Reaktionen von Azacoronanden mit Quecksilber(II)iodid: Kristallstrukturen zweier Komplexe von Hgl2 mit Diaza-15-krone-5 und Diaza-18-krone-6 /Reactions of Azacoronands with Mercury(II) Iodide: Crystal Structures of Two Complexes of Hgl2 with Diaza-15-crown-5, and Diaza-18-crown-6

1997 ◽  
Vol 52 (7) ◽  
pp. 847-850 ◽  
Author(s):  
Joachim Pickardt ◽  
Sven Wiese
Keyword(s):  
Bond Length ◽  
Crystal Structures ◽  
Iodine Atom ◽  
Bond Lengths ◽  
The Mean ◽  
Iodide Crystal

The reactions of diaza-15-crown-5 (“2.1”), and diaza-18-crown-6 (“2.2”), resp., with HgI2 in methanol afford the compounds [Hg(2.1)I][Hg2I6] (1) and [Hg(2.2)I][Hg2I6] (2), the crystal structures of which were determined. 1 consists of isolated cations [Hg(2.1)I]+ and anions [Hg2I6]2-. In the cations Hg is coordinated by one iodine atom, the two N atoms and the three O atoms of the ligand; the Hg-I distance is 262.1(3) pm, the Hg-N bond lengths are 221(2) and 238(2) pm; they are significantly shorter than the Hg-O distances, which are in the range between 262 and 271 pm. 2 consists of cations [Hg(2.2)I]+, which are bridged by the anions. In the cations of 2 Hg is coordinated by an iodine atom and by the two N atoms of the ligand, but by only three of the four O atoms. The Hg-I distance is 275.8(5) pm, the mean Hg-N bond length 234(4) pm, and the Hg-O distances vary between 285 and 304 pm. The Hg-I distance to the bridging I atom of the anion is 388.6(6) pm. The Hg-I bond lengths within the anions are slightly widened by this coordination.

New Chalcogenogermanates with Adamantane Type Complex Anions: Preparation and Crystal Structures of K4Ge4S10; Rb4Ge4S10, Rb4Ge4Se10, and Cs4Ge4Se10

1999 ◽  
Vol 54 (12) ◽  
pp. 1499-1504 ◽  
Author(s):  
Kurt O. Klepp ◽  
Ferdinand Fabian
Keyword(s):  
Single Crystal ◽  
Bond Length ◽  
Crystal Structures ◽  
Space Group ◽  
Bond Lengths ◽  
Atomic Arrangement ◽  
Type Complex ◽  
The Mean ◽  
Complex Anions ◽  
Germanium Powder

The title compounds were obtained by reacting stoichiometric quantities of the corresponding dialkalimonochalcogenide, germanium powder and chalcogen at 1073 K. The four compounds are isostructural, crystallizing in space group C2/c, Z = 4 with K4Ge4S10: a = 15.161(3), b = 15.198(2), c = 8.760(2) Å, ß = 105.36(3)°, Rb4Ge4S10: a = 15.282(7), b = 15.341(7), c = 9.061(4) Å , ß = 106.10(3)°; Rb4Ge4Se10: a = 16.095(9), b = 16.09(1), c = 9.390(7) Å , ß = 105.79(2)° and Cs4Ge4Se10: a = 16.348(9), b = 16.49(1), c = 9.771(3) Å, ß = 107.10(3)°. Their crystal structures were solved and refined from single crystal diffractometer data (MoKα radiation) obtained at 294 K. They are characterized by the formation of discrete adamantanelike complex anions [Ge4Q10]4- which are arranged in slabs parallel to (010). Mean Ge-S bond lengths are 2.202 A for K4Ge4S10 and 2.186 Å for Rb4Ge4S10 while the mean Ge-Se bond length in both selenides amounts to 2.332(3) Å. Terminal and bridging Ge-Q bonds differ by at least 0.1 Å. The atomic arrangement corresponds to that of Tl4Ge4S10.

Bond lengths in organic and metal-organic compounds revisited: X—H bond lengths from neutron diffraction data

2010 ◽  
Vol 66 (3) ◽  
pp. 380-386 ◽  
Author(s):  
Frank H. Allen ◽  
Ian J. Bruno
Keyword(s):  
Bond Length ◽  
Data Availability ◽  
General Level ◽  
Mean Values ◽  
Bond Lengths ◽  
Transition Metal Hydrides ◽  
Order Of Magnitude ◽  
Metal Organic ◽  
Structural Database ◽  
The Mean

The number of structures in the Cambridge Structural Database (CSD) has increased by an order of magnitude since the preparation of two major compilations of standard bond lengths in mid-1985. It is now of interest to examine whether this huge increase in data availability has implications for the mean bond-length values published in the late 1980s. Those compilations reported mean X—H bond lengths derived from rather sparse information and for rather few chemical environments. During the intervening years, the number of neutron studies has also increased, although only by a factor of around 2.25, permitting a new analysis of X—H bond-length distributions for (a) organic X = C, N, O, B, and (b) a variety of terminal and homometallic bridging transition metal hydrides. New mean values are reported here and are compared with earlier results. These new overall means are also complemented by an analysis of X—H distances at lower temperatures (T ≤ 140 K), which indicates the general level of librational effects in X—H systems. The study also extends the range of chemical environments for which statistically acceptable mean X—H bond lengths can be obtained, although values from individual structures are also collated to further extend the chemical range of this compilation. Updated default `neutron-normalization' distances for use in hydrogen-bond and deformation-density studies are also proposed for C—H, N—H and O—H, and the low-temperature analysis provides specific values for certain chemical environments and hybridization states of X.

P3Se4I: 5-Iodo-2,3,6,7-tetraselena-1,4,5-triphosphabicyclo[221]heptan, ein neues Phosphorselenaiodid / P3Se4I: 5-Iodo-2,3,6,7-tetraselena-1,4,5-triphosphabicyclo[221]heptan, a New Phosphorus Selena Iodide

1987 ◽  
Vol 42 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Roger Blachnik ◽  
Willi Buchmeier ◽  
Claudia Schneider ◽  
Ulrike Wickel
Keyword(s):  
Bond Length ◽  
Nmr Spectra ◽  
Lattice Parameters ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

P3Se4I is formed by the reaction of molten P4Se3 and I2. P3Se4I is monoclinic, space group P21/c with the lattice parameters of a = 1130.3(3) pm, b = 654.5(2) pm, c =1420.5(4) pm, β - 117.64(2)°. d = 3.87 g cm-3 and dx = 3.82 g cm-3 for Z = 4. The structure of the molecule is derived from the structure of α-or β-P4Se3I2 by the substitution of a P−I group by a Se-atom. The P−I, P−P and Se−Se bond lengths are 249.9, 219.2 and 236.9 pm. resp. The mean P−Se bond length is 225.0 pm. The molecule is stabilized by two weak intramolecular P−Se and P−I bonds, comparable to the bonding situation in α-P4Se3I2 . The 31P NMR spectra reveal a coalescence effect, due to equilibrium between two isomeric forms of the molecules.

scholarly journals Bond-length distributions for ions bonded to oxygen: alkali and alkaline-earth metals

2016 ◽  
Vol 72 (4) ◽  
pp. 602-625 ◽  
Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne
Keyword(s):  
Metal Ions ◽  
Bond Length ◽  
Coordination Number ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Coordination Polyhedra ◽  
Coordination Numbers ◽  
Bond Lengths ◽  
Alkaline Earth Metal Ions ◽  
The Mean

Bond-length distributions have been examined for 55 configurations of alkali-metal ions and 29 configurations of alkaline-earth-metal ions bonded to oxygen, for 4859 coordination polyhedra and 38 594 bond distances (alkali metals), and for 3038 coordination polyhedra and 24 487 bond distances (alkaline-earth metals). Bond lengths generally show a positively skewed Gaussian distribution that originates from the variation in Born repulsion and Coulomb attraction as a function of interatomic distance. The skewness and kurtosis of these distributions generally decrease with increasing coordination number of the central cation, a result of decreasing Born repulsion with increasing coordination number. We confirm the following minimum coordination numbers:[3]Li+,[3]Na+,[4]K+,[4]Rb+,[6]Cs+,[3]Be2+,[4]Mg2+,[6]Ca2+,[6]Sr2+and[6]Ba2+, but note that some reported examples are the result of extensive dynamic and/or positional short-range disorder and are not ordered arrangements. Some distributions of bond lengths are distinctly multi-modal. This is commonly due to the occurrence of large numbers of structure refinements of a particular structure type in which a particular cation is always present, leading to an over-representation of a specific range of bond lengths. Outliers in the distributions of mean bond lengths are often associated with anomalous values of atomic displacement of the constituent cations and/or anions. For a sample of[6]Na+, the ratioUeq(Na)/Ueq(bonded anions)is partially correlated with 〈[6]Na+—O2−〉 (R2= 0.57), suggesting that the mean bond length is correlated with vibrational/displacement characteristics of the constituent ions for a fixed coordination number. Mean bond lengths also show a weak correlation with bond-length distortion from the mean value in general, although some coordination numbers show the widest variation in mean bond length for zero distortion,e.g.Li+in [4]- and [6]-coordination, Na+in [4]- and [6]-coordination. For alkali-metal and alkaline-earth-metal ions, there is a positive correlation between cation coordination number and the grand mean incident bond-valence sum at the central cation, the values varying from 0.84 v.u. for[5]K+to 1.06 v.u. for[8]Li+, and from 1.76 v.u. for[7]Ba2+to 2.10 v.u. for[12]Sr2+. Bond-valence arguments suggest coordination numbers higher than [12] for K+, Rb+, Cs+and Ba2+.

Über die Reaktion von Bis(t-butylamino)dimethylsilan mit Titantetrachlorid. Kristallstrukturen des Imido-Komplexes [TiCl2(N-CMe3)(H2 N-CMe3)(CH3CN)]2 und des Ketimido-Komplexes [TiCl3 {NC(Me)N(H)CMe3}(CH3CN)2]/ On the Reaction of Bis(t-butylamino)dimethylsilane with Titanium Tetrachloride. Crystal Structures of the Imido Complex [TiCl2(N-CMe3)(H2N-CMe3)(CH3CN)]2 and of the Ketimido Complex [TiCl3{NC(Me)N(H)CMe3}(CH3CN)2]

1998 ◽  
Vol 53 (8) ◽  
pp. 887-892 ◽  
Author(s):  
Andreas Mommertz ◽  
Roland Leo ◽  
Werner Massa ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Bond Length ◽  
Crystal Structures ◽  
Titanium Tetrachloride ◽  
Titanium Atom ◽  
Double Bonds ◽  
Dichloromethane Solution ◽  
Bond Lengths ◽  
Monomeric Complex ◽  
Structure Determinations

Abstract The reaction of bis(t-butylamino)dimethylsilane with titanium tetrachloride in dichloromethane solution leads to a mixture of compounds from which the imido complex (H3NCMe3)2[TiCl3(N-CMe3)]2 (1) and by extraction of the residue with acetonitrile the imido complex [TiCl2(N-CMe3)(H2N-CMe3)(CH3CN)]2 (2) can be isolated. 1 reacts with acetonitrile to give the ketimido complex [TiCl3{NC(Me)N(H)CMe3}(CH3CN)2] (3). According to crystal structure determinations 2 consists of centrosymmetric dimeric molecules containing TiCl2Ti bridges, the N-CMe32- ligands being in equatorial positions with TiN bond lengths of 168.8(4) pm which corresponds to double bonds. In the monomeric complex 3 the chloro ligands are in meridional positions of the distorted octahedrally coordinated titanium atom with a TiN bond length of 175.7(2) pm of the ketimido ligand.

The Crystal Structure of KAlP2O7

1973 ◽  
Vol 51 (16) ◽  
pp. 2613-2620 ◽  
Author(s):  
Hok Nam Ng ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Spherical Shell ◽  
Bond Length ◽  
Least Squares ◽  
Least Squares Method ◽  
Full Matrix ◽  
Bond Lengths ◽  
The Mean ◽  
R Value ◽  
Oxygen Atoms

KAlP2O7 crystallizes as monoclinic crystals with a = 7.308(8), b = 9.662(6), c = 8.025(4) Å, β = 106.69(7)°, z = 4 and space group P21/c. The structure was refined from 1394 observed reflections by full-matrix least-squares method to a final R value of 0.032. The P2O74− anion consists of a pair of corner-sharing PO4 groups in a nearly staggered configuration. The mean bridging and terminal P—O bond lengths are 1.607 and 1.509 Å, respectively, and the P—O—P angle is 123.2°. The anions lie in planes parallel to (001). The Al ions are bonded to six oxygen atoms contributed by anions in three layers of P2O7 groups. The average Al—O bond length is 1.889 Å. The potassium ion is coordinated to ten oxygen atoms lying within a spherical shell with inner and outer radii of 2.739 and 3.185 Å.

Torsional vibration and central bond length of N-benzylideneanilines

2004 ◽  
Vol 60 (5) ◽  
pp. 578-588 ◽  
Author(s):  
Jun Harada ◽  
Mayuko Harakawa ◽  
Keiichiro Ogawa
Keyword(s):  
Temperature Dependence ◽  
Bond Length ◽  
Crystal Structures ◽  
Torsional Vibration ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Static Disorder ◽  
X Ray ◽  
Bond Lengths ◽  
Central Bond

The crystal structures of N-benzylideneaniline (1), N-benzylidene-4-carboxyaniline (2), N-(4-methylbenzylidene)-4-nitroaniline (3), N-(4-nitrobenzylidene)-4-methoxyaniline (4), N-(4-nitrobenzylidene)-4-methylaniline (5), N-(4-methoxybenzylidene)aniline (6) and N-(4-methoxybenzylidene)-4-methylaniline (7) were determined by X-ray diffraction analyses at various temperatures. In the crystal structures of all the compounds, an apparent shortening of the central C=N bond was observed at room temperature. As the temperature was lowered, the observed bond lengths increased to approximately 1.28 Å at 90 K, irrespective of substituents in the molecules. The shortening and the temperature dependence of the C=N bond length are interpreted in terms of an artifact caused by the torsional vibration of the C—Ph and N—Ph bonds in the crystals. In the crystal structures of (1) and (7), a static disorder around the C=N bond was observed, which is also responsible for the apparent shortening of the C=N bond.

Group Electronegativities: as Empirically Estimated from Geometrical and Vibrational Data on Sulphones

1979 ◽  
Vol 34 (6) ◽  
pp. 755-760 ◽  
Author(s):  
Istvàn Hargittai
Keyword(s):  
Bond Length ◽  
Empirical Relationships ◽  
Bond Angles ◽  
Bond Lengths ◽  
Bond Stretching ◽  
The Mean

Abstract The S=O bond lengths and the S=O bond stretching frequencies characteristically change with changing ligand electronegativities in the XSO2Y sulphone series. Empirical relationships have been established between the S=0 bond length and the sum of the ligand electronegativities (χX+ χY) and also between the mean stretching frequency and (χX + χY)-These relationships may be used for estimating group electronegativities from geometrical and vibrational data or to predict bond lengths, bond angles and stretching frequencies from ligand electro-negativities.

Crystal structures of rac- and meso-o-Phenylenebis(iodomethylarsine), the latter as its lattice complex with the methiodide of 1,3-Dimethyl-1,3-dihydro-2,1,3-benzoxadiarsole

1977 ◽  
Vol 30 (11) ◽  
pp. 2417 ◽  
Author(s):  
K Henrick ◽  
CL Raston ◽  
AH White ◽  
SB Wild
Keyword(s):  
Charge Transfer ◽  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths ◽  
Iodine Species ◽  
Iodide Anion ◽  
The Mean

The crystal structures of the title compounds, o-C6H4(AsMeI)2 (1), and o- C6H4(AsMeI)2- [o-C6H4(AsMe)(As+Me2)O] I- (2), have been determined at 295 K by single-crystal X-ray diffraction and refined by least squares to residuals of 0.037 and 0.067 for 2095 and 2913 reflections respectively. Crystals of (1) are triclinic, Pī, a 9.865(5), b 9.837(7), c 7.765(4) Ǻ, α 98.89(5), β 96.71(4), γ 60.72(4)�, Z 2. <As- I> is 2.585 Ǻ and <As-C> 1.97 Ǻ. The angles about the arsenic differ only trivially, the mean being 98.4�. Crystals of (2) are monoclinic, P21/n, a 15.315(4), b 21.511(8), c 7.952(2) Ǻ, β 98.19(2)�, Z 4. In the cation As-O distances are unequal [1.75(1) (quaternary As), 1.86(2) Ǻ]; As-O-As is very small being 115.8(8)�. Charge-transfer interactions between iodine species are present in both derivatives; in (2), there is an interaction between the tertiary arsenics of the meso molecule and the iodide anion, As...I being 3.307(3), 3.551(3) Ǻ, with the geometry of the arsenics approaching that of a tetrahedral disposition. Within the cation, the geometry about the quaternary arsenic is typical of arsenic(v), the bond lengths being shorter than those about the ternary arsenic.

Komplexe Chalkogenide der IVa Metalle mit niedrigdimensionalen anionischen Partialstrukturen. Darstellung und Kristallstruktur von K2ZrTe3 und Rb2ZrTe3 / Complex Chalcogenides of the IVa Metals with Low Dimensional Anionic Partial Structures. Preparation and Crystal Structures of K2ZrTe3 and Rb2ZrTe3

1999 ◽  
Vol 54 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Kurt O. Klepp ◽  
Andreas Kolb
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Alkali Cations ◽  
Space Group ◽  
Bond Lengths ◽  
Partial Structures ◽  
Distorted Octahedral ◽  
New Type ◽  
The Mean ◽  
Low Dimensional

The isostructural compounds K2ZrTe3 and Rb2ZrTe3 were obtained at 1000°C by reacting K2Te and Rb2Te with stoichiometric amounts of Zr and Te. The compounds are monoclinic, mP24, space group P21/c, Z = 4 with a = 9.089(3), b = 14.148(4), c = 6.986(3) Å, β = 105.90( 1)° and a = 9.735(4), b = 14.300(7), c = 6.952(8) Å, β = 108.61(2)°, respectively. The crystal structure was determined from diffractometer data and refined to R = 0.030 for 1452 Fo's for K2ZrTe3 and R = 0.038 for 1131 Fo's for Rb2ZrTe3. The crystal structure is of a new type, characterized by infinite anionic chains, 1∞-[ZrTe3]2- built up by octahedra sharing opposite faces which run along [001]. The mean Zr-Te bond lengths are 2.921 and 2.920 Å, respectively. The alkali cations separating the chains are characterized by two different - distorted octahedral and pentagonal bipyramidal - chalcogen environments.

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