A low-temperature X-ray Weissenberg goniometer with closed-cycle cooling to about 28 K

1982 ◽  
Vol 15 (2) ◽  
pp. 241-244 ◽  
Author(s):  
W. Adlhart ◽  
H. Huber
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Single Crystal ◽  
Scattered Radiation ◽  
Angular Range ◽  
Closed Cycle ◽  
Cold Finger ◽  
X Ray ◽  
Crystal Rotation

A low-temperature camera for single-crystal X-ray investigation between 28 and 350 K has been developed for a modified Weissenberg goniometer. Cooling is provided by a double-stage cryorefrigerator which is firmly attached to the low-temperature camera. Stranded copper cables ensure a flexible heat transfer between crystal and cold finger allowing a crystal rotation of 180°. Compared to the usual Weissenberg technique almost no further limitation is given on the accessible angular range of the scattered radiation.

Spin-crossover iron(II) long-chain complex with slow spin equilibrium at low temperature

2021 ◽  
Author(s):  
Qi Zhao ◽  
Jin-Peng Xue ◽  
Zhi-Kun Liu ◽  
Zi-Shuo Yao ◽  
Jun Tao
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Spin Crossover ◽  
Chain Complex ◽  
Mononuclear Complex ◽  
X Ray ◽  
Alkyl Chains ◽  
Long Chain

A mononuclear complex with long alkyl chains, [FeII(H2Bpz2)2(C9bpy)] (1; H2Bpz2 = dihydrobis(1-pyrazolyl)borate, C9bpy = 4,4'-dinonyl-2,2'-bipyridine), was synthesized. Single-crystal X-ray crystallographic studies revealed that - and - forms of the complex...

Backbone Phosphonamide-Functionalized Imidazol-2-ylidene Complexes

2016 ◽  
Vol 69 (10) ◽  
pp. 1186
Author(s):  
Paresh Kumar Majhi ◽  
Gregor Schnakenburg ◽  
Anthony J. Arduengo ◽  
Rainer Streubel
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
X Ray ◽  
Structure Determinations

The synthesis of M(CO)5 complexes bearing 4-phosphonamide and 4,5-bis(phosphonamide)-imidazol-2-ylidene ligands (NHCP = phosphonamide-based N-heterocyclic carbene) is reported. Deprotonation of respective imidazolium hydrogensulfate salts with potassium tert-butoxide (KOtBu) in the presence of [M(CO)5(CH3CN)] afforded complexes with the formula [M(CO)5(NHCP)]. In a similar fashion, reaction of in situ generated NHCP with [Rh(cod)Cl]2 (cod = 1,5-cyclooctadiene) afforded a complex with the formula [Rh(cod)Cl(NHCP)]. Low-temperature deprotonation of the imidazolium NHCP·H2SO4 with potassium hexamethyldisilazide (KHMDS) in the presence of [AuCl(SMe2)] furnished the corresponding AuI NHC complex. All complexes were characterized by various spectroscopic and spectrometric methods. In addition, further structural confirmation is provided by key single-crystal X-ray structure determinations for three of the new complexes.

Aragonite-type lanthanum orthoborate, LaBO3

2006 ◽  
Vol 62 (4) ◽  
pp. i103-i105 ◽  
Author(s):  
Akihiko Nakatsuka ◽  
Osamu Ohtaka ◽  
Hiroshi Arima ◽  
Noriaki Nakayama ◽  
Tadato Mizota
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Single Crystal ◽  
General Position ◽  
Type Structure ◽  
Space Group ◽  
X Ray ◽  
Thermal Vibrations

The crystal structure of the low-temperature (LT) modification of LaBO3 has been redetermined from single-crystal X-ray data; the resulting structure confirms the previous study [Abdullaev, Dzhafarov & Mamedov (1976). Azerbaidzhanskii Khim. Zh. pp. 117–120], but with improved precision. LT-LaBO3 crystallizes in space group Pnma and adopts the aragonite-type structure. Except for one O atom, which is situated on a general position, all other atoms (one La, one B and a second O atom) lie on mirror planes. The structure is composed of LaO9 polyhedra with an average La—O distance of 2.593 Å and trigonal BO3 groups with an average B—O distance of 1.373 Å. Slight anisotropies of the thermal vibrations of La and B atoms suggest that the electrostatic La...La and La...B interactions across the shared edges are weak.

Schwingungsspektren und Normalkoordinatenanalyse von Hexathiocyanatoplatinat(IV), Kristallstruktur von [Py2CH2][Pt(SCN)6] / Vibrational Spectra and Normal Coordinate Analysis of Hexathiocyanatoplatinate(IV), Crystal Structure of [Py2CH2][Pt(SCN)6]

1998 ◽  
Vol 53 (1) ◽  
pp. 13-16
Author(s):  
J. Seemann ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Low Temperature ◽  
Single Crystal ◽  
Vibrational Spectra ◽  
Structure Determination ◽  
Normal Coordinate Analysis ◽  
Normal Coordinate ◽  
X Ray ◽  
Ir And Raman

By treatment of [PtCl6]2- with an excess of SCN– in aqueous solution [Pt(SCN)6]2- is formed. The X-ray structure determination on a single crystal of [Py2CH2][Pt(SCN)6] (orthor-hombic, space group Pna21, a = 15.5084(9), b = 11.8444(11), c = 13.2830(9)Å, Z = 4) shows, that the thiocyanate groups are exclusively S-coordinated with average Pt-S distances of 2.378 Å and Pt-S-C angles in the range from 103.1° to 108.1°. Based on the molecular parameters of the X-ray determination the low temperature (10 K) IR and Raman spectra have been assigned by normal coordinate analysis. The valence force constant is fd(PtS) = 1.62 mdyn/Å.

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