Crystal structures, order-disorder transition and twinning of the Jahn-Teller system (NO)2VCl6
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| 024 | 7 | 0 | |a 10.1524/zkri.218.9.617.20674 |2 doi |
| 035 | |a (NATIONALLICENCE)gruyter-10.1524/zkri.218.9.617.20674 | ||
| 100 | 1 | |a Henke |D Henning | |
| 245 | 1 | 0 | |a Crystal structures, order-disorder transition and twinning of the Jahn-Teller system (NO)2VCl6 |h [Elektronische Daten] |c [Henning Henke] |
| 520 | 3 | |a As in the case of (NO)2TiCl6 the octahedral-shaped crystals of dinitrosonium hexachlorovanadate(IV) are tetragonal at room temperature with space group P4/mnc and Z = 2. An X-ray structure determination at 248 K yields lattice parameters of a = 667.8(1) and c = 1023.8(1) pm, V-Cl distances for the ‘octahedral' VCl62- ion of slightly different length [2 × 233.2(1), 4 × 229.4(1) pm], and a fourfold orientational disorder for the species NO+. The phase change at Tc = 236.5 ± 0.2 K is very sharp and clearly 1st order leading to a monoclinic unit cell with a = 657.1(3), b = 662.6(2), c = 1027.5(2) pm, and β = 91.82(1)° at T = 156 K in space group P21/n with Z = 2. As expected for vanadium in the oxidation state +4 the paramagnetism of the black compound measured above and below Tc confirms the spin-only value for a d1 system. The compressive distortion of the VCl62- units to approximate D4h symmetry [2 × 234.3(1), 2 × 233.7(1), 2 × 224.1(1) pm at 156 K] favours the ordering process of the NO+ cations and vice versa. For the ordered NO+ the atomic distance is 107.0(3) pm. Repetition of the structure analysis at 231 K demonstrates that the static manifestation of the Jahn-Teller effect is coupled to the tilt of the VCl62- groups. In accordance with the symmetry reduction in formally two steps of type t2, the formation of quadruplet domains is observed, usually arranged around [001] as the common axis giving a fourfold rotation twin with ctetr parallel cmon and amon slightly inclined against the tetragonal a-b plane. If the crystal is clamped along c the twin law changes to the corresponding reflection twin (001). | |
| 540 | |a © 2003 Oldenbourg Wissenschaftsverlag GmbH | ||
| 690 | 7 | |a Crystallography |2 nationallicence | |
| 690 | 7 | |a Inorganic chemistry |2 nationallicence | |
| 690 | 7 | |a Organic chemistry |2 nationallicence | |
| 773 | 0 | |t Zeitschrift für Kristallographie - Crystalline Materials |d De Gruyter Oldenbourg |g 218/9(2003-09-01), 617-625 |x 2194-4946 |q 218:9<617 |1 2003 |2 218 |o zkri | |
| 856 | 4 | 0 | |u https://doi.org/10.1524/zkri.218.9.617.20674 |q text/html |z Onlinezugriff via DOI |
| 908 | |D 1 |a research article |2 jats | ||
| 950 | |B NATIONALLICENCE |P 856 |E 40 |u https://doi.org/10.1524/zkri.218.9.617.20674 |q text/html |z Onlinezugriff via DOI | ||
| 950 | |B NATIONALLICENCE |P 100 |E 1- |a Henke |D Henning | ||
| 950 | |B NATIONALLICENCE |P 773 |E 0- |t Zeitschrift für Kristallographie - Crystalline Materials |d De Gruyter Oldenbourg |g 218/9(2003-09-01), 617-625 |x 2194-4946 |q 218:9<617 |1 2003 |2 218 |o zkri | ||
| 900 | 7 | |b CC0 |u http://creativecommons.org/publicdomain/zero/1.0 |2 nationallicence | |
| 898 | |a BK010053 |b XK010053 |c XK010000 | ||
| 949 | |B NATIONALLICENCE |F NATIONALLICENCE |b NL-gruyter | ||