (5)	O18ⁱⁱⁱ—K5—O7	52.43 (2)
O16—P4—O15	109.88 (5)	O6^vii—K5—O8^vii	48.81 (2)
O14—P4—O15	104.43 (4)	O17^xiii—K5—O8^vii	76.48 (3)
O19—P5—O17	114.32 (6)	O9ⁱⁱⁱ—K5—O8^vii	90.66 (3)
O19—P5—O20	110.19 (5)	O20ⁱⁱⁱ—K5—O8^vii	144.56 (2)
O17—P5—O20	110.20 (5)	O18ⁱⁱⁱ—K5—O8^vii	159.77 (2)
O19—P5—O18	110.88 (5)	O7—K5—O8^vii	109.55 (3)
O17—P5—O18	110.42 (5)	O6^vii—K5—O19ⁱⁱⁱ	75.39 (3)
O20—P5—O18	99.89 (5)	O17^xiii—K5—O19ⁱⁱⁱ	149.41 (2)
O24—P6—O22	116.61 (5)	O9ⁱⁱⁱ—K5—O19ⁱⁱⁱ	122.93 (3)
O24—P6—O23	108.41 (4)	O20ⁱⁱⁱ—K5—O19ⁱⁱⁱ	46.16 (2)
O22—P6—O23	109.19 (5)	O18ⁱⁱⁱ—K5—O19ⁱⁱⁱ	46.45 (2)
O24—P6—O21	110.50 (5)	O7—K5—O19ⁱⁱⁱ	67.55 (3)
O22—P6—O21	108.33 (5)	O8^vii—K5—O19ⁱⁱⁱ	122.41 (2)
O23—P6—O21	102.92 (4)	O13^x—K6—O22ⁱ	86.84 (3)
O14—Al1—O10ⁱ	111.38 (5)	O13^x—K6—O16^xiv	168.34 (2)
O14—Al1—O23ⁱ	109.29 (4)	O22ⁱ—K6—O16^xiv	104.31 (3)
O10ⁱ—Al1—O23ⁱ	105.73 (4)	O13^x—K6—O24^xiv	112.32 (4)
O14—Al1—O15ⁱⁱ	107.00 (5)	O22ⁱ—K6—O24^xiv	112.38 (3)
O10ⁱ—Al1—O15ⁱⁱ	110.15 (4)	O16^xiv—K6—O24^xiv	66.94 (4)
O23ⁱ—Al1—O15ⁱⁱ	113.35 (5)	O13^x—K6—O14^x	53.63 (3)
O20ⁱ—Al2—O1	107.57 (5)	O22ⁱ—K6—O14^x	133.66 (3)
O20ⁱ—Al2—O21	108.87 (4)	O16^xiv—K6—O14^x	117.48 (3)
O1—Al2—O21	109.31 (4)	O24^xiv—K6—O14^x	70.39 (3)
O20ⁱ—Al2—O12ⁱ	108.74 (4)	O13^x—K6—O11ⁱⁱⁱ	94.96 (3)
O1—Al2—O12ⁱ	111.28 (4)	O22ⁱ—K6—O11ⁱⁱⁱ	88.10 (3)
O21—Al2—O12ⁱ	110.98 (4)	O16^xiv—K6—O11ⁱⁱⁱ	82.20 (3)
O4—Al3—O18ⁱⁱⁱ	110.83 (5)	O24^xiv—K6—O11ⁱⁱⁱ	146.01 (3)
O4—Al3—O8^iv	110.07 (4)	O14^x—K6—O11ⁱⁱⁱ	115.41 (3)
O18ⁱⁱⁱ—Al3—O8^iv	108.12 (4)	O13^x—K6—O10ⁱⁱⁱ	69.86 (2)
O4—Al3—O7	107.13 (5)	O22ⁱ—K6—O10ⁱⁱⁱ	125.73 (3)
O18ⁱⁱⁱ—Al3—O7	105.30 (4)	O16^xiv—K6—O10ⁱⁱⁱ	100.27 (3)
O8^iv—Al3—O7	115.31 (4)	O24^xiv—K6—O10ⁱⁱⁱ	121.72 (2)
O2—K1—O9ⁱ	112.37 (3)	O14^x—K6—O10ⁱⁱⁱ	67.14 (3)
O2—K1—O23ⁱ	93.41 (4)	O11ⁱⁱⁱ—K6—O10ⁱⁱⁱ	48.47 (2)
O9ⁱ—K1—O23ⁱ	77.18 (3)	O13^xiv—K7—O3	123.45 (3)
O2—K1—O5^v	80.25 (4)	O13^xiv—K7—O18ⁱⁱⁱ	150.88 (2)
O9ⁱ—K1—O5^v	118.54 (3)	O3—K7—O18ⁱⁱⁱ	84.97 (3)
O23ⁱ—K1—O5^v	164.26 (2)	O13^xiv—K7—O11ⁱⁱⁱ	78.51 (4)
O2—K1—O21ⁱ	79.16 (3)	O3—K7—O11ⁱⁱⁱ	93.31 (3)
O9ⁱ—K1—O21ⁱ	127.19 (3)	O18ⁱⁱⁱ—K7—O11ⁱⁱⁱ	95.01 (4)
O23ⁱ—K1—O21ⁱ	50.22 (2)	O13^xiv—K7—O9	96.66 (4)
O5^v—K1—O21ⁱ	114.15 (3)	O3—K7—O9	93.94 (3)
O2—K1—O1ⁱ	112.50 (3)	O18ⁱⁱⁱ—K7—O9	86.56 (4)
O9ⁱ—K1—O1ⁱ	134.51 (3)	O11ⁱⁱⁱ—K7—O9	172.69 (2)
O23ⁱ—K1—O1ⁱ	93.09 (4)	O13^xiv—K7—O15^xiv	51.54 (2)
O5^v—K1—O1ⁱ	76.36 (4)	O3—K7—O15^xiv	73.92 (3)
O21ⁱ—K1—O1ⁱ	56.35 (3)	O18ⁱⁱⁱ—K7—O15^xiv	157.43 (2)
O2—K1—O4ⁱ	137.20 (3)	O11ⁱⁱⁱ—K7—O15^xiv	94.11 (3)
O9ⁱ—K1—O4ⁱ	101.05 (3)	O9—K7—O15^xiv	87.00 (3)
O23ⁱ—K1—O4ⁱ	120.30 (3)	O13^xiv—K7—O20ⁱⁱⁱ	103.94 (3)
O5^v—K1—O4ⁱ	60.10 (3)	O3—K7—O20ⁱⁱⁱ	125.85 (3)
O21ⁱ—K1—O4ⁱ	101.67 (3)	O18ⁱⁱⁱ—K7—O20ⁱⁱⁱ	47.93 (2)
O1ⁱ—K1—O4ⁱ	46.26 (2)	O11ⁱⁱⁱ—K7—O20ⁱⁱⁱ	70.36 (3)
O2—K1—O3ⁱ	154.13 (3)	O9—K7—O20ⁱⁱⁱ	105.91 (3)
O9ⁱ—K1—O3ⁱ	87.31 (3)	O15^xiv—K7—O20ⁱⁱⁱ	154.20 (2)
O23ⁱ—K1—O3ⁱ	74.07 (4)	O24^xv—K8—O13^xiv	93.69 (3)
O5^v—K1—O3ⁱ	105.70 (4)	O24^xv—K8—O16^xv	69.23 (3)
O21ⁱ—K1—O3ⁱ	75.45 (3)	O13^xiv—K8—O16^xv	151.96 (3)
O1ⁱ—K1—O3ⁱ	47.66 (2)	O24^xv—K8—O10ⁱⁱⁱ	115.18 (3)
O4ⁱ—K1—O3ⁱ	46.44 (3)	O13^xiv—K8—O10ⁱⁱⁱ	123.38 (3)
O5^v—K2—O2	84.23 (3)	O16^xv—K8—O10ⁱⁱⁱ	84.54 (3)
O5^v—K2—O6	110.99 (3)	O24^xv—K8—O16^xiv	140.75 (3)
O2—K2—O6	143.69 (3)	O13^xiv—K8—O16^xiv	54.79 (3)
O5^v—K2—O17^xiii	125.94 (3)	O16^xv—K8—O16^xiv	127.063 (19)
O2—K2—O17^xiii	85.69 (3)	O10ⁱⁱⁱ—K8—O16^xiv	102.63 (2)
O6—K2—O17^xiii	108.13 (3)	O24^xv—K8—O12ⁱⁱⁱ	75.02 (3)
O5^v—K2—O7	144.48 (3)	O13^xiv—K8—O12ⁱⁱⁱ	98.75 (3)
O2—K2—O7	94.94 (3)	O16^xv—K8—O12ⁱⁱⁱ	97.98 (3)
O6—K2—O7	53.24 (3)	O10ⁱⁱⁱ—K8—O12ⁱⁱⁱ	50.65 (3)
O17^xiii—K2—O7	89.24 (3)	O16^xiv—K8—O12ⁱⁱⁱ	127.26 (2)
O5^v—K2—O19^xiii	91.51 (3)	O24^xv—K8—O11ⁱⁱⁱ	118.61 (3)
O2—K2—O19^xiii	123.16 (3)	O13^xiv—K8—O11ⁱⁱⁱ	73.93 (3)
O6—K2—O19^xiii	90.25 (3)	O16^xv—K8—O11ⁱⁱⁱ	133.49 (3)
O17^xiii—K2—O19^xiii	52.44 (3)	O10ⁱⁱⁱ—K8—O11ⁱⁱⁱ	49.66 (3)
O7—K2—O19^xiii	117.53 (3)	O16^xiv—K8—O11ⁱⁱⁱ	78.05 (3)
O17^xiii—K3—O22ⁱ	141.01 (3)	O12ⁱⁱⁱ—K8—O11ⁱⁱⁱ	49.56 (2)
O17^xiii—K3—O11ⁱⁱⁱ	108.28 (3)	O22ⁱ—K9—O3	88.63 (4)
O22ⁱ—K3—O11ⁱⁱⁱ	95.71 (3)	O22ⁱ—K9—O24	165.65 (3)
O17^xiii—K3—O2	86.06 (3)	O3—K9—O24	105.39 (3)
O22ⁱ—K3—O2	96.21 (3)	O22ⁱ—K9—O16	101.07 (4)
O11ⁱⁱⁱ—K3—O2	138.28 (3)	O3—K9—O16	169.42 (3)
O17^xiii—K3—O21ⁱ	88.37 (3)	O24—K9—O16	64.73 (3)
O22ⁱ—K3—O21ⁱ	54.13 (3)	O22ⁱ—K9—O15^xiv	104.22 (3)
O11ⁱⁱⁱ—K3—O21ⁱ	137.29 (3)	O3—K9—O15^xiv	75.10 (3)
O2—K3—O21ⁱ	80.11 (3)	O24—K9—O15^xiv	77.10 (3)
O17^xiii—K3—O3	124.84 (3)	O16—K9—O15^xiv	98.19 (3)
O22ⁱ—K3—O3	84.42 (4)	O22ⁱ—K9—O12ⁱ	112.94 (3)
O11ⁱⁱⁱ—K3—O3	89.56 (3)	O3—K9—O12ⁱ	87.10 (3)
O2—K3—O3	52.20 (3)	O24—K9—O12ⁱ	71.65 (3)
O21ⁱ—K3—O3	113.19 (3)	O16—K9—O12ⁱ	92.90 (3)
O19^iv—K4—O5ⁱⁱⁱ	95.09 (3)	O15^xiv—K9—O12ⁱ	138.23 (3)
O19^iv—K4—O6	85.91 (3)	O22ⁱ—K9—O23ⁱ	48.17 (2)
O5ⁱⁱⁱ—K4—O6	175.02 (3)	O3—K9—O23ⁱ	101.27 (3)
O19^iv—K4—O19^xiii	80.50 (3)	O24—K9—O23ⁱ	129.23 (3)
O5ⁱⁱⁱ—K4—O19^xiii	90.82 (4)	O16—K9—O23ⁱ	88.46 (3)
O6—K4—O19^xiii	94.15 (4)	O15^xiv—K9—O23ⁱ	152.38 (2)
O19^iv—K4—O1^vii	86.01 (3)	O12ⁱ—K9—O23ⁱ	67.43 (2)
O5ⁱⁱⁱ—K4—O1^vii	79.67 (4)

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

Experimental details

Crystal data
Chemical formula	K₉Al₃(PO₄)₆
M_r	1002.66
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	113
a, b, c (Å)	20.289 (4), 9.835 (2), 13.521 (3)
β (°)	100.56 (3)
V (Å³)	2652.2 (9)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.02
Crystal size (mm)	0.26 × 0.20 × 0.18

Data collection
Diffractometer	Bruker SMART 1000
Absorption correction	Numerical (CrystalClear; Rigaku/MSC, 2005)
T_min, T_max	0.622, 0.713
No. of measured, independent and observed [I > 2σ(I)] reflections	35263, 11751, 10169
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.834

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.023, 0.059, 1.10
No. of reflections	11751
No. of parameters	380
Δρ_max, Δρ_min (e Å⁻³)	0.54, −0.52

Computer programs: CrystalClear (Rigaku/MSC, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2006), CrystalStructure (Rigaku/MSC, 2005).

Characterization of K—O coordination spheres; coordination number as well as minimal and maximal distances (Å) within the coordination spheres for each K atom are given. top

atom K	coord. number	K—O distances (Å)
K1	8	2.6202 (10)–3.2026 (12)
K2	7	2.5994 (9)–2.9721 (10)
K3	6	2.6337 (11)–2.9790 (11)
K4	6	2.7005 (10)–3.0451 (10)
K5	8	2.6787 (9)–3.3087 (12)
K6	7	2.6690 (10)–3.0404 (9)
K7	7	2.6369 (9)–3.0973 (10)
K8	7	2.5736 (9)–3.0747 (10)
K9	7	2.6965 (9)–3.3094 (11)

Characterization of K—O coordination spheres; the minimal and maximal K—O distances (Å) for the terminal and bridging oxygens (there is only one bridging oxygen in the coordination spheres of K2, K3, and K8). top

atom K	K—O_terminal / K—O_bridge distances (Å)
K1	2.6202 (12)–3.2027 (18) / 3.0287 (14)–3.1684 (16)
K2	2.5994 (12)–2.9722 (14) / 2.8588 (14)
K3	2.6337 (13)–2.9790 (14) / 2.8348 (13)
K4	2.7006 (13)–2.7762 (15) / 2.9576 (15)–3.0451 (13)
K5	2.6787 (11)–3.3088 (19) / 3.1012 (15)–3.2476 (15)
K6	2.6690 (14)–2.9869 (16) / 2.8236 (13)–3.0405 (13)
K7	2.6368 (12)–2.9005 (15) / 2.7891 (14)–3.0974 (13)
K8	2.5737 (12)–3.0747 (13) / 2.9491 (13)
K9	2.6965 (2)–2.8865 (13) / 2.9783 (12)–3.3095 (16)

Footnotes

‡Current address: Graduate School of the Chinese Academy of Sciences, Beijing 100039, People's Republic of China.

Acknowledgements

This work was supported financially by the National Natural Science Foundation of China under grant No. 50672104.

References

Aguilo, M. & Wuensdregt, C. F. (1985). J. Cryst. Growth, 83, 549–559 CrossRef Web of Science Google Scholar
Barone, J. P. & Nancollas, G. H. (1978). J. Dent. Res. 57, 735–742. CrossRef CAS PubMed Web of Science Google Scholar
Dickinson, M. R., Gloster, L. A. W., Hopps, N. W. & King, T. A. (1996). Opt. Commun. 132, 275–278. CrossRef CAS Web of Science Google Scholar
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Masse, R. & Grenier, J. C. (1971). Bull. Soc. Fr. Mineral. Cristallogr. 94, 437–439. CAS Google Scholar
Nandini Devi, R. & Vidyasagar, K. (2000). Inorg. Chem. 39, 2391–2396. CrossRef PubMed CAS Google Scholar
Ng, H. N. & Calvo, C. (1973). Can. J. Chem. 51, 2613–2620. CrossRef CAS Web of Science Google Scholar
Noor, J. W. & Dam, B. (1986). J. Cryst. Growth, 76, 243–250. CrossRef CAS Web of Science Google Scholar
Rigaku/MSC (2005). CrystalClear and CrystalStructure. Rigaku/MSC Inc., The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar