Penta-lanthanum zinc diplumbide, La5Zn1-x Pb2+x (x ≃ 0.6).

The title non-stoichiometric penta-lanthanum zinc diplumbide, La5Zn1-x Pb2+x (x ≃ 0.6), was prepared from the elements in an evacuated silica ampoule. It adopts the Nb5Sn2Si-type structure (space group I4/mcm, Pearson symbol tI32), a ternary ordered superstructure of the W5Si3 type. Among the four independent crystallographic positions, three are fully occupied by La (Wyckoff 16k), La (4b), and Pb (8h) and one is occupied by a statistical mixture [occupancy ratio 0.394 (12):0.606 (12)] of Zn and Pb (4a). The structure is constructed by face-sharing 10-vertex polyhedra around the unmixed Pb sites. These fragments enclose channels of trans-face-sharing tetra-gonal anti-prisms occupied by the disordered Zn and Pb sites.

Related literature

For general background to electronic structure calculations, see: Andersen et al. (1986 ▶); Becke & Edgecombe (1990 ▶); Dronskowski & Blöchl (1993 ▶); Lange (1999 ▶); Nowak et al. (1991 ▶). For related structures, see: Aronsson (1955 ▶); Oshchapovsky et al. (2011a ▶,b ▶, 2012a ▶,b ▶); Stetskiv et al. (2012 ▶). For isotypic structures, see: Horyn & Lukaszewich (1970 ▶).

Experimental

Crystal data

La5Zn0.394Pb2.606

M = 1259.40

Tetragonal,

a = 12.7630 (18) Å

c = 6.3680 (13) Å

V = 1037.3 (3) Å3

Z = 4

Mo Kα radiation

μ = 63.04 mm−1

T = 153 K

0.04 × 0.02 × 0.01 mm

Data collection

Bruker P4 CCD diffractometer

Absorption correction: multi-scan (XSCANS; Bruker, 1999) T min = 0.332, T max = 0.525

3933 measured reflections

365 independent reflections

352 reflections with I > 2σ(I)

R int = 0.122

Refinement

R[F 2 > 2σ(F 2)] = 0.024

wR(F 2) = 0.058

S = 1.25

352 reflections

18 parameters

Δρmax = 2.55 e Å−3

Δρmin = −1.27 e Å−3

Data collection: XSCANS (Bruker, 1999 ▶); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2006 ▶) and VESTA (Momma & Izumi, 2008 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536813033618/hb7160sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813033618/hb7160Isup2.hkl

Additional supporting information: crystallographic information; 3D view; checkCIF report

La5Pb2.606Zn0.394	Dx = 8.068 Mg m−3
Mr = 1259.40	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4/mcm	Cell parameters from 3933 reflections
Hall symbol: -I 4 2c	θ = 4.5–27.9°
a = 12.7630 (18) Å	µ = 63.04 mm−1
c = 6.3680 (13) Å	T = 153 K
V = 1037.3 (3) Å3	Irregularly shaped, metallic grey
Z = 4	0.04 × 0.02 × 0.01 mm
F(000) = 2041.6

Bruker P4 CCD diffractometer	365 independent reflections
Radiation source: fine-focus sealed tube	352 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.122
ω scans	θmax = 27.9°, θmin = 4.5°
Absorption correction: multi-scan (XSCANS; Bruker, 1999)	h = −16→16
Tmin = 0.332, Tmax = 0.525	k = −15→16
3933 measured reflections	l = −8→8

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)] = 0.024	w = 1/[σ2(Fo2) + 23.7905P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.058	(Δ/σ)max = 0.012
S = 1.25	Δρmax = 2.55 e Å−3
352 reflections	Δρmin = −1.27 e Å−3
18 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 3948 (389)

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 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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
La1	0.08312 (9)	0.21698 (9)	0.0000	0.0229 (4)
La2	0.0000	0.5000	0.2500	0.0188 (6)
Pb3	0.16124 (5)	0.66124 (5)	0.0000	0.0187 (4)
Pb4	0.0000	0.0000	0.2500	0.0231 (9)	0.606 (12)
Zn4	0.0000	0.0000	0.2500	0.0231 (9)	0.394 (12)

	U11	U22	U33	U12	U13	U23
La1	0.0150 (6)	0.0150 (6)	0.0386 (9)	0.0005 (4)	0.000	0.000
La2	0.0171 (6)	0.0171 (6)	0.0222 (12)	0.000	0.000	0.000
Pb3	0.0137 (4)	0.0137 (4)	0.0287 (7)	−0.0013 (3)	0.000	0.000
Pb4	0.0142 (8)	0.0142 (8)	0.0410 (16)	0.000	0.000	0.000
Zn4	0.0142 (8)	0.0142 (8)	0.0410 (16)	0.000	0.000	0.000

La1—Pb3i	3.3394 (14)	La2—La1iii	4.0875 (12)
La1—Zn4ii	3.3658 (11)	Pb3—La2iii	3.3173 (9)
La1—Pb4ii	3.3658 (11)	Pb3—La1xiv	3.3394 (14)
La1—Pb4	3.3658 (11)	Pb3—La1xv	3.3394 (14)
La1—Pb3iii	3.4846 (12)	Pb3—La1iii	3.4846 (12)
La1—La1iv	3.608 (2)	Pb3—La1iv	3.4846 (12)
La1—Pb3v	3.6807 (8)	Pb3—La1xii	3.6807 (8)
La1—Pb3vi	3.6807 (8)	Pb3—La1xvi	3.6807 (8)
La1—La1vii	3.8261 (13)	Pb3—La1xi	3.6807 (8)
La1—La1viii	3.8261 (13)	Pb3—La1xvii	3.6807 (8)
La1—La1ix	3.9969 (14)	Pb4—Zn4xviii	3.1840 (7)
La2—La2x	3.1840 (7)	Pb4—Zn4ii	3.1840 (6)
La2—La2iii	3.1840 (6)	Pb4—Pb4xviii	3.1840 (7)
La2—Pb3iii	3.3173 (9)	Pb4—Pb4ii	3.1840 (6)
La2—Pb3	3.3173 (9)	Pb4—La1xix	3.3658 (11)
La2—Pb3v	3.3173 (9)	Pb4—La1ii	3.3658 (11)
La2—Pb3xi	3.3173 (9)	Pb4—La1viii	3.3658 (11)
La2—La1xii	4.0875 (12)	Pb4—La1xx	3.3658 (11)
La2—La1xi	4.0875 (12)	Pb4—La1xxi	3.3658 (11)
La2—La1xiii	4.0875 (12)	Pb4—La1xxii	3.3658 (11)
La2—La1v	4.0875 (12)	Pb4—La1xxiii	3.3658 (11)
Pb3i—La1—Zn4ii	97.62 (3)	La1xii—La2—La1	149.92 (3)
Pb3i—La1—Pb4ii	97.62 (3)	La1xi—La2—La1	98.725 (6)
Zn4ii—La1—Pb4ii	0.0	La1xiii—La2—La1	107.88 (3)
Pb3i—La1—Pb4	97.62 (3)	La1v—La2—La1	98.725 (6)
Zn4ii—La1—Pb4	56.46 (2)	La1iii—La2—La1	134.156 (16)
Pb4ii—La1—Pb4	56.46 (2)	La2iii—Pb3—La2	57.36 (2)
Pb3i—La1—Pb3iii	165.81 (4)	La2iii—Pb3—La1xiv	137.584 (15)
Zn4ii—La1—Pb3iii	94.87 (3)	La2—Pb3—La1xiv	137.584 (15)
Pb4ii—La1—Pb3iii	94.87 (3)	La2iii—Pb3—La1xv	137.584 (15)
Pb4—La1—Pb3iii	94.87 (3)	La2—Pb3—La1xv	137.584 (15)
Pb3i—La1—La1iv	57.30 (2)	La1xiv—Pb3—La1xv	65.40 (4)
Zn4ii—La1—La1iv	143.576 (15)	La2iii—Pb3—La1iii	73.83 (2)
Pb4ii—La1—La1iv	143.576 (15)	La2—Pb3—La1iii	73.83 (2)
Pb4—La1—La1iv	143.576 (15)	La1xiv—Pb3—La1iii	75.81 (4)
Pb3iii—La1—La1iv	108.51 (2)	La1xv—Pb3—La1iii	141.21 (2)
Pb3i—La1—Pb3v	79.94 (3)	La2iii—Pb3—La1iv	73.83 (2)
Zn4ii—La1—Pb3v	147.35 (3)	La2—Pb3—La1iv	73.83 (2)
Pb4ii—La1—Pb3v	147.35 (3)	La1xiv—Pb3—La1iv	141.21 (2)
Pb4—La1—Pb3v	91.356 (15)	La1xv—Pb3—La1iv	75.81 (4)
Pb3iii—La1—Pb3v	93.10 (3)	La1iii—Pb3—La1iv	142.98 (5)
La1iv—La1—Pb3v	60.650 (17)	La2iii—Pb3—La1xii	120.60 (3)
Pb3i—La1—Pb3vi	79.94 (3)	La2—Pb3—La1xii	71.26 (2)
Zn4ii—La1—Pb3vi	91.356 (15)	La1xiv—Pb3—La1xii	69.21 (3)
Pb4ii—La1—Pb3vi	91.356 (15)	La1xv—Pb3—La1xii	100.06 (3)
Pb4—La1—Pb3vi	147.35 (3)	La1iii—Pb3—La1xii	64.48 (2)
Pb3iii—La1—Pb3vi	93.10 (3)	La1iv—Pb3—La1xii	119.919 (19)
La1iv—La1—Pb3vi	60.650 (17)	La2iii—Pb3—La1xvi	71.26 (2)
Pb3v—La1—Pb3vi	119.78 (3)	La2—Pb3—La1xvi	120.60 (3)
Pb3i—La1—La1vii	122.81 (3)	La1xiv—Pb3—La1xvi	69.21 (3)
Zn4ii—La1—La1vii	55.363 (14)	La1xv—Pb3—La1xvi	100.06 (3)
Pb4ii—La1—La1vii	55.363 (14)	La1iii—Pb3—La1xvi	64.48 (2)
Pb4—La1—La1vii	102.64 (3)	La1iv—Pb3—La1xvi	119.919 (19)
Pb3iii—La1—La1vii	60.24 (3)	La1xii—Pb3—La1xvi	119.78 (3)
La1iv—La1—La1vii	113.086 (18)	La2iii—Pb3—La1xi	120.60 (3)
Pb3v—La1—La1vii	150.47 (3)	La2—Pb3—La1xi	71.26 (2)
Pb3vi—La1—La1vii	55.274 (16)	La1xiv—Pb3—La1xi	100.06 (3)
Pb3i—La1—La1viii	122.81 (3)	La1xv—Pb3—La1xi	69.21 (3)
Zn4ii—La1—La1viii	102.64 (3)	La1iii—Pb3—La1xi	119.919 (19)
Pb4ii—La1—La1viii	102.64 (3)	La1iv—Pb3—La1xi	64.48 (2)
Pb4—La1—La1viii	55.363 (14)	La1xii—Pb3—La1xi	58.70 (3)
Pb3iii—La1—La1viii	60.24 (3)	La1xvi—Pb3—La1xi	167.71 (4)
La1iv—La1—La1viii	113.086 (18)	La2iii—Pb3—La1xvii	71.26 (2)
Pb3v—La1—La1viii	55.274 (16)	La2—Pb3—La1xvii	120.60 (3)
Pb3vi—La1—La1viii	150.47 (3)	La1xiv—Pb3—La1xvii	100.06 (3)
La1vii—La1—La1viii	112.64 (6)	La1xv—Pb3—La1xvii	69.21 (3)
Pb3i—La1—La1ix	59.42 (3)	La1iii—Pb3—La1xvii	119.919 (19)
Zn4ii—La1—La1ix	53.576 (15)	La1iv—Pb3—La1xvii	64.48 (2)
Pb4ii—La1—La1ix	53.576 (15)	La1xii—Pb3—La1xvii	167.71 (4)
Pb4—La1—La1ix	99.20 (3)	La1xvi—Pb3—La1xvii	58.70 (3)
Pb3iii—La1—La1ix	124.98 (2)	La1xi—Pb3—La1xvii	119.78 (3)
La1iv—La1—La1ix	90.0	Zn4xviii—Pb4—Zn4ii	180.0
Pb3v—La1—La1ix	138.92 (3)	Zn4xviii—Pb4—Pb4xviii	0.0
Pb3vi—La1—La1ix	51.362 (18)	Zn4ii—Pb4—Pb4xviii	180.0
La1vii—La1—La1ix	64.79 (2)	Zn4xviii—Pb4—Pb4ii	180.0
La1viii—La1—La1ix	154.150 (9)	Zn4ii—Pb4—Pb4ii	0.0
La2x—La2—La2iii	180.0	Pb4xviii—Pb4—Pb4ii	180.0
La2x—La2—Pb3iii	118.679 (10)	Zn4xviii—Pb4—La1xix	61.771 (11)
La2iii—La2—Pb3iii	61.321 (10)	Zn4ii—Pb4—La1xix	118.229 (11)
La2x—La2—Pb3	118.679 (10)	Pb4xviii—Pb4—La1xix	61.771 (11)
La2iii—La2—Pb3	61.321 (10)	Pb4ii—Pb4—La1xix	118.229 (11)
Pb3iii—La2—Pb3	122.64 (2)	Zn4xviii—Pb4—La1ii	118.229 (11)
La2x—La2—Pb3v	61.321 (10)	Zn4ii—Pb4—La1ii	61.771 (11)
La2iii—La2—Pb3v	118.679 (10)	Pb4xviii—Pb4—La1ii	118.229 (11)
Pb3iii—La2—Pb3v	103.315 (9)	Pb4ii—Pb4—La1ii	61.771 (11)
Pb3—La2—Pb3v	103.315 (9)	La1xix—Pb4—La1ii	137.93 (4)
La2x—La2—Pb3xi	61.321 (10)	Zn4xviii—Pb4—La1viii	61.771 (11)
La2iii—La2—Pb3xi	118.679 (10)	Zn4ii—Pb4—La1viii	118.229 (11)
Pb3iii—La2—Pb3xi	103.315 (9)	Pb4xviii—Pb4—La1viii	61.771 (11)
Pb3—La2—Pb3xi	103.315 (9)	Pb4ii—Pb4—La1viii	118.229 (11)
Pb3v—La2—Pb3xi	122.64 (2)	La1xix—Pb4—La1viii	77.072 (9)
La2x—La2—La1xii	67.078 (8)	La1ii—Pb4—La1viii	143.26 (4)
La2iii—La2—La1xii	112.922 (8)	Zn4xviii—Pb4—La1	118.229 (11)
Pb3iii—La2—La1xii	153.655 (15)	Zn4ii—Pb4—La1	61.771 (11)
Pb3—La2—La1xii	58.513 (15)	Pb4xviii—Pb4—La1	118.229 (11)
Pb3v—La2—La1xii	101.555 (15)	Pb4ii—Pb4—La1	61.771 (11)
Pb3xi—La2—La1xii	54.961 (15)	La1xix—Pb4—La1	72.85 (3)
La2x—La2—La1xi	67.078 (8)	La1ii—Pb4—La1	123.54 (2)
La2iii—La2—La1xi	112.922 (8)	La1viii—Pb4—La1	69.27 (3)
Pb3iii—La2—La1xi	153.655 (15)	Zn4xviii—Pb4—La1xx	118.229 (11)
Pb3—La2—La1xi	58.513 (15)	Zn4ii—Pb4—La1xx	61.771 (11)
Pb3v—La2—La1xi	54.961 (15)	Pb4xviii—Pb4—La1xx	118.229 (11)
Pb3xi—La2—La1xi	101.555 (15)	Pb4ii—Pb4—La1xx	61.771 (11)
La1xii—La2—La1xi	52.38 (3)	La1xix—Pb4—La1xx	69.27 (3)
La2x—La2—La1xiii	112.922 (8)	La1ii—Pb4—La1xx	77.072 (9)
La2iii—La2—La1xiii	67.078 (8)	La1viii—Pb4—La1xx	137.93 (4)
Pb3iii—La2—La1xiii	54.961 (15)	La1—Pb4—La1xx	77.072 (9)
Pb3—La2—La1xiii	101.555 (15)	Zn4xviii—Pb4—La1xxi	118.229 (11)
Pb3v—La2—La1xiii	153.655 (15)	Zn4ii—Pb4—La1xxi	61.771 (11)
Pb3xi—La2—La1xiii	58.513 (15)	Pb4xviii—Pb4—La1xxi	118.229 (11)
La1xii—La2—La1xiii	98.725 (6)	Pb4ii—Pb4—La1xxi	61.771 (11)
La1xi—La2—La1xiii	149.92 (3)	La1xix—Pb4—La1xxi	143.26 (4)
La2x—La2—La1v	67.078 (8)	La1ii—Pb4—La1xxi	77.072 (9)
La2iii—La2—La1v	112.922 (8)	La1viii—Pb4—La1xxi	72.85 (3)
Pb3iii—La2—La1v	58.513 (15)	La1—Pb4—La1xxi	77.072 (10)
Pb3—La2—La1v	153.655 (15)	La1xx—Pb4—La1xxi	123.54 (2)
Pb3v—La2—La1v	101.555 (15)	Zn4xviii—Pb4—La1xxii	61.771 (11)
Pb3xi—La2—La1v	54.961 (15)	Zn4ii—Pb4—La1xxii	118.229 (11)
La1xii—La2—La1v	107.88 (3)	Pb4xviii—Pb4—La1xxii	61.771 (11)
La1xi—La2—La1v	134.156 (16)	Pb4ii—Pb4—La1xxii	118.229 (11)
La1xiii—La2—La1v	55.81 (2)	La1xix—Pb4—La1xxii	123.54 (2)
La2x—La2—La1iii	112.922 (8)	La1ii—Pb4—La1xxii	72.85 (3)
La2iii—La2—La1iii	67.078 (8)	La1viii—Pb4—La1xxii	77.072 (9)
Pb3iii—La2—La1iii	101.555 (15)	La1—Pb4—La1xxii	137.93 (4)
Pb3—La2—La1iii	54.961 (15)	La1xx—Pb4—La1xxii	143.26 (4)
Pb3v—La2—La1iii	153.655 (15)	La1xxi—Pb4—La1xxii	69.27 (3)
Pb3xi—La2—La1iii	58.513 (15)	Zn4xviii—Pb4—La1xxiii	61.771 (11)
La1xii—La2—La1iii	55.81 (2)	Zn4ii—Pb4—La1xxiii	118.229 (11)
La1xi—La2—La1iii	98.725 (6)	Pb4xviii—Pb4—La1xxiii	61.771 (11)
La1xiii—La2—La1iii	52.38 (3)	Pb4ii—Pb4—La1xxiii	118.229 (11)
La1v—La2—La1iii	98.725 (6)	La1xix—Pb4—La1xxiii	77.072 (9)
La2x—La2—La1	112.922 (8)	La1ii—Pb4—La1xxiii	69.27 (3)
La2iii—La2—La1	67.078 (8)	La1viii—Pb4—La1xxiii	123.54 (2)
Pb3iii—La2—La1	54.961 (15)	La1—Pb4—La1xxiii	143.26 (4)
Pb3—La2—La1	101.555 (15)	La1xx—Pb4—La1xxiii	72.85 (3)
Pb3v—La2—La1	58.513 (15)	La1xxi—Pb4—La1xxiii	137.93 (4)
Pb3xi—La2—La1	153.655 (15)	La1xxii—Pb4—La1xxiii	77.072 (9)

Bond	Length (Å)	-iCOHPa (eV)	Contractionb (%) (r1+r2) - δ - 100%r1+r2
La1I—La1VII	3.611	0.59	3.4
La1I—La1V	3.825	0.45	-2.3
La1I—La1VIII	3.997	0.40	-6.9
La1I—La2IX	4.088	0.40	-9.3
La1I—La2IX	4.088	0.40	-9.3
La1I—La1III	4.193	0.32	-12.1
La1I—La1IV	4.193	0.32	-12.1
La2IX—La2X	3.184	1.26	14.9
La2IX—La1II	4.088	0.40	-9.3
La2IX—La1III	4.088	0.40	-9.3
La2IX—La1IV	4.088	0.40	-9.3
La2IX—La1V	4.088	0.40	-9.3
La2IX—La1VI	4.088	0.40	-9.3
La2IX—La1VII	4.088	0.40	-9.3
La2IX—La1VIII	4.088	0.40	-9.3
La1I—Zn4XV	3.365	0.26	-5.2
La1I—Zn4XVI	3.365	0.26	-5.2
La1II—Zn4XV	3.365	0.26	-5.2
La1III—Zn4XV	3.365	0.26	-5.2
La1IV—Zn4XV	3.365	0.26	-5.2
La1V—Zn4XV	3.365	0.26	-5.2
La1VI—Zn4XV	3.365	0.26	-5.2
La1VII—Zn4XV	3.365	0.26	-5.2
La1VIII—Zn4XV	3.365	0.26	-5.2
La2IX—Pb3XI	3.319	1.10	7.0
La2IX—Pb3XII	3.319	1.10	7.0
La2IX—Pb3XIII	3.319	1.10	7.0
La2IX—Pb3XIV	3.319	1.10	7.0
La2X—Pb3XI	3.319	1.10	7.0
La1III—Pb3XI	3.339	1.09	6.5
La1VI—Pb3XI	3.339	1.09	6.5
La1VIII—Pb3XI	3.484	0.93	2.4
La1IV—Pb3XI	3.681	0.72	-3.1
La1V—Pb3XI	3.681	0.72	-3.1
Zn4XV—Zn4XVI	3.184	-0.49	-19.7

Table 1

Bond lengths, negative iCOHP values and distance contractions in the La5Zn1−Pb2+ compound

Bond	Length (δ in Å)	-iCOHPa (eV)	Contractionb (%) 100%
La1—La1	3.611	0.59	3.4
La1—La1	3.825	0.45	−2.3
La1—La1	3.997	0.40	−6.9
La1—La2	4.088	0.40	−9.3
La1—La1	4.193	0.32	−12.1
La2I—La2	3.184	1.26	14.9
La1—Zn4	3.365	0.26	−5.2
La2—Pb3	3.319	1.10	7.0
La1—Pb3	3.339	1.09	6.5
La1—Pb3	3.484	0.93	2.4
La1—Pb3	3.681	0.72	−3.1
Zn4—Zn4	3.184	−0.49	−19.7

Notes: (a) integrated Crystal Orbital Hamiltonian Population (see Dronskowski & Blöchl, 1993 ▶); calculated negative iCOHP values enable qualitative estimation of energies of two-center bonds; (b) based on metallic radii of elements R(La) = 1.86 Å R(Zn) = 1.33 Å and R(Pb) = 1.70 Å.