Ti insertion in the MTe(5) (M = Zr, Hf) structure type: Hf(0.78)Ti(0.22)Te(5).

The group 5 mixed-metal telluride, Hf(0.78)Ti(0.22)Te(5) (hafnium titanium penta-telluride), is isostructural with the binary phases HfTe(5) and ZrTe(5) and forms a layered structure extending parallel to (010). The layers are made up from chains of bicapped metal-centered trigonal prisms and zigzag Te chains. The metal site (site symmetry m2m) is occupied by statistically disordered Hf [78.1 (5)%] and Ti [21.9 (5)%]. In addition to the regular Te-Te pair [2.7448 (13) Å] forming the short base of the equilateral triangle of the trigonal prism, an inter-mediate Te⋯Te separation [2.9129 (9) Å] is also found. The classical charge balance of the compound can be described as [M(4+)][Te(2-)][Te(2) (2-)][Te(2) (0)] (M = Hf, Ti). The individual metal content can vary in different crystals, apparently forming a random substitutional solid solution (Hf(1-x)Ti(x))Te(5), with 0.15 ≤ x ≤ 0.22.

Related literature

For the synthesis and structure of HfTe5 and ZrTe5, see: Brattås & Kjekshus (1971 ▶); Furuseth et al. (1973 ▶, 1975 ▶). For properties of HfTe5 and ZrTe5, see: DiSalvo et al. (1981 ▶). For extensive Te⋯Te inter­actions in metal tellurides, see: Pell & Ibers (1996 ▶); Mar & Ibers (1993 ▶).

Experimental

Crystal data

Hf0.78Ti0.22Te5

M = 787.76

Orthorhombic,

a = 3.9595 (3) Å

b = 14.4350 (13) Å

c = 13.7062 (9) Å

V = 783.39 (10) Å3

Z = 4

Mo Kα radiation

μ = 28.76 mm−1

T = 290 K

0.30 × 0.04 × 0.02 mm

Data collection

Rigaku R-AXIS RAPID diffractometer

Absorption correction: multi-scan (NUMABS; Higashi, 2000 ▶) T min = 0.263, T max = 1.000

3405 measured reflections

533 independent reflections

516 reflections with I > 2σ(I)

R int = 0.059

Refinement

R[F 2 > 2σ(F 2)] = 0.029

wR(F 2) = 0.068

S = 1.16

533 reflections

23 parameters

Δρmax = 2.38 e Å−3

Δρmin = −2.07 e Å−3

Data collection: RAPID-AUTO (Rigaku, 2006 ▶); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND3 (Brandenburg, 1999 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812006691/wm2588sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812006691/wm2588Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Hf0.78Ti0.22Te5	F(000) = 1284
Mr = 787.76	Dx = 6.679 Mg m−3
Orthorhombic, Cmcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2c 2	Cell parameters from 3264 reflections
a = 3.9595 (3) Å	θ = 3.2–27.5°
b = 14.4350 (13) Å	µ = 28.76 mm−1
c = 13.7062 (9) Å	T = 290 K
V = 783.39 (10) Å3	Needle, black
Z = 4	0.30 × 0.04 × 0.02 mm

Rigaku R-AXIS RAPID diffractometer	533 independent reflections
Radiation source: fine-focus sealed tube	516 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.059
ω scans	θmax = 27.5°, θmin = 2.8°
Absorption correction: multi-scan (NUMABS; Higashi, 2000)	h = −4→5
Tmin = 0.263, Tmax = 1.000	k = −18→18
3405 measured reflections	l = −17→17

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)] = 0.029	w = 1/[σ2(Fo2) + (0.0304P)2 + 7.5394P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.068	(Δ/σ)max < 0.001
S = 1.16	Δρmax = 2.38 e Å−3
533 reflections	Δρmin = −2.07 e Å−3
23 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008)
0 restraints	Extinction coefficient: 0.00109 (14)

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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)
Hf	1	0.31435 (5)	0.25	0.0109 (3)	0.781 (5)
Ti	1	0.31435 (5)	0.25	0.0109 (3)	0.219 (5)
Te1	1	0.33665 (6)	−0.25	0.0128 (3)
Te2	1	−0.07070 (5)	0.14987 (5)	0.0169 (3)
Te3	1	0.20952 (5)	0.06526 (4)	0.0154 (2)

	U11	U22	U33	U12	U13	U23
Hf	0.0103 (4)	0.0122 (4)	0.0102 (4)	0	0	0
Ti	0.0103 (4)	0.0122 (4)	0.0102 (4)	0	0	0
Te1	0.0129 (4)	0.0121 (5)	0.0134 (4)	0	0	0
Te2	0.0164 (4)	0.0164 (4)	0.0178 (4)	0	0	0.0051 (2)
Te3	0.0155 (4)	0.0190 (4)	0.0116 (3)	0	0	−0.0010 (2)

M—Te2i	2.9251 (6)	Te1—Mv	2.9446 (8)
M—Te2ii	2.9251 (6)	Te1—Mvi	2.9446 (8)
M—Te2iii	2.9251 (6)	Te1—Mvi	2.9446 (8)
M—Te2iv	2.9251 (6)	Te2—Te2vii	2.7448 (13)
M—Te1v	2.9446 (8)	Te2—Mviii	2.9251 (6)
M—Te1vi	2.9446 (8)	Te2—Mviii	2.9251 (6)
M—Te3	2.9498 (7)	Te2—Mix	2.9251 (6)
M—Te3vii	2.9498 (7)	Te2—Mix	2.9251 (6)
Te1—Mv	2.9446 (8)	Te3—Te3v	2.9129 (9)
Te2i—M—Te2ii	55.96 (3)	Te2iv—M—Te3vii	83.583 (16)
Te2i—M—Te2iii	110.88 (3)	Te1v—M—Te3vii	67.683 (15)
Te2ii—M—Te2iii	85.19 (2)	Te1vi—M—Te3vii	67.683 (15)
Te2i—M—Te2iv	85.19 (2)	Te3—M—Te3vii	118.27 (3)
Te2ii—M—Te2iv	110.88 (3)	Mv—Te1—Mv	0.000 (18)
Te2iii—M—Te2iv	55.96 (3)	Mv—Te1—Mvi	84.50 (3)
Te2i—M—Te1v	151.040 (16)	Mv—Te1—Mvi	84.50 (3)
Te2ii—M—Te1v	151.040 (16)	Mv—Te1—Mvi	84.50 (3)
Te2iii—M—Te1v	87.986 (16)	Mv—Te1—Mvi	84.50 (3)
Te2iv—M—Te1v	87.986 (16)	Mvi—Te1—Mvi	0
Te2i—M—Te1vi	87.986 (16)	Te2vii—Te2—Mviii	62.019 (13)
Te2ii—M—Te1vi	87.986 (16)	Te2vii—Te2—Mviii	62.019 (13)
Te2iii—M—Te1vi	151.040 (16)	Mviii—Te2—Mviii	0.00 (2)
Te2iv—M—Te1vi	151.040 (16)	Te2vii—Te2—Mix	62.019 (13)
Te1v—M—Te1vi	84.49 (3)	Mviii—Te2—Mix	85.19 (2)
Te2i—M—Te3	133.927 (10)	Mviii—Te2—Mix	85.19 (2)
Te2ii—M—Te3	83.584 (16)	Te2vii—Te2—Mix	62.019 (13)
Te2iii—M—Te3	83.583 (16)	Mviii—Te2—Mix	85.19 (2)
Te2iv—M—Te3	133.927 (10)	Mviii—Te2—Mix	85.19 (2)
Te1v—M—Te3	67.683 (15)	Mix—Te2—Mix	0.00 (2)
Te1vi—M—Te3	67.683 (15)	Te3v—Te3—Te3vi	85.63 (3)
Te2i—M—Te3vii	83.583 (16)	Te3v—Te3—M	108.74 (3)
Te2ii—M—Te3vii	133.927 (10)	Te3vi—Te3—M	108.74 (3)
Te2iii—M—Te3vii	133.927 (10)

M = Hf or Ti

M—Te2i	2.9251 (6)
M—Te1ii	2.9446 (8)
M—Te3	2.9498 (7)

Te3ii—Te3—Te3iii

85.63 (3)

Symmetry codes: (i) ; (ii) ; (iii) .