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The two title trialkaline trioxoantimonates(III), tripotassium trioxoantimonate(III), K_{3}[SbO_{3}], (I), and tricaesium trioxoantimonate(III), Cs_{3}[SbO_{3}], (II), crystallize in the cubic Na_{3}[AsS_{3}] structure type in space group P2_{1}3. The structures show discrete Ψtetrahedral [SbO_{3}]^{3−} anions with C_{3v} pointgroup symmetry. The Sb—O distances are 1.923 (4) Å in (I) and 1.928 (2) Å in (II), and the O—Sb—O bond angles are 99.5 (2)° in (I) and 100.4 (1)° in (II).
Supporting information
Crystals of (I) were grown from a mixture containing KO_{2} (Fluka AG, 99.0%), K
(AlkaliMetallhandel GmbH Bonn, 98.0%) and Sb powder (SigmaAldrich, 99.8%) in
a molar ratio of 0.5:1.5:2. The mixture was heated up to 973 K and then cooled
down to 573 K at a rate of 5 K h^{1}. Then the furnace was turned off. For
(II), CsO_{2} (803 mg, 4.87 mmol) was reacted with powdered Sb (198 mg, 1.62 mmol) in a corundum crucible under an argon atmosphere. The mixture was heated
up to 973 K within 3.5 h and then cooled down to room temperature at a rate of
5 K h^{1}. The Xray powder pattern of the sample (Stadi P diffractometer with
linear PSD; Stoe & Cie, Darmstadt) could be indexed with the singlecrystal
data of (II) and showed weak reflections of Cs_{3}[SbO_{4}] and elemental Sb.
Both title compounds formed hydroscopic colourless crystals, which were
handled in a dry box under argon and prepared in capillaries filled with dried
oil.
For both compounds, data collection: CAD4 Software (EnrafNonius, 1989) Query; cell refinement: CAD4 Software Query; data reduction: HELENA (Spek, 1996); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1968) and DRAWxtl (Finger & Kroeker, 1999); software used to prepare material for publication: SHELXL97.
(I) Tripotassium trioxoantimonate(III)
top
Crystal data top
K_{3}[SbO_{3}]  D_{x} = 3.272 Mg m^{−}^{3} 
M_{r} = 287.05  Mo Kα radiation, λ = 0.71070 Å 
Cubic, P2_{1}3  Cell parameters from 25 reflections 
Hall symbol: P 2ac 2ab 3  θ = 3.8–29.3° 
a = 8.352 (5) Å  µ = 6.77 mm^{−}^{1} 
V = 582.7 (5) Å^{3}  T = 293 K 
Z = 4  Prism, colourless 
F(000) = 528  0.1 × 0.1 × 0.1 mm 
Data collection top
EnrafNonius CAD4 diffractometer  377 reflections with I > 2σ(I) 
Radiation source: finefocus sealed tube  R_{int} = 0.090 
Graphite monochromator  θ_{max} = 27.4°, θ_{min} = 4.2° 
ω/2θ scans  h = 0→10 
Absorption correction: ψ scan (North et al., 1968)  k = −10→10 
T_{min} = 0.497, T_{max} = 0.508  l = −10→0 
1510 measured reflections  3 standard reflections every 120 min 
455 independent reflections  intensity decay: none 
Refinement top
Refinement on F^{2}  Secondary atom site location: difference Fourier map 
Leastsquares matrix: full  w = 1/[σ^{2}(F_{o}^{2}) + (0.0219P)^{2}] where P = (F_{o}^{2} + 2F_{c}^{2})/3 
R[F^{2} > 2σ(F^{2})] = 0.026  (Δ/σ)_{max} < 0.001 
wR(F^{2}) = 0.054  Δρ_{max} = 0.72 e Å^{−}^{3} 
S = 1.04  Δρ_{min} = −1.03 e Å^{−}^{3} 
455 reflections  Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^{*}=kFc[1+0.001xFc^{2}λ^{3}/sin(2θ)]^{1/4} 
20 parameters  Extinction coefficient: 0.0025 (9) 
0 restraints  Absolute structure: Flack (1983), 189 Friedel pairs 
Primary atom site location: structureinvariant direct methods  Absolute structure parameter: −0.03 (11) 
Crystal data top
K_{3}[SbO_{3}]  Z = 4 
M_{r} = 287.05  Mo Kα radiation 
Cubic, P2_{1}3  µ = 6.77 mm^{−}^{1} 
a = 8.352 (5) Å  T = 293 K 
V = 582.7 (5) Å^{3}  0.1 × 0.1 × 0.1 mm 
Data collection top
EnrafNonius CAD4 diffractometer  377 reflections with I > 2σ(I) 
Absorption correction: ψ scan (North et al., 1968)  R_{int} = 0.090 
T_{min} = 0.497, T_{max} = 0.508  3 standard reflections every 120 min 
1510 measured reflections  intensity decay: none 
455 independent reflections  
Refinement top
R[F^{2} > 2σ(F^{2})] = 0.026  0 restraints 
wR(F^{2}) = 0.054  Δρ_{max} = 0.72 e Å^{−}^{3} 
S = 1.04  Δρ_{min} = −1.03 e Å^{−}^{3} 
455 reflections  Absolute structure: Flack (1983), 189 Friedel pairs 
20 parameters  Absolute structure parameter: −0.03 (11) 
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. 
Refinement. Refinement of F^{2} against ALL reflections. The weighted Rfactor
wR and goodness of fit S are based on F^{2}, conventional
Rfactors R are based on F, with F set to zero for
negative F^{2}. The threshold expression of F^{2} >
σ(F^{2}) is used only for calculating Rfactors(gt) etc.
and is not relevant to the choice of reflections for refinement.
Rfactors based on F^{2} 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 (Å^{2}) top  x  y  z  U_{iso}*/U_{eq}  
Sb  0.51456 (4)  0.51456 (4)  0.51456 (4)  0.01377 (18)  
K1  0.7890 (2)  0.7890 (2)  0.7890 (2)  0.0192 (5)  
K2  0.2839 (2)  0.2839 (2)  0.2839 (2)  0.0177 (5)  
K3  0.02565 (16)  0.02565 (16)  0.02565 (16)  0.0242 (4)  
O1  0.0051 (5)  0.2108 (4)  0.4391 (4)  0.0206 (8)  
Atomic displacement parameters (Å^{2}) top  U^{11}  U^{22}  U^{33}  U^{12}  U^{13}  U^{23} 
Sb  0.01377 (18)  0.01377 (18)  0.01377 (18)  −0.00078 (16)  −0.00078 (16)  −0.00078 (16) 
K1  0.0192 (5)  0.0192 (5)  0.0192 (5)  0.0025 (8)  0.0025 (8)  0.0025 (8) 
K2  0.0177 (5)  0.0177 (5)  0.0177 (5)  −0.0006 (7)  −0.0006 (7)  −0.0006 (7) 
K3  0.0242 (4)  0.0242 (4)  0.0242 (4)  −0.0008 (5)  −0.0008 (5)  −0.0008 (5) 
O1  0.0165 (19)  0.0179 (17)  0.0274 (17)  −0.003 (2)  −0.0001 (19)  0.0076 (13) 
Geometric parameters (Å, º) top
Sb—O1^{i}  1.923 (4)  K2—O1^{i}  2.961 (5) 
Sb—O1^{ii}  1.923 (4)  K2—O1^{iii}  2.961 (5) 
Sb—O1^{iii}  1.923 (4)  K2—O1^{ii}  2.961 (5) 
K1—O1^{iv}  2.758 (5)  K3—O1^{xii}  2.659 (4) 
K1—O1^{v}  2.758 (5)  K3—O1^{xiii}  2.659 (4) 
K1—O1^{vi}  2.758 (5)  K3—O1^{xiv}  2.659 (4) 
K1—O1^{vii}  2.922 (5)  O1—Sb^{xv}  1.923 (4) 
K1—O1^{viii}  2.922 (5)  O1—K3^{xvi}  2.659 (4) 
K1—O1^{ix}  2.922 (5)  O1—K1^{xvii}  2.758 (5) 
K2—O1^{x}  2.734 (4)  O1—K1^{xviii}  2.922 (5) 
K2—O1^{xi}  2.734 (4)  O1—K2^{xv}  2.961 (5) 
K2—O1  2.734 (4)   
   
O1^{i}—Sb—O1^{ii}  99.50 (15)  O1^{ii}—Sb—O1^{iii}  99.51 (15) 
O1^{i}—Sb—O1^{iii}  99.50 (15)   
Symmetry codes: (i) x+1/2, −y+1/2, −z+1; (ii) −z+1, x+1/2, −y+1/2; (iii) −y+1/2, −z+1, x+1/2; (iv) z+1/2, −x+1/2, −y+1; (v) −y+1, z+1/2, −x+1/2; (vi) −x+1/2, −y+1, z+1/2; (vii) −x+1, y+1/2, −z+3/2; (viii) y+1/2, −z+3/2, −x+1; (ix) −z+3/2, −x+1, y+1/2; (x) z, x, y; (xi) y, z, x; (xii) −x, y−1/2, −z+1/2; (xiii) −z+1/2, −x, y−1/2; (xiv) y−1/2, −z+1/2, −x; (xv) x−1/2, −y+1/2, −z+1; (xvi) −x, y+1/2, −z+1/2; (xvii) −x+1/2, −y+1, z−1/2; (xviii) −x+1, y−1/2, −z+3/2. 
(II) Tricaesium trioxoantimonate(III)
top
Crystal data top
Cs_{3}[SbO_{3}]  D_{x} = 4.950 Mg m^{−}^{3} 
M_{r} = 568.48  Mo Kα radiation, λ = 0.71070 Å 
Cubic, P2_{1}3  Cell parameters from 25 reflections 
Hall symbol: P 2ac 2ab 3  θ = 2.3–32.8° 
a = 9.1369 (10) Å  µ = 17.65 mm^{−}^{1} 
V = 762.78 (14) Å^{3}  T = 293 K 
Z = 4  Prism, colourless 
F(000) = 960  0.11 × 0.08 × 0.06 mm 
Data collection top
EnrafNonius CAD4 diffractometer  540 reflections with I > 2σ(I) 
Radiation source: finefocus sealed tube  R_{int} = 0.063 
Graphite monochromator  θ_{max} = 27.4°, θ_{min} = 4.5° 
ω/2θ scans  h = −11→11 
Absorption correction: ψ scan (North et al., 1968)  k = −11→11 
T_{min} = 0.197, T_{max} = 0.347  l = 0→11 
3665 measured reflections  3 standard reflections every 120 min 
586 independent reflections  intensity decay: none 
Refinement top
Refinement on F^{2}  Secondary atom site location: difference Fourier map 
Leastsquares matrix: full  w = 1/[σ^{2}(F_{o}^{2}) + 0.2365P] where P = (F_{o}^{2} + 2F_{c}^{2})/3 
R[F^{2} > 2σ(F^{2})] = 0.014  (Δ/σ)_{max} = 0.001 
wR(F^{2}) = 0.036  Δρ_{max} = 0.68 e Å^{−}^{3} 
S = 1.07  Δρ_{min} = −0.59 e Å^{−}^{3} 
750 reflections  Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^{*}=kFc[1+0.001xFc^{2}λ^{3}/sin(2θ)]^{1/4} 
23 parameters  Extinction coefficient: 0.00079 (8) 
0 restraints  Absolute structure: Flack (1983), 240 Friedel pairs 
Primary atom site location: structureinvariant direct methods  Absolute structure parameter: 0.06 (6) 
Crystal data top
Cs_{3}[SbO_{3}]  Z = 4 
M_{r} = 568.48  Mo Kα radiation 
Cubic, P2_{1}3  µ = 17.65 mm^{−}^{1} 
a = 9.1369 (10) Å  T = 293 K 
V = 762.78 (14) Å^{3}  0.11 × 0.08 × 0.06 mm 
Data collection top
EnrafNonius CAD4 diffractometer  540 reflections with I > 2σ(I) 
Absorption correction: ψ scan (North et al., 1968)  R_{int} = 0.063 
T_{min} = 0.197, T_{max} = 0.347  3 standard reflections every 120 min 
3665 measured reflections  intensity decay: none 
586 independent reflections  
Refinement top
R[F^{2} > 2σ(F^{2})] = 0.014  0 restraints 
wR(F^{2}) = 0.036  Δρ_{max} = 0.68 e Å^{−}^{3} 
S = 1.07  Δρ_{min} = −0.59 e Å^{−}^{3} 
750 reflections  Absolute structure: Flack (1983), 240 Friedel pairs 
23 parameters  Absolute structure parameter: 0.06 (6) 
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. 
Refinement. Refinement of F^{2} against ALL reflections. The weighted Rfactor
wR and goodness of fit S are based on F^{2}, conventional
Rfactors R are based on F, with F set to zero for
negative F^{2}. The threshold expression of F^{2} >
σ(F^{2}) is used only for calculating Rfactors(gt) etc.
and is not relevant to the choice of reflections for refinement.
Rfactors based on F^{2} 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 (Å^{2}) top  x  y  z  U_{iso}*/U_{eq}  
Cs1  0.77732 (3)  0.77732 (3)  0.77732 (3)  0.02308 (10)  
Cs2  0.27318 (3)  0.27318 (3)  0.27318 (3)  0.02379 (11)  
Cs3  0.01855 (3)  0.01855 (3)  0.01855 (3)  0.02933 (10)  
Sb1  0.50362 (2)  0.50362 (2)  0.50362 (2)  0.01958 (8)  
O1  0.0055 (3)  0.2041 (3)  0.4592 (3)  0.0295 (5)  
Atomic displacement parameters (Å^{2}) top  U^{11}  U^{22}  U^{33}  U^{12}  U^{13}  U^{23} 
Cs1  0.02308 (10)  0.02308 (10)  0.02308 (10)  0.00097 (10)  0.00097 (10)  0.00097 (10) 
Cs2  0.02379 (11)  0.02379 (11)  0.02379 (11)  −0.00051 (9)  −0.00051 (9)  −0.00051 (9) 
Cs3  0.02933 (10)  0.02933 (10)  0.02933 (10)  −0.00225 (10)  −0.00225 (10)  −0.00225 (10) 
Sb1  0.01958 (8)  0.01958 (8)  0.01958 (8)  −0.00125 (9)  −0.00125 (9)  −0.00125 (9) 
O1  0.0282 (13)  0.0266 (11)  0.0336 (12)  −0.0037 (10)  −0.0021 (12)  0.0089 (11) 
Geometric parameters (Å, º) top
Cs1—O1^{i}  3.077 (2)  Cs3—O1^{xii}  2.888 (2) 
Cs1—O1^{ii}  3.077 (2)  Cs3—O1^{xiii}  2.888 (2) 
Cs1—O1^{iii}  3.077 (2)  Cs3—O1^{xiv}  2.888 (2) 
Cs1—O1^{iv}  3.191 (3)  Sb1—O1^{ix}  1.928 (2) 
Cs1—O1^{v}  3.191 (2)  Sb1—O1^{x}  1.928 (2) 
Cs1—O1^{vi}  3.191 (2)  Sb1—O1^{xi}  1.928 (2) 
Cs2—O1^{vii}  3.044 (3)  O1—Sb1^{xv}  1.928 (2) 
Cs2—O1^{viii}  3.044 (3)  O1—Cs3^{xvi}  2.888 (2) 
Cs2—O1  3.044 (3)  O1—Cs1^{xvii}  3.077 (2) 
Cs2—O1^{ix}  3.245 (3)  O1—Cs1^{xviii}  3.191 (2) 
Cs2—O1^{x}  3.245 (3)  O1—Cs2^{xv}  3.245 (3) 
Cs2—O1^{xi}  3.245 (3)   
   
O1^{ix}—Sb1—O1^{x}  100.43 (9)   
Symmetry codes: (i) z+1/2, −x+1/2, −y+1; (ii) −y+1, z+1/2, −x+1/2; (iii) −x+1/2, −y+1, z+1/2; (iv) −z+3/2, −x+1, y+1/2; (v) −x+1, y+1/2, −z+3/2; (vi) y+1/2, −z+3/2, −x+1; (vii) z, x, y; (viii) y, z, x; (ix) −z+1, x+1/2, −y+1/2; (x) x+1/2, −y+1/2, −z+1; (xi) −y+1/2, −z+1, x+1/2; (xii) −z+1/2, −x, y−1/2; (xiii) −x, y−1/2, −z+1/2; (xiv) y−1/2, −z+1/2, −x; (xv) x−1/2, −y+1/2, −z+1; (xvi) −x, y+1/2, −z+1/2; (xvii) −x+1/2, −y+1, z−1/2; (xviii) −x+1, y−1/2, −z+3/2. 
Experimental details
 (I)  (II) 
Crystal data 
Chemical formula  K_{3}[SbO_{3}]  Cs_{3}[SbO_{3}] 
M_{r}  287.05  568.48 
Crystal system, space group  Cubic, P2_{1}3  Cubic, P2_{1}3 
Temperature (K)  293  293 
a (Å)  8.352 (5)  9.1369 (10) 
V (Å^{3})  582.7 (5)  762.78 (14) 
Z  4  4 
Radiation type  Mo Kα  Mo Kα 
µ (mm^{−}^{1})  6.77  17.65 
Crystal size (mm)  0.1 × 0.1 × 0.1  0.11 × 0.08 × 0.06 

Data collection 
Diffractometer  EnrafNonius CAD4 diffractometer  EnrafNonius CAD4 diffractometer 
Absorption correction  ψ scan (North et al., 1968)  ψ scan (North et al., 1968) 
T_{min}, T_{max}  0.497, 0.508  0.197, 0.347 
No. of measured, independent and observed [I > 2σ(I)] reflections  1510, 455, 377  3665, 586, 540 
R_{int}  0.090  0.063 
(sin θ/λ)_{max} (Å^{−}^{1})  0.648  0.648 

Refinement 
R[F^{2} > 2σ(F^{2})], wR(F^{2}), S  0.026, 0.054, 1.04  0.014, 0.036, 1.07 
No. of reflections  455  750 
No. of parameters  20  23 
Δρ_{max}, Δρ_{min} (e Å^{−}^{3})  0.72, −1.03  0.68, −0.59 
Absolute structure  Flack (1983), 189 Friedel pairs  Flack (1983), 240 Friedel pairs 
Absolute structure parameter  −0.03 (11)  0.06 (6) 
Selected geometric parameters (Å, º) for (I) topSb—O1^{i}  1.923 (4)  K2—O1^{iv}  2.734 (4) 
K1—O1^{ii}  2.758 (5)  K2—O1^{i}  2.961 (5) 
K1—O1^{iii}  2.922 (5)  K3—O1^{v}  2.659 (4) 
   
O1^{i}—Sb—O1^{vi}  99.50 (15)   
Symmetry codes: (i) x+1/2, −y+1/2, −z+1; (ii) z+1/2, −x+1/2, −y+1; (iii) −x+1, y+1/2, −z+3/2; (iv) z, x, y; (v) −x, y−1/2, −z+1/2; (vi) −z+1, x+1/2, −y+1/2. 
Selected geometric parameters (Å, º) for (II) topCs1—O1^{i}  3.077 (2)  Cs2—O1^{iii}  3.245 (3) 
Cs1—O1^{ii}  3.191 (3)  Cs3—O1^{iv}  2.888 (2) 
Cs2—O1  3.044 (3)  Sb1—O1^{iii}  1.928 (2) 
   
O1^{iii}—Sb1—O1^{v}  100.43 (9)   
Symmetry codes: (i) −x+1/2, −y+1, z+1/2; (ii) −z+3/2, −x+1, y+1/2; (iii) −z+1, x+1/2, −y+1/2; (iv) y−1/2, −z+1/2, −x; (v) x+1/2, −y+1/2, −z+1. 
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The oxoantimonates(III), ASbO_{2} [A = K, Rb (Hirschle & Röhr, 2000) or Cs (Hirschle & Röhr, 1998)], are isotypic with the corresponding bismuthates [A = K, Rb or Cs (Zoche & Jansen, 1998)] and contain, in accordance with the lone pair on Sb^{III}/Bi^{III}, the group V atoms coordinated by four O atoms in a Ψtrigonal bipyramidal geometry. In the compounds A_{4}[Sb_{2}O_{5}] [A = K, Rb or Cs (Hirschle & Röhr, 2000)], two [SbO_{3}] Ψ tetrahedra are connected via an oxygen ligand to form [O_{2}Sb—OSbO_{2}]^{4} `butterfly' anions. In contrast, K_{4}[Bi_{2}O_{5}] (Zoche et al., 1998) contains [Bi_{4}O_{10}]^{8} anions, with Bi both in Ψtrigonal bipyramidal and Ψtetrahedral coordination by oxygen. The bismuthates A_{3}[BiO_{3}], with Ψtetrahedral anions as characteristic building blocks, are known for the whole series of alkaline metals A. The isotypic sodium (Stöver & Hoppe, 1980) and potassium (Zoche & Jansen, 1997b) compounds can be described as defect NaCl variants, [A_{3}Bi][O_{3}], i.e. the cations A and Bi form a facecentred cubic sublattice (Cu_{3}Al type). In the rubidium (Zoche & Jansen, 1997b) and caesium (Zoche & Jansen, 1997a) phases, the cations are arranged in a bodycentered cubic sublattice (Fe_{3}Al type). For the corresponding oxoantimonate series A_{3}[SbO_{3}], only the sodium compound has been described in the literature to date (Stöver & Hoppe, 1980): Na_{3}[SbO_{3}] is isotypic with the Na and K bismuthates mentioned above. We present here the structures of two further oxoantimonates, K_{3}[SbO_{3}], (I), and Cs_{3}[SbO_{3}], (II). \sch
The isotypic compounds (I) and (II) crystallize in the cubic spacegroup P2_{1}3 with the Na_{3}[AsS_{3}] structure type (Palazzi, 1976), and are thus isotypic with the Rb and Cs oxobismuthates and most alkaline metal thio and selenoarsenates, antimonates and bismuthates. Rb_{3}[SbO_{3}] forms the same structure type, with a lattice constant (refined from Xray powder data) of 8.9523 (6) Å.
The crystal structures of (I) and (II) contain [SbO_{3}]^{3} anions with crystallographic C_{3v} point group symmetry and nearly equal Sb—O distances for the two compounds; the O—Sb—O bond angles are also very similar. The bond lengths are thus slightly longer than those observed in the sodium phase (Sb—O 1.890 Å).
The oxygen ligands are octahedrally coordinated by one Sb atom and five A cations (Fig. 1). The oxoantimonate ions form a facecentred cubic arrangement (Fig. 2), in which the alkaline metal cations occupy all tetrahedral and octahedral interstices. In an alternative description of the structure according to the concept of O'Keeffe & Hyde (1985), the A and Sb atoms form a 3:1 superstructure of a bodycentred cubic lattice, the Fe_{3}Al structure type. Whereas the corresponding K_{3}Sb phase (Emmerling & Röhr, 2001) crystallizes with a superstructure of the hexagonal Cu_{3}P type, the direct analogy of the metal atom arrangement in the intermetallic phase and the oxide is observed for Cs_{3}Sb (Emmerling & Röhr, 2001) and (II). The unit cell volumes are also comparable [762.8 (1) Å^{3} in (II) and 763.7 (1) Å^{3} in Cs_{3}Sb].