bluuebunny/crossref_metadata_2025 huggingface dataset:
Partial and total anomalous pulmonary venous connection in the fetus: two‐dimensional and Doppler echocardiographic findings
Authors: Valsangiacomo E. R. , Hornberger L. K. , Barrea C. , Smallhorn J. F. , Yoo S.‐J.
Published: August 2003

Objective

Prenatal diagnosis of total (TAPVC) or partial (PAPVC) anomalous pulmonary venous connection in isolation or associated with other cardiac disease is important for appropriate prenatal counseling and perinatal management. We sought to assess the echocardiographic clues to the fetal diagnosis of TAPVC and PAPVC in a cohort of affected fetuses.

Methods

We retrospectively reviewed 29 fetal echocardiograms performed in 16 pregnancies with fetal TAPVC or PAPVC, systematically analyzing heart chamber size, presence of a confluence behind the left atrium or of a vertical vein, and Doppler flow patterns.

Results

Prenatal diagnosis was made at a mean gestational age of 27 ± 7 weeks. TAPVC was found in 11 cases; five cases for each of supracardiac and infracardiac types and one mixed type. PAPVC was diagnosed in five fetuses, four of which had scimitar syndrome. Ten fetuses had an additional major cardiac defect, including hypoplastic left heart syndrome and right atrial isomerism. In three cases the prenatal diagnosis was only made at follow‐up assessment. Among TAPVC cases, visualization of a confluence behind the left atrium (10/11) and a vertical vein (11/11) were the most consistent echocardiographic clues. Dextrocardia and a small right pulmonary artery suggested scimitar syndrome. The diagnosis was confirmed postnatally or at autopsy in 12 cases. In six fetuses with TAPVC and obstruction confirmed postnatally, continuous turbulent flow in the vertical vein and monophasic continuous flow in the pulmonary veins were demonstrated by color and spectral Doppler.

Conclusions

Fetal echocardiography permits prenatal diagnosis of TAPVC or PAPVC. Spectral and color Doppler provide clues to the presence of an obstructed pulmonary venous pathway. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
The role of Doppler studies in predicting individual intrauterine fetal demise after laser therapy for twin–twin transfusion syndrome
Authors: Martínez J. M. , Bermúdez C. , Becerra C. , López J. , Morales W. J. , Quintero R. A.
Published: August 2003

Objective

To investigate the role of Doppler studies in predicting individual fetal demise in patients scheduled for selective laser photocoagulation of communicating vessels (SLPCV) for twin–twin transfusion syndrome (TTTS).

Methods

Doppler studies of the umbilical artery, umbilical vein, ductus venosus, tricuspid valve regurgitation and middle cerebral artery were performed in the donor and recipient twins before and 24 hours after SLPCV. Results were analyzed cross‐sectionally and longitudinally. As multiple comparisons were made, an a priori alpha rejection was set at P < 0.001.

Results

One hundred and ten consecutive patients were available for analysis. Overall fetal survival was 68.6% (151/220) with at least one survivor in 88.2% (97/110) of cases. Absent or reversed end‐diastolic velocity in the umbilical artery of the donor twin was the only preoperative Doppler result predictive of intrauterine fetal demise (IUFD) (10/15, 66.7%, P < 0.001). Postoperatively, reversed flow during atrial contraction in the ductus venosus of the donor twin showed a trend towards prediction of IUFD of this fetus (4/5, 80%, P = 0.007). No other Doppler studies, including the longitudinal analyses, were predictive of IUFD.

Conclusions

Our data suggest that preoperative absent or reversed end‐diastolic velocity in the umbilical artery may be useful in predicting individual fetal demise of the donor twin in TTTS patients scheduled for SLPCV. This may reflect the role of decreased individual placental mass that may be associated with some donor twins. The inability of other Doppler studies to predict individual IUFD may be explained preoperatively by the effect of the interfetal vascular connections on the individual Doppler signals and postoperatively by the effect of surgery or the timing of the assessment. Our findings may be important in patient counseling, in furthering understanding of the disease, and perhaps in improving surgical technique. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of portal vein thrombosis by ultrasound
Authors: Stiller R. J. , Neale D. , Schwartz D. , Laifer S. , Kleinman G.
Published: August 2003

Neonatal portal vein thrombosis (PVT) is a rare condition seen in the setting of thrombophilia or after umbilical vein catheterization. We report a case of fetal PVT with abnormal antenatal ultrasound findings at 27 weeks of gestation. This presented initially as dilation of the intrahepatic umbilical vein. To our knowledge, this is the first reported case evaluated prenatally. Color Doppler ultrasound was valuable in detecting constriction of the vessel with a high‐velocity jet seen past the obstruction site. A discussion of this condition and differential diagnosis is presented. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Randomized controlled trial using low‐dose aspirin in the prevention of pre‐eclampsia in women with abnormal uterine artery Doppler at 23 weeks' gestation
Authors: Yu C. K. H. , Papageorghiou A. T. , Parra M. , Palma Dias R. , Nicolaides K. H. ,   The Fetal Medicine Foundation Second Trimester Screening Group
Published: August 2003

Objective

Pre‐eclampsia, which is a major cause of perinatal and maternal morbidity and mortality, is thought to be due to impaired perfusion of the placenta. There is contradictory evidence that the administration of low‐dose aspirin may provide effective prophylaxis against the subsequent development of pre‐eclampsia. In this study we tested the hypothesis that in women identified as being at high‐risk for pre‐eclampsia, because of impaired flow in the uterine arteries, the prophylactic use of low‐dose aspirin from 23 weeks of gestation can reduce the incidence of pre‐eclampsia.

Methods

We used color and pulsed Doppler to measure the flow in the uterine arteries in 19 950 singleton pregnancies at 22–24 weeks of gestation. Those women exhibiting increased impedance were recruited into a randomized study of aspirin 150 mg per day or placebo. We compared the two groups for the incidence of pre‐eclampsia and the other consequences of impaired placentation.

Results

The screening study identified 844 women (4.2%) as being at high risk of uteroplacental insufficiency. After exclusion and refusal, 560 women were randomly allocated to aspirin 150 mg or placebo per day until 36 weeks' gestation. There were no significant differences between the aspirin and placebo groups in either the incidence of pre‐eclampsia (18% vs. 19%, P = 0.6) or pre‐eclampsia requiring delivery below 34 weeks (6% vs. 8%, P = 0.36). Furthermore, the administration of aspirin did not significantly alter the incidence of preterm delivery (24% vs. 27%, P = 0.46), birth weight below the 5th centile (22% vs. 24%, P = 0.4), perinatal death (3% vs. 1%, P = 0.33) or placental abruption (4% vs. 2%, P = 0.12).

Conclusion

In pregnancies with impaired placentation, as demonstrated by increased impedance to flow in the uterine arteries, the daily administration of 150 mg aspirin after 23 weeks of gestation does not prevent the subsequent development of pre‐eclampsia. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of cephalothoracopagus janiceps disymmetros using three‐dimensional power Doppler ultrasound and magnetic resonance imaging
Authors: Chen C.‐P. , Shih J.‐C. , Shih S.‐L. , Huang J.‐K. , Huang J.‐P. , Lin Y.‐H. , Wang W.
Published: August 2003

We report the prenatal imaging findings of a rare case of cephalothoracopagus janiceps disymmetros diagnosed at 28 weeks' gestation. Two‐dimensional ultrasound and magnetic resonance imaging demonstrated janiceps conjoined female twins with a single fused cranial vault, duplicated cerebra, two faces, four eyeballs, a fused thorax, two hearts, two thoracic spines, eight limbs and polyhydramnios. Three‐dimensional and power Doppler ultrasound established the definitive classification of cephalothoracopagus conjoined twins and displayed the shared circulation between the two separate hearts. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Universal lattice decoding: principle and recent advances
Authors: Mow Wai Ho
Published: August 2003

The idea of formulating the detection of a lattice‐type modulation, such as M‐PAM and M‐QAM, transmitted over a linear channel as the so‐called universal lattice decoding problem dates back to at least the early 1990s. The applications of such lattice decoders have proliferated in the last few years because of the growing importance of some linear channel models such as multiple‐antenna fading channels and multi‐user CDMA channels. The principle of universal lattice decoding can trace its roots back to the theory and algorithms developed for solving the shortest/closest lattice vector problem for integer programming and cryptoanalysis applications. In this semi‐tutorial paper, such a principle as well as some related recent advances will be reviewed and extended. It will be shown that the lattice basis reduction algorithm of Lenstra, Lenstra and Lovász (LLL) can significantly improve the performance of suboptimal lattice decoders such as the zero‐forcing and VBLAST detectors. In addition, new implementation of the optimal lattice decoder that is particularly efficient at moderate signal‐to‐noise ratios will also be presented. Copyright © 2003 John Wiley & Sons, Ltd.
Analysis and realization of a physical CDD system
Authors: Y. Lee William C.
Published: August 2003

The Code Division Duplexing (CDD) system has been developed recently. It is based on using a Code Division Multiple Access (CDMA) scheme on a Time Division Duplexing (TDD) system; the code applied to the CDD system is not the Walsh code, but rather an advanced smart code. In the past, the CDMA scheme can only be used in a Frequency Division Duplexing (FDD) system for cellular operations. But with this smart code applied to CDMA scheme, the CDMA scheme can be used in a TDD system for cellular operations. The smart code together with the TDD system becomes a CDD system. This CDD system can improve the current interference‐limited environment to a noise‐limited environment. In reality, the smart code cannot eliminate the interference entirely. This paper will analyze the anticipated physical CDD system performance based on the characteristics of the smart code. The cross‐correlation value between two codes in a smart code set does impact the overall error probability and the system capacity. The new calculation introduced in this paper can provide a better understanding of the performance of the CDD systems. Copyright © 2003 John Wiley & Sons, Ltd.
Code acquisition of ZCZ‐CDMA systems based on complete complementary codes
Authors: Guo Xiaoxu , Chen Jie , Suehiro Naoki
Published: August 2003

In recent years, a new quasi‐synchronous CDMA (QS‐CDMA) system based on complete complementary codes with zero correlation zones (ZCZ), named ZCZ‐CDMA system, has been proposed. In a ZCZ‐CDMA system, data transmission efficiency can be greatly improved by accurately detecting the multi‐path properties of the communication channel utilizing the unique correlation features of the ZCZ sequence. As for the despreading operation and the code acquisition, the ZCZ‐CDMA system however is more complicated and difficult than the conventional DS‐CDMA systems. In this paper, we discuss the issues of the code acquisition in ZCZ‐CDMA systems, and propose an efficient code acquisition scheme, called two‐stage search (TSS) scheme. In the first stage of the TSS code acquisition scheme, a predictive code phase is coarsely searched, and then a fine search utilizing the unique features of the ZCZ‐sequences is carried out in the second stage. Simulation results show that the proposed scheme achieves better performance in terms of search time and hardware complexity than conventional code acquisition schemes. Copyright © 2003 John Wiley & Sons, Ltd.
Williamson–Hadamard spreading sequences for DS‐CDMA applications
Authors: Seberry Jennifer , Wysocki Beata J. , Wysocki Tadeusz A.
Published: August 2003

Orthogonal bipolar spreading sequences are used in direct sequence code division multiple access (DS‐CDMA) systems for both spectrum spreading and channel separation. The most commonly used sequences are Walsh–Hadamard sequences of lengths being an integer power of 2. A construction based on Williamson's arrays leading to sequences of lengths N≡4 (mod 8) is presented in the paper. Aperiodic correlation characteristics, for example sequence sets of lengths 12–252 are presented. The correlation properties of the sequence sets are later improved using a diagonal modification technique. Copyright © 2003 John Wiley & Sons, Ltd.
Metric transformation for a turbo‐coded DPSK waveform
Authors: Wang Charles C. , Sklar Dean J.
Published: August 2003

The classical turbo‐decoding algorithm is based on the assumption that the input sequence to the decoder has been disturbed by a noise process that has a Gaussian distribution. For a differentially coherent phase shift keying (DPSK) waveform, the output statistics of a differentially coherent demodulator is nonGaussian. When this sequence is fed directly into the turbo decoder, particularly under a fading environment, the mismatch between decoder algorithm assumptions and actual input statistics can result in significant decoder performance degradation. This paper investigates the bit error performance for such a mismatch for the DPSK waveform. Techniques for forming enhanced turbo‐decoding metrics with biased channel side information (CSI) are proposed. Using these new metrics, error performance in fading conditions is shown to improve significantly. Copyright © 2003 John Wiley & Sons, Ltd.
Optimum design criterion and multilevel coding for radio systems over AWGN and Rayleigh fading channels
Authors: Yuan Dongfeng , Zhang Haixia , Wang Chengxiang , Yao Qi , Song Xiaofei , Huber J. B.
Published: August 2003

For the narrow band Wireless Code Division Multiple Access (WCDMA) system, there are some channel coding schemes proposed and applied like Turbo code and convolutional codes. But for the 4G Code Division Multiple Access (CDMA) wideband systems, we have to use new channel coding schemes with high bandwidth efficiency. In this case, multilevel coding (MLC) scheme is easy to map to Multiple Quardrature Amplitude Modulation (MQAM) modulation strategy to be used for 4G, and MLC+MQAM will be a potential channel coding scheme for the error correcting of next generation of mobile systems.

A novel criterion, that is ‘capacity rule’ plus ‘mapping rule’, for the design of the optimum MLC scheme for radio systems over Rayleigh fading channels is proposed in this paper. Based on this theory, a few of key issues related to design an optimum MLC system are investigated. These include a novel optimum design criterion proposed, different mapping strategies, different decoding methods of MLC/MSD and MLC/Parallel Decoding on Levels (PDL) and their performance comparison over Additive White Gaussian Noise (AWGN) and Rayleigh fading channels respectively. Copyright © 2003 John Wiley & Sons, Ltd.
On a space time parallel iterative coding scheme and its performance evaluation
Authors: Hou Jia , Lee Moon Ho
Published: August 2003

This paper proposes a class of space time parallel (STP) iterative coding scheme to combat fading for wireless MIMO systems. In addition to the inner iterations, thesuper iterations(or outer iterations) and symbol interleaved space time coding are employed to achieve additional time diversity and coding gain in fading channel. The numerical and simulation results demonstrate that the STP iterative coding scheme may make use of all the advantages of transmit diversity and time diversity in wireless MIMO systems. In particular, in the case of STP turbo codes, about 1 dB BER enhancement and half calculation time reduction from conventional space time (ST) turbo codes designs are achieved; in the case of low density parity check (LDPC) codes, about 0.8 dB improvement from conventional ST LDPC designs is obtained. Copyright © 2003 John Wiley & Sons, Ltd.
On the performance of truncated type III hybrid ARQ scheme with code combining
Authors: Chen Qingchun , Fan Pingzhi
Published: August 2003

The hybrid automatic repeats request (ARQ) scheme, together with code combining, is an effective way to provide reliable transmission of data packets over noisy channel. In this paper, it is shown that the application of rate‐compatible punctured convolutional (RCPC) codes in truncated type III hybrid ARQ scheme leads to the so‐called composite code combining. In order to illuminate the effect of the involved composite code combining, a new concept, i.e. combined puncturing pattern, is introduced. By state‐diagram analysis, it is revealed that the overall performance of the truncated type III hybrid ARQ with code combining is dependent on both the maximum transmission number and the residual error probability after code combining. By extending the analysis to the convolutional codes whose symbols exhibit different effective signal‐to‐noise ratio owing to the composite code combining, a closed form of the residual error probability of the combined RCPC codes is derived. Based on the combined puncturing patterns, upper and lower bounds on the error performance are derived, together with an approximation method which is shown to be quite satisfactory by numerical and simulation results. Copyright © 2003 John Wiley & Sons, Ltd.
Specific effects and deconvolution in submicrometre EPMA: application to binary diffusion
Authors: Arnould Olivier , Hild François
Published: August 2003

Electron probe (x‐ray) microanalysis (EPMA) is nowadays a classical and well‐established method for qualitative and (semi)quantitative evaluation of the elemental composition of the (near) surface of a sample on the micrometre scale. This technique can be used to determine concentration profiles due to (inter)diffusion in materials at submicrometre resolution if physical and geometrical effects that occur during the measurement process are accounted for. Standard phenomena are usually corrected by commercial software for a homogeneous elemental composition in the analysed area. However, in the case of a diffusion process on a small scale, the composition is no longer homogeneous and the effect of the hemispherical volume of the x‐ray emission on the spatial resolution of the concentration profiles, and consequently on the diffusion coefficients, has to be considered. A radial x‐ray distribution associated with the classical depth distribution, ϕ(z), allows for the definition of a 2D x‐ray emission function for medium to heavy materials. This enables one to study the effect of some geometrical parameters on the measured concentration profile and to propose a method of reconstructing the real weight fraction profile from the measured profile of the x‐ray intensities by using regularized deconvolution algorithms. Copyright © 2003 John Wiley & Sons, Ltd.
Measurement of diffusion coefficients of Ag in YBa2Cu3O7 by the EDXRF technique
Authors: Dogan O. , Ertuǧrul M. , Çevik U. , Bacaksız E. , Tıraşoǧlu E. , Kobya A. I. , Erdoǧan H.
Published: August 2003

The diffusion of Ag in superconducting YBa2Cu3O7 ceramic was studied over the temperature range 700–850 °C by the energy‐dispersive X‐ray fluorescence (EDXRF) technique. For the excitation of silver atoms, an annular Am‐241 radioisotope source (50 mCi) emitting 59.543 keV photons was used. The temperature dependences of Ag diffusion coefficients in grains (D1) and over the grain boundaries (D2) are described by the equations D1 = 1.4 × 10−2exp[−(1.18 ± 0.10)/kT] and D2 = 3.1 × 10−4exp[−(0.87 ± 0.10)/kT]. Copyright © 2003 John Wiley & Sons, Ltd.
Bremsstrahlung spectra produced by 89Sr beta particles in thick targets
Authors: Dhaliwal Amarjit S.
Published: August 2003

External bremsstrahlung spectra produced by hard beta particles of 89Sr (1.463 MeV) in thick targets of Al, Cu, Sn and Pb were studied. After making the necessary corrections, the experimental results were compared with the theoretical external bremsstrahlung distributions obtained from Elwert corrected (non‐relativistic) Bethe–Heitler theory, Tseng and Pratt theory and modified Elwert factor (relativistic) Bethe–Heitler theory. It was found that for low‐Z elements all theories are equally suitable throughout the energy region studied. For medium‐Z elements, the Tseng and Pratt and modified Elwert factor (relativistic) Bethe–Heitler theories are more accurate, particularly in medium and higher energy regions. However, for high‐Z elements, the modified Elwert factor (relativistic) Bethe–Heitler theory shows better agreement with the experiment, particularly at the higher energy end. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of the provenance of medieval silver coins: potential and limitations of x‐ray analysis using photons, electrons or protons
Authors: Linke R. , Schreiner M. , Demortier G. , Alram M.
Published: August 2003

One hundred and fifty seven ‘Tiroler Kreuzer’, a medieval currency from the county of Tyrol/Austria, were analysed in order to determine their place of mintage. The silver coins were produced during the 15th century in the mints of Merano (South Tyrol) and Hall (North Tyrol) but they have no marks or punches which would allow a clear distinction. Energy‐dispersive x‐ray fluorescence analysis (EDXRF) was applied without sampling in order to determine the silver contents and also minor (Cu, Pb, Bi) and trace elements (Fe, Au, Hg, Ni). Owing to corrosion processes, which changed the chemical composition of the surfaces of the coins, investigations of cross‐sections were necessary using energy‐dispersive x‐ray microanalysis in a scanning electron microscope (SEM/EDX) to determine the stage of corrosion and the Ag concentration of the core of the coins. The results showed differences of up to 50% between the composition of the core and the surface. Finally, proton‐induced x‐ray emission (PIXE) at an external proton beam was applied, in order to detect also Ni, an element which could not be measured by either EDXRF or SEM/EDX in the ppm range. The data show a clear difference in the Ni content between the coins from Merano (∼0.1% Ni) and Hall (∼0.01% Ni). Copyright © 2003 John Wiley & Sons, Ltd.
Energies of KαLN x‐ray satellite lines produced in Ca, Ti, Cr and Fe targets bombarded by fast heavy ions
Authors: Kavčič M. , Budnar M. , Dousse J.‐Cl. , Hoszowska J.
Published: August 2003

High‐resolution measurements of the Kα x‐ray spectra of metallic Ca, Ti, Cr and Fe were performed with a von Hamos Bragg crystal spectrometer. The target x‐ray emission was induced by 34, 72 and 134 MeV C ions, 28, 64 and 230 MeV O ions and 43, 160 and 380 MeV Ne ions. The energies of the resolved KαLN x‐ray satellite lines were determined. The possible variation of the energy differences between neighboring KαLN lines with the projectile energy, projectile atomic number and number of target L shell spectator vacancies was probed. No significant dependence on the projectile characteristics was observed. In contrast, the absolute energies of the KαLN satellite lines were found to depend on the projectile velocity. This dependence was attributed to the additional M shell ionization of the target atoms. Copyright © 2003 John Wiley & Sons, Ltd.
Distribution and incorporation of zinc in biological calcium phosphates
Authors: Barrea Raul A. , Pérez Carlos A. , Ramos Aline Y. , Sánchez Héctor J. , Grenón Miriam
Published: August 2003

Human dental calculi are biological calcium phosphates, which consist of an organic phase and an inorganic or mineral phase. In the latter phase, spectrochemical analyses have revealed the presence of several different magnesium and calcium phosphates. As the crystalline structure of the calculus passes through several stages during its allocation in the mouth, special attention is paid to some elements, such as zinc, that can modify the mineralization process. Several in vitro studies relating to the dental calculus mineralization process have been performed so far, but there is a lack of data obtained from biologically synthesized samples. The knowledge of the zinc distribution and incorporation in biological calcium phosphates is of great interest in providing more information about the biological process of calculus formation. In this paper we present surveys of the elemental distribution and incorporation of zinc in human dental calculus, by using a combination of different techniques: x‐ray microfluorescence using synchrotron radiation, scanning electron microscopy and x‐ray absorption spectroscopy. One‐dimensional x‐ray microfluorescence of zinc and magnesium measurement shows that there is a high accumulation of both elements in the sub‐gingival region of the calculus and a strong correlation of their spatial distribution. Experimental Ca/P molar ratios were determined by energy‐dispersive spectroscopy to identify different calcium phosphate phases, the sub‐gingival region being composed of a mixture of highly and poorly calcified phosphates and the supra‐gingival region composed mainly of carbonated hydroxyapatite. Finally, x‐ray absorption measurements were carried out at the zinc K edge on synthetic and biological samples. The Zn—O distance and coordination number of the synthetic samples and the supra‐gingival calculus show that zinc is adsorbed on these structures, whereas in the sub‐gingival samples it is allocated in a cation site. The results are indicative of the active participation of zinc in the calcification process of sub‐gingival calculus. Copyright © 2003 John Wiley & Sons, Ltd.
Energy‐dispersive x‐ray fluorescence analysis of modern coloured glasses from Marinha Grande (Portugal)
Authors: Valério P. , Markowicz A. , Kregsamer P. , Araújo M. F. , de Matos A. Pires , Chinea‐Cano E. , Carvalho C.
Published: August 2003

The elemental composition (K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Ba, Nd and Pb) of modern coloured glasses was obtained by energy‐dispersive x‐ray fluorescence (EDXRF) spectrometry. This non‐destructive technique is frequently used in the analysis of historical glass objects. Two reference glasses were also measured to assess the overall accuracy of the EDXRF method. Reference and unknown glasses were analysed without any preparation. The coloured glass samples studied belong to the Glass Museum of Marinha Grande and were chosen from two distinct collections, which were characterized by the different concentrations of some elements (K, Ti, Cr, Mn, Fe, Ba and Pb). The determined major elements allowed the identification of two raw materials used in glass manufacture, sand and lime. Multivariate statistical analysis, namely principal component extraction, simplified the identification of some of the colouring chemical elements, associating them with the different colours of the glass objects. Copyright © 2003 John Wiley & Sons, Ltd.
Micro‐synchrotron x‐ray fluorescence of the metal distribution in a black spruce tree stem: evidence for radial mobility
Authors: Martin R. R. , Naftel S. J. , Skinner W. , Jones K. W. , Feng H.
Published: August 2003

Micro‐synchrotron radiation x‐ray fluorescence has been used to examine the metal distribution across an entire black spruce stem. The results show the individual elements to be transported and sequestered in different ways so that apparent elemental mobility within the stem changes from element to element. The results suggest that a detailed knowledge of the behavior of each element is required before pollution chronologies can be inferred from dendroanalysis. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis, Crystal Structure, and Electrochemical Behaviour of an Azido μ‐bridged Ni2+ Complex
Authors: Kurtaran Raif , Arici Cengiz , Emregül Kaan C. , Ülkü Dinçer , Atakol Orhan , Taştekin Mustafa
Published: August 2003

A homo‐dinuclear NiII complex was prepared from 2, 6‐bis(3, 5‐dimethylpyrazolyl)pyridine (Me4‐bpp) and azide ions in nonaqueous media. It was characterized by single crystal X‐ray structural analysis, IR spectroscopy, and elemental analysis. In addition, the electrochemical properties of the compound were determined with cyclic voltammetry in DMF. The title compound crystallizes in the P21/n monoclinic space group, with unit cell parameters a = 8.978(1), b = 12.459(1), c = 17.764(1) Å, ß =100.603(3)°, V = 1953.0(3) Å3, Z = 2. The Ni2+ ion has a distorted octahedral environment involving three nitrogen atoms of the Me4‐bpp ligand, two nitrogen atoms from the bridged azide group, and one nitrogen atom from the terminal azide group. The Ni···Ni distance is 3.273(5) Å.
Crystal Structures of [Cu2(bpy)2(H2O)(OH)2(SO4)]·4H2O and [Cu(bpy)(H2O)2]SO4 with bpy = 2, 2′‐Bipyridine
Authors: Zheng Yue‐Qing , Lin Jian‐Li
Published: August 2003

Two sulfato CuII complexes [Cu2(bpy)2(H2O)(OH)2(SO4)]· 4H2O (1) and [Cu(bpy)(H2O)2]SO4 (2) were synthesized and structurally characterized by single crystal X—ray diffraction. Complex 1 consists of the asymmetric dinuclear [Cu2(bpy)2(H2O)(OH)2(SO4)] complex molecules and hydrogen bonded H2O molecules. Within the dinuclear molecules, the Cu atoms are in square pyramidal geometries, where the equatorial sites are occupied by two N atoms of one bpy ligand and two O atoms of different μ2—OH groups and the apical position by one aqua ligand or one sulfato group. Through intermolecular O—H···O and C—H···O hydrogen bonds and intermolecular π—π stacking interactions, the dinuclear complex molecules are assembled into layers, between which the hydrogen bonded H2O molecules are located. The Cu atoms in 2 are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two H2O molecules and two sulfato groups with the sulfato O atoms at the trans positions and are bridged by sulfato groups into 1[Cu(bpy)(H2O)2(SO4)2/2] chains. Through the interchain π—π stacking interactions and interchain C—H···O hydrogen bonds, the resulting chains are assembled into bi—chains, which are further interlinked into layers by O—H···O hydrogen bonds between adjacent bichains.
LiE(SiMe3)2 (E = P, As) als Synthesebaustein zur Darstellung von Molybdänkomplexen mit EH funktionellen Liganden
Authors: Vogel Ulf , Scheer Manfred
Published: August 2003

Der Komplex [{CpMo(CO)2}2(μ‐H)(μ‐PH2)] (1) wird in einer Eintopfreaktion aus [CpMo(CO)2]2, LiP(SiMe3)2, MeOH und HBF4 in guten Ausbeuten erhalten. In einer zur Darstellung von 1 analogen Reaktion ausgehend von LiAs(SiMe3)2 konnten die Verbindungen [{CpMo(CO)2}2(μ, η2‐As2)] und ‐[{CpMo(CO)2}2(μ‐H)(μ4‐As){CpMo(CO)2}2(μ4, η1:η1‐As2H){CpMo(CO)2}2(μ‐H)] (3) isoliert werden. Das deprotonierte Derivat von 1, K[{CpMo(CO)2}2(μ‐PH2)] (2), das mittels Metallierung mit KH gebildet wird, reagiert mit GaCl3 nicht wie erwartet unter KCl‐Eliminierung. Stattdessen bildet sich das Lewis Säure/Base‐Addukt K[{CpMo(CO)2}2(μ‐PH2)(GaCl3)] (4), das im Festkörper eine polymere Kettenstruktur ausbildet. Die spektroskopischen und strukturellen Daten der Produkte werden diskutiert.
Zinc(II), Cadmium(II), and Mercury(II) Complexes with the 2, 2′‐Diamino‐4, 4′‐bithiazole (DABTZ) Ligand — Syntheses and X‐Ray Crystal Structure of [Hg(DABTZ)(SCN)2]
Authors: Morsali Ali , Payheghader Mahmod , Reza Poorheravi Mohammad , Jamali Fahimeh
Published: August 2003

Reaction of the ligand 2, 2′‐diamino‐4, 4′‐bithiazole (DABTZ) with Zn(ClO4)2, CdCl2, and Hg(SCN)2 gives complexes with composition [Zn(DABTZ)2](ClO4)2, [Cd(DABTZ)2Cl2], and [Hg(DABTZ)(SCN)2]. The complexes were characterized by elemental analyses and infrared spectroscopy. The crystal structure of the [Hg(DABTZ)(SCN)2] was determined by X‐ray crystallography. The complex is built up of a monomeric Hg(SCN)2 unit with one 2, 2′‐diamino‐4, 4′‐bithiazole ligand coordinated to the Hg atom via the two N atoms giving rise to a five‐member chelate ring in a distorted tetrahedral environment. There is π‐π stacking interaction between the parallel aromatic rings belonging to adjacent chain as planar species in which the mean molecular planes are close to parallel and separated by a distance of ∼ 3.5Å, close to that of the planes in graphite. The coordinated 2, 2′‐diamino‐4, 4′‐bithiazole molecule is involved in hydrogen bonding acting as hydrogen‐bond donors with N atoms from the SCN ligand as potential hydrogen‐bond acceptors. The hydrogen bonding yields infinite chains parallel to the crystallographic vectors a and b. Each molecule is bonded to three neighbours. Both amine H atoms are hydrogen bonded to N atoms.
A Novel 3D Framework Coordination Polymer based on Succinato bridged Helical Chains Connected by 4, 4' ‐ Bipyridine: [Cu(bpy)(H2O)2(C4H4O4)]?2H2O
Authors: Zheng Yue‐Qing , Kong Zu‐Ping
Published: August 2003

Blue needle—shaped crystals of [Cu(bpy)(H2O)2(C4H4O4)]· 2H2O were obtained by slow evaporation of a methanolic aqueous solution containing a fresh Cu(C4H4O4)· 2H2O precipitate, 4, 4′—bipyridine, and ammonia. Within the complex, the six—coordinated Cu atoms are linked by bis—monodentate gauche succinate anions into chains propagating helically around the [001] axis. The chains are interconnected by 4, 4′—bipyridine ligands into a 3D framework with the crystal H2O molecules located in the channels along the [100], [010] and [110] directions. The Cu2+ ions are in distorted octahedral coordination of two nitrogen and four oxygen atoms (equatorial bonds: Cu—N 1.986(5), 2.015(5)Å; Cu—O 1.950(6), 1.954(6)Å; axial bonds Cu—O: 2.524(9), 2.539(8)Å). Furthermore, the thermal and magnetic behavior of the compound will be discussed. Crystal data: hexagonal, P61 (no. 169), a = 11.066(2)Å, c = 24.965(5)Å, V = 2647.5(8)Å3, Z = 6, R = 0.0528 and wR2 = 0.1103 for 1426 observed reflections (Fo2 > 2σ(Fo2)) out of 2170 unique reflections.
The Combustion of SiCl4 in Hot O2/H2 Flames
Authors: Hannebauer Bernd , Menzel Frank
Published: August 2003

A simple kinetic model describing the molecular gas phase reactions during the formation of fumed silica (AEROSIL®) was developed. The focus was on the formation of molecular SiO2, starting from SiCl4, hydrogen and oxygen. Wherever available, kinetic and thermodynamic parameters were taken from the literature. All other parameters are based on quantum chemical calculations. From these data, an adiabatic model for the combustion reaction has been developed. It was found that a significant amount of molecular SiO2 forms after about 0.1 and 0.6 ms at starting temperatures between 1000 and 2000 K. The initial reaction of the SiCl4 combustion in a hydrogen/oxygen flame was found to be different from the combustion in air: The high reactivity of SiCl4 towards water is favored over the SiCl4 dissociation, which is the initial and rate‐determining step during the combustion of SiCl4 in air.
Photolytically Induced Reaction of Monomeric AlCl with Dihydrogen in a Solid Ar Matrix at 12 K: Generation and Characterization of the Previously Unknown Monomeric Aluminium Hydride ClAlH2
Authors: Himmel Hans‐Jörg , Klaus Christina
Published: August 2003

Monomeric AlCl is shown to react with H2 under photoactivation to yield the new monomeric aluminium hydride ClAlH2. The planar, C2v symmetric molecule is characterized by its IR spectra, taking in the effects of isotopic substitution (H2, D2 and HD), allied with detailed quantum chemical calculations. A normal coordinate analysis is performed to calculate accurate force constants. The properties of this species are compared to the ones of other related compounds featuring either an Al‐H or an Al‐Cl bond. Finally, the dimerization to give the D2h symmetric H2Al(μ‐Cl)2AlH2 is investigated theoretically. This dimer is of interest as a possible reagent to prepare dialane, Al2H6. The enthalpy for the reaction of H2Al(μ‐Cl)2AlH2 in the gas‐phase with solid LiAlH4 to give gaseous Al2H6 and solid LiCl is calculated.
Syntheses, Characterizations, and Crystal Structures of β‐Diketiminato Compounds of Pentafluorophenyl Group 12 Derivatives, HC{[C(Me)N(C6H3‐2, 6‐i‐Pr2)]2}MC6F5 (M = Zn, Cd)
Authors: Aboulkacem Said , Tyrra Wieland , Pantenburg Ingo
Published: August 2003

The reactions of H2C[C(Me)N(C6H3‐2, 6‐i‐Pr2)]2 ((DPP)2NacNacH) and Zn(C6F5)2 · 2 EtCN or Cd(C6F5)2 · 2 MeCN in a molar ratio of approximately 1:1 selectively gave the derivatives (DPP)2NacNacMC6F5 (M = Zn, Cd) in excellent yields. No reaction was observed between (DPP)2NacNacH and Hg(C6F5)2 under similar conditions. Reactions with Hg(C6F5)OCOMe yielded the products of dismutation, Hg(C6F5)2 and Hg(OCOMe)2. (DPP)2NacNacZnC6F5 crystallises as a 1:1 adduct with THF with two independent molecules per unit cell (triclinic, P1 (no. 2)). The zinc atom is tetrahedrally surrounded by the chelating ligand, the pentafluorophenyl group and one THF molecule. A similar situation is found in the 1:1 adduct of (DPP)2NacNacCdC6F5 and DMF (monoclinic, P21/n (no. 14)), while in the donor‐free compound (CDCl3 and H2O co‐crystallize) the cadmium atom is nearly ideally trigonal planar co‐ordinated (orthorhombic, Pbnm (no. 62)).
Ligandstabilisierte cyclische und polycyclische Aluminium‐Phosphor‐ und Aluminium‐Arsen‐Verbindungen
Authors: von Hänisch Carsten
Published: August 2003

Durch Umsetzung von AlCl3 mit Li2AsSiRMe2 (R = CMe2iPr) in einem Gemisch aus Ether und Heptan kann die etherstabilisierte polycyclische Verbindung [(AlCl)4(AsSiRMe2)4(Et2O)2] (4) mit leiterartigem Al4As4‐Grundgerüst erhalten werden. Ihr Aufbau gleicht weitgehend dem der Aluminium‐Phosphorverbindung [(AlCl)4(PSiiPr3)4(Et2O)2] (1), über die kürzlich berichtet wurde [1]. Diese Verbindungen können durch Umsetzung mit Pyridin bzw. NEt3 zu den cyclischen Spezies [{AlCl(C5H5N)}2(PSiiPr3)2] (3) und [{AlCl(NEt3)}2(AsSiRMe2)2] (5) gespalten werden. Die Verbindungen 3, 4 und 5 wurden durch Kristallstrukturanalysen charakterisiert.
Phosphorus Oligomerization in Zintl Phases: Synthesis, Crystal Structure, and Bonding Analysis of Mixed Alkali and Alkaline‐Earth Metal Phosphides
Authors: Derrien G. , Tillard M. , Manteghetti A. , Belin C.
Published: August 2003

Pnictides α‐Ba5P4 and KBa4P5 were prepared by melting the elements. The α‐Ba5P4 compound crystallizes in the orthorhombic system (Sm5Ge4‐type), space group Pnma, Z = 4, a = 8.330(3), b = 16.503(3), c = 8.405(2)Å, it contains two anionic species : P24— dumbbells and P3—. The KBa4P5 compound crystallizes in the tetragonal system, space group P43212, Z = 4, a = 8.559(1), c = 16.102(2)Å, it contains trimers P35— and dumbbells P24—. The crystal structures were solved from single crystal X‐ray data and refined by full‐matrix least‐squares to agreement factors R1 = 0.047 and 0.038, respectively. Using ionic charges, α‐Ba5P4 is formulated as [5Ba2+, 2P3—, P24—] and KBa4P5 as [K+, 4Ba2+, P24—, P35—]. The level of oligomerisation in these structures depends upon the overall valence electron content, bonding within the anionic oligomers has been analyzed on the basis of EHMO calculations and compared to classical or hypervalent bonding in other phosphide compounds.
Syntheses and X‐Ray Structures of μ‐Carbamoyl Complexes of Iron; Isomers of [(CO)3Fe(μ‐Me2NCO)2Fe(CO)2(NHMe2)] with Symmetrical and Asymmetrical Intramolecular NH···O Contacts
Authors: Petz Wolfgang , Neumüller Bernhard , Esser Michael
Published: August 2003

Reaction of the carbamoyl complex [C(NMe2)3][(CO)4FeC(O)NMe2] (1) with silver salts gives the dinuclear μ‐carbamoyl complex [(CO)3Fe(μ‐Me2NCO)2Fe(CO)2(HNMe2)] (2). Depending on the solvent, crystals of 2a with an asymmetrical or of 2b with a symmetrical internal NH···O bridge are formed. The dimethylamino group is originated from a further molecule of 1 from which an amino group is transferred to the “α‐CO” ligand of an intermediate oxidation product while the H+ ion probably comes from deprotonation of a guanidinium cation. The HNMe2 ligand cannot be replaced by CO but easily by PPh3 to give [(CO)3Fe(μ‐Me2NCO)2Fe(CO)2(PPh3)] (3). All complexes were studied by X‐ray diffraction analyses and the usual spectroscopic methods.
Crystal Structure of a CeIII/FeIII Heterobimetallic Complex
Authors: Deacon Glen B. , Forsyth Craig M. , Forsyth Maria
Published: August 2003

A central μ3—O moiety linking two FeIII and one CeIII sites supported by two distinct heterometallic carboxylate bridging modes features in self‐assembled [CeFe2(bpy)2(μ3—O)(μ—L)2(μ—LH)2(LH)(H2O)2]·0.5(bpy)·7H2O (1) (LH2 = glycolic acid), and the structure models potential bonding modes of the Rare Earth corrosion inhibitor Ce(glycolate)3 to iron or iron oxide.
{[2‐FC6H4C(NSiMe3)2Li]4Li2O} — Bildung eines sauerstoffzentrierten Käfigs
Authors: Knapp Carsten , Lork Enno , Mews Rüdiger
Published: August 2003

Aus der Reaktion von [2‐FC6H4C(NSiMe3)2Li]2·OEt2 (1) mit in Toluol vorhandenem Wasser wurde der sauerstoffzentrierte Käfig {[2‐FC6H4C(NSiMe3)2Li]4Li2O} (2) erhalten. Die Bildung des Käfigs, der eine zentrale Li6O‐Einheit enthält, kann mit Hilfe des “laddering principle” erklärt werden.
Polysulfonylamine. CLXIV Kristallstrukturen von Metall‐di(methansulfonyl)amiden. Dithallium‐tris(dimesylamido‐N)argentat: Ein zweidimensionales Koordinationspolymer
Authors: Latorre Violeta , Jones Peter G. , Moers Oliver , Blaschette Armand
Published: August 2003

Die Schichtstruktur des zufällig isolierten Komplexsalzes Tl2[Ag{N(SO2Me)2}3] (monoklin, Raumgruppe P21/n, Z′ = 1) weist zwei neuartige Aspekte auf, nämlich ein (MeSO2)2N—‐Ion, das ungewöhnlich stark von der C2‐symmetrischen Standardkonformation dieser Spezies abweicht und näher an Spiegelsymmetrie heranreicht, und ein Tris(dimesylamido)argentat‐Anion mit trigonal‐planarem AgN3‐Gerüst, Ag—N‐Bindungslängen von 225, 6(6), 226, 0(6) und 236, 3(6) pm sowie N—Ag—N‐Winkeln im Einklang mit dem VSEPR‐Modell [149, 8(2) vs. 102, 8(2) und 107, 3(2)°]. Die unabhängigen Thalliumionen und die komplexen Gegenionen bilden Monoschicht‐Substrukturen, in welchen Tl(1) zu einer (O6)‐, Tl(2) zu einer (O5)‐Umgebung gelangt; die Monoschichten assoziieren sich über einen einzigen unabhängigen Satz von Tl(2)—O‐Bindungen zu Doppelschichten, so daß auch Tl(2) im Endeffekt die Koordinationszahl sechs erreicht. Beide TlO6‐Polyeder entsprechen extrem deformierten Oktaedern, wobei sich in der Winkelverzerrung die stereochemische Aktivität des 6s‐Valenzelektronenpaars zu äußern scheint. Dem zweidimensionalen Ag—N/Tl—O‐Bindungssystem tritt ein dreidimensionales Netzwerk schwacher (C—H···O)‐Wasserstoffbrücken zur Seite.
Cis‐1‐phosphabicyclo[3.3.0]octan
Authors: Krech Friedrich , Krauss Babett , Zschunke Adolf , Mügge Clemens
Published: August 2003

A new approach to 1‐phosphabicyclo[3.3.0]octane compounds starts from the reaction of 4‐chloro‐hepta‐1.6‐diene with Mg in THF. No Grignard rearrangement is observed. The Grignard reagent is converted into 1‐allyl‐3‐butenylphosphonous dichloride followed by reduction with LiAlH4. Cis‐1‐phosphabicyclo[3.3.0]octane has been prepared by radical‐initiated cyclization of 1‐allyl‐3‐butenylphosphane. The bicyclic phosphane is characterized by analytical data as well as 31P and 13C NMR measurements and the reactionswith NO, S8, KSeCN, CH3I, Ni(CO)4 and HSO3F, respectively.
Synthesis, Molecular Structure, and Isomerisation in Solution of (Me3SbS)2Me2SnCl2. Concomitant Hypercoordination of Tin and Antimony
Authors: Beckmann Jens , Dakternieks Dainis , Duthie Andrew , Foitzik Richard C.
Published: August 2003

The reaction of Me3SbCl2 and (Me2SnS)3 afforded the complex (Me3SbS)2Me2SnCl2 in high yields, whose molecular structure features both hypercoordinated tin and antimony atoms. In solution, (Me3SbS)2Me2SnCl2 undergoes a reversible dissociation and ligand interchange reaction to give Me3SbS, Me3SbCl2 and (Me2SnS)3.
Reaktion von Kupferarylen mit Imidazol‐2‐ylidenen oder Triphenylphosphan ‐ Bildung von 1:1‐Addukten mit zweifach koordinierten Kupferatomen
Authors: Niemeyer Mark
Published: August 2003

Die Umsetzung der Kupferaryle CuDmp (Dmp = 2, 6‐Mes2C6H3; Mes = 2, 4, 6‐Me3C6H2) und CuMes mit den σ‐Donoren Triphenylphosphan und 1, 3‐Di‐iso‐propyl‐4, 5‐dimethylimidazol‐2‐yliden führt in Ausbeuten zwischen 65 und 84 % zu den Addukten DmpCu&←PPh3 (1), DmpCu←C{N(iPr)CMe}2 (2) und MesCu←C{N(iPr)CMe}2 (3). Die farblosen Verbindungen wurden durch 1H‐ und 13C‐NMR‐Spektroskopie, Einkristallstrukturanalyse sowie durch 31P‐NMR‐Spektroskopie (1), Elementaranalyse (2), Massenspektrometrie (2, 3), IR‐Spektroskopie (2) und Schmelzpunkt (2, 3) charakterisiert. In den Festkörperstrukturen liegen zweifach koordinierte Kupferatome mit vergleichsweise kurzen Cu—P‐ und Cu—C(Carben)‐Abständen von 218, 91(11) (1), 190, 2(3) (2) und 191, 1(4) pm (3) vor.
Sc2Se3O9: Scandium(III) Oxoselenate(IV) According to Sc2[SeO3]3 with a Hexagonal "Lone‐Pair" Channel Structure
Authors: Wontcheu Joseph , Schleid Thomas
Published: August 2003

The colourless title compound scandium(III) oxoselenate‐(IV) Sc2Se3O9 (≡Sc2[SeO3]3) was obtained by reacting a 1:3‐molar mixture of Sc2O3 and SeO2 at 830°C for seven days in an evacuated torch‐sealed silica vessel as needle‐shaped single crystals. It crystallizes hexagonally (space group: P63/m, Z = 2; a = 814.28(5), c = 764.56(4) pm, c/a = 0.939, Vm = 132.19 cm3/mol, R1 = 0.034 for 364 unique reflections) and exhibits Sc3+ cations in distorted trigonal antiprismatic coordination of six oxygen atoms (d(Sc‐O) = 202 ‐ 220 pm) all of which belong to six different isolated ψ1‐tetrahedral [SeO3]2‐ anions (d(Se‐O) = 166 ‐ 170 pm). In the crystal structure two [ScO6] octahedra share a common face to form a [Sc2O9] dimer (d(Sc···Sc) = 315 pm). The linkage of different dimers occurs only via common vertices with discrete trigonal non‐planar [SeO3]2‐ pyramids and the free non‐bonding electron pairs ("lone pairs") of the Se4+ cations occupy an empty hexagonal channel propagating along the [001] direction.
Novel Zwitterionic Sulfides, Selenides and Tellurides
Authors: Kuhn Norbert , Al‐Sheikh Ahmed , Steimann Manfred , Ströbele Markus
Published: August 2003

The zwitterionic compounds Im‐E‐Mel [9, E = S (a), Se (b), Te (c), Im = 2‐{1, 3‐diisopropyl‐4, 5‐dimethylimidazolium}, Mel = 5‐{2, 2‐dimethyl‐4, 6‐dioxo‐1, 3‐dioxan‐5‐ylide}] are obtained from the corresponding 2‐chalcogeno‐1, 3‐diisopropyl‐4, 5‐dimethylimidazolines 8 and 5‐bromo‐2, 2‐dimethyl‐4, 6‐dioxo‐1, 3‐dioxan (7) in the presence of triethylamine in excellent yields. The crystal structures of the thermally stable compounds reveal most effective charge separations from which the compounds 9 resemble closely to diaryl chalkogenides. 9b and 9c are the first selenocarbonyl and tellurocarbonyl ylides reported, to our knowledge.
Single Crystal Growth and Crystal Structure of Anhydrous Mercury(I) Nitrate, Hg2(NO3)2
Authors: Weil Matthias
Published: August 2003

Polycrystalline anhydrous Hg2(NO3)2 was prepared by drying Hg2(NO3)2·2H2O over concentrated sulphuric acid. Evaporation of a concentrated and slightly acidified mercury(I) nitrate solution to which the same volumetric amount of pyridine was added, led to the growth of colourless rod‐like single crystals of Hg2(NO3)2. Besides the title compound, crystals of hydrous Hg2(NO3)2·2H2O and the basic (Hg2)2(OH)(NO3)3 were formed as by‐products after a crystallization period of about 2 to 4 days at room temperature. The crystal structure was determined from two single crystal diffractometer data sets collected at —100°C and at room temperature: space group P21, Z = 4, —100°C [room temperature]: a = 6.2051(10) [6.2038(7)]Å, b = 8.3444(14) [8.3875(10)]Å, c = 11.7028(1) [11.7620(14)]Å, ß = 93.564(3) [93.415(2)]°, 3018 [3202] structure factors, 182 [182] parameters, R[Fμ2 > 2σ(Fμ2)] = 0.0266 [0.0313]. The structure is built up of two crystallographically inequivalent Hg22+ dumbbells and four NO3— groups which form molecular [O2N‐O‐Hg‐Hg‐O‐NO2] units with short Hg‐O bonds. Via long Hg‐O bonds to adjacent nitrate groups the crystal packing is achieved. The Hg‐Hg distances with an average of d(Hg‐Hg) = 2.5072Å are in the typical range for mercurous oxo compounds. The oxygen coordination around the mercury dumbbells is asymmetric with four and six oxygen atoms as ligands for the two mercury atoms of each dumbbell. The nitrate groups deviate slightly from the geometry of an equilateral triangle with an average distance of d(N‐O) = 1.255Å.