bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalyse Homogène et Hétérogène Comparaison des Deux Processus Lors de L'Hydrogénation de L'éthylène en Présence D'Une Même Espèce Catalytique
Authors: Gosselain P. A. , Hardy J. C. , Simoens G. , Slegers J. , Verbelen R. 
Published: September 2010

AbstractOn a étudié l'hydrogénation de l'éthylène catalysée par un dérivé organométallique du nickel résultant de l'action en phase gazeuse du triéthyl aluminium sur de l'hexanoate de nickel. Ce complexe soluble dans l'hexane est catalytiquement actif en système (gaz/solide) hétérogène et en phase liquide homogène.Un parallélisme est établi entre ces deux modes de réactions : dans les deux cas, l'équation de vitesse est d'ordre 1 en hydrogène et zéro en éthylène et l'énergie d'activation est voisine de 5 kcal mole−1.
Determination by the mass spectrometric knudsen cell method of the dissociation energies of the group IB chalcogenides
Authors: Smoes S. , Mandy F. , Auwera‐Mahieu A. Vander , Drowart J. 
Published: September 2010

AbstractThe dissociation or atomization energies of the following gaseous group IB chalcogenides were determined to be (in kcal/mole1 kcal = 4.184 kJ.):magnified imageThe atomization energies of the remaining subchalcogenides were estimated withDo°,at(M2X)/Do° (MX) = 2.11 ± 0.03, derived from the above results.In addition, the dissociation energies of the molecules CoAu and NiAu were confirmed.
Reactive intermediates and molecular beam mass spectra of the boranes [1]
Authors: Stafford Fred E. 
Published: September 2010

AbstractMolecular beam mass spectrometric work on the lower boron hydrides is reported. Borane, BH3, and tetraborane (8), B4H8, were formed by reactions involving loss of BH3, CO, and, in the latter case, H2 from the appropriate molecules. This ensemble of reactions permitted unambiguous identification of each species. A route to B3H7 from B3H7PX3 is proposed. Investigation of the “stable” and “unstable” boranes and isotopically labelled molecules permits correlations of the mass spectra, determination of a structure ((B4H9)2), and identification of fragmentation pathways. Steady state pyrolysis in the ion source is particularly insidious. Because of it, previous appearance potential and theoretical fragmentation studies of e. g., B4H10 are virtually meaningless.
Free Radicals by Mass Spectrometry XLIV. Ionization Potentials and Bond Dissociation Energies for Chloro‐ and Fluoro‐Methyl Radicals
Authors: Lossing F. P. 
Published: September 2010

AbstractUsing monoenergetic electron impact, ionization thresholds have been re‐measured for chloro‐ and fluoro‐methyl radicals produced in a silica furnace. The following ionization potentials have been obtained (in volts): CH2Cl 8.80, CHCl2 8.45, CCl3 8.28, CH2F 8.90. For CHF2 and CF3, only upper limits were measured. Appearance potentials for halomethyl ions from derivatives have also been measured. From a consideration of these and literature values, best values are proposed for the heats of formation of the radicals and their cations.
Photosensitization by Benzaldehyde in the Gas Phase Part II. Cis‐ and trans‐1, 3‐pentadiene
Authors: Maré G. R. De , Fontaine M‐C. , Huybrechts G. 
Published: September 2010

AbstractThe gas‐phase cis‐trans isomerization of 1, 3‐pentadiene photosensitized by benzaldehyde has been studied at λ = 365.5 nm and 60° in the pressure range 50 to 400 torr. From the observed quantum yields and the photostationary state it can be concluded that benzaldehyde transfers its triplet energy at the same rate to both cis‐ and trans‐1, 3‐pentadiene with high efficiency.
Centrifugal Radial Thin‐Layer Chromatography
Authors: Lepoivre A. 
Published: September 2010

AbstractThe general applicability of centrifugal radial TLC is examined. Large plates (40 × 40 cm) are used for analytical and preparative separations. In addition to the very short time of development, some separations are improved compared to the normal radial developments. The possibilities of direct coupling of gaschromatography with radial TLC are also mentioned.
Association de L'Ion Thiocyanate AVEC Différents Cations Étudiée Par Spectrométrie Infrarouge
Authors: Ménard Mll. C. , Wojtkowiak B. , Chabanel M. 
Published: September 2010

AbstractL'étude infrarouge de solutions de thiocyanates dans des solvants organiques aprotiques a permis d'identifier les paires d'ions de contact LiNCS, NaNCS et MgNCS+. Les déplacements observés sur la bande d'absorption v(C=N) des différentes espèces chimiques sont dus à des effets de constante diélectrique plutǒt qu'à des interactions spécifiques.
Contribution A L'étude des Arséniures de fer, Cobalt et Nickel II. Les Systèmes Ternaires Fe‐Co‐As et Co‐Ni‐As
Authors: Naud J. , Breckpot R. 
Published: September 2010

AbstractIn part I (this Bulletin 80 (1971) 91‐105) the binary systems As‐Fe, As‐Co and As‐Ni were considered. The ternary systems As‐Fe‐Co and As‐Co‐Ni, as obtainable by thermal synthesis at 700° or by precipitation with AsH3, are now studied. The composition range covered is MeAs2‐Me5As2 by thermal synthesis. In this range the Fe‐Co‐As system shows only one cubic variety; this has a Me/As ratio of 1/1,66. By precipitation only nickel can form metal rich derivatives with a ratio Ni/As depending of the pH. In mixed Co+ + +Ni+ + solutions there appears a small selectivity for Ni in the precipitate.This can be markedly increased by submitting arsenides, thermal or precipitated or natural, to electrochemical reduction in contact with mixed Co+ + + Ni+ + solution. Arsenides with NiAs structure gives rise to Ni11As8 and Ni5As2. MnP and monoclinic type arsenides will only react if they contain a small amount of Ni.This favours the superficial déposition of amorphous nickel metal, probably anchored on Ni5As2 nuclei formed in a first step.
Sélénazolidines I. Synthèse de la Sélénazolidine, de N‐Alcoylsélénazolidines et de Leurs Dérivés de Substitution en 2
Authors: Draguet C. , Renson M. 
Published: September 2010

AbstractNous décrivons un méthode générale de synthèse de la sélénazolidine, ainsi que des sélénazolidines substituées dans les positions 2 et 3.
Transition Metal Complexes Containing Ligands of Pharmacological Interest
Authors: Craciunescu D. , Ben‐Bassat A. H. I. 
Published: September 2010

AbstractNicotinamide complexes of the following general composition were prepared: [ML2] [Hgl4], [ML2] [Hg(SCN)4] and ML2(SCN)2, (L = ligand; M  Cu2+, Ni2+, Co2+, Fe2+ and Zn2+). As shown by spectroscopic (IR) results, coordination is achieved by the pyridine nitrogen (C  N), and not by the amidic one (magnified image). The location of the vc‐s and VCN bands supports the existence of a thiocyanatoisothiocyanato isomerism.
Free energy‐, enthalpy‐ and entropy changes of the Ag(I) complexes of ω‐aminosulphonates and ω′‐aminoalkylpyridinium compounds
Authors: Poucke L. C. Van , Thiers G. F. , Eeckhaut Z. 
Published: September 2010

AbstractThe acidity constants of the ω‐aminosulphonates NH2(CH2)SO3− with n = 2, 3,4 and 5 and the stability constants of the Ag(I) complexes of these ligands were determined at 25°, in 0.5 M KNO3. The enthalpy‐ and entropy changes accompanying the formation of the Ag(I) complexes of the same ω‐aminosulphonates and the corresponding ω′‐aminoalkylpyridinium compounds were calculated from calorimetric data. The influence of a negative and of a positive substituent on these thermodynamic functions is briefly discussed.
Radiation Chemistry of 1‐Chloropentane in the Solid Phase II. Influence of Unsaturates
Authors: Ceulemans J. , Claes P. 
Published: September 2010

AbstractThe influence of cyclohexene and 1‐pentene on the yield of the products of the radiolysis of solid 1‐chloropentane has been studied. The observed influence can be explained by an earlier proposed radiolysis mechanism which contains radicalar and ionic reactions.
Configuration et Réactions des Acides 2‐méthyl‐3‐(6‐Méthoxy‐2‐Naphtyl)‐3‐Penténoique et Hexénoïque
Authors: Martin R. H. , Flammang‐Barbieux Monique , Dvolaitzky Maya , Jacques Jean 
Published: September 2010

AbstractLes acides (esters) mentionnés dans le titre et les dérivés saturés correspondants ont été étudiés par spectrographie de RMN‐1H.
Cations Aromatiques Séléniés I. Perchlorates de 1‐Benzothiéno Sélénopyrylium
Authors: Tadino A. , Christiaens L. , Renson M. , Cagniant P. 
Published: September 2010

AbstractDans le cadre de l'étude de l'action des réactifs nucléophiles sur les perchlorates de sélénopyrylium, nous décrivons la synthèse des perchlorates de 1‐benzothiéno (3,2‐b) et (2,3‐b) sélénopyrylium. Ces composés relativement stables ont été caractérisés notamment par leurs spectres de RMN et UV. Leur réactivité sera décrite ultérieurement.
A New Synthesis of 1,1‐Dichloromethylketones
Authors: Coppens W. , Schamp N. 
Published: September 2010

AbstractA new synthesis of 1, 1‐dichloromethylketones is described. Methylketones are converted into cyclohexylketimines, which by N‐chlorosuccinimide are chlorinated specifically to 1,1‐dichloromethylketimines. Hydrolysis yields 1, 1‐dichloromethylketones, containing less than 5% isomers. Overall yields normally are around 50%.
Réduction de L'Acide Sélénique par le Cuivre en Présence D'Ions Cuivriques
Authors: Ladriere J. 
Published: September 2010

AbstractThe reduction of selenic acid by copper is a very slow reaction, strongly depending on temperature and Cu(II) concentration. Selenic acid is reduced into a non‐stoechiometric selenide : Cu2‐X Se (0 <X <0, 2).The reaction rate is of the first order towards Cu(I) and Se(VI) activities. This is an autocatalytic reaction, one of the products, Cu(II), being able to produce cuprous ions by reaction with metallic copper.
N‐acylamino acids and peptides I. The synthesis of N‐feruloylamino acids
Authors: De Pooter H. , Ali Haider , van Sumere C. F. 
Published: September 2010

AbstractProcedures for the preparation of N‐feruloylglycine (II), ‐DL‐alanine (XX), ‐DL‐valine (XXII) and ‐L‐leucine (XXIV) by classical methods are proposed and compared. The spectral characteristics and Rf‐values of the substances are included. The compounds were synthesized because N‐feruloylamino acids were required as test substances during an investigation in connection with the expected presence of N‐feruloylproteins in barley [1, 2, 3].
Synthèse de Pyrimidines. Étude de la Condensation de L'éthoxycarbonyl‐Dithioacetate de Méthyle Avec Les Amidines. II
Authors: Snyers M. , Donnez M. , Isbecque D. , Lakhanisky T. , Promel R. 
Published: September 2010

Abstract4‐Hydroxy‐6‐mercaptopyrimidines substituted in position 2 by amino‐, methyl‐ or phenyl‐groups are obtained in good yields by “the Principal Synthesis”, using a dithioester as the three‐carbon fragment. The reactions are carried out in dioxane. In ethanol containing sodium ethoxide, the 4‐hydroxy‐6‐mercaptopy‐rimidines are produced in low yields along with small amounts of the corresponding 4‐ethoxy‐6‐hydroxypyrimidines. The mass spectra of the pyrimidine derivatives have been recorded. Their major fragmentations are considered.
Synthèse de 4‐Arylsulfonyloxypyrimidines
Authors: Gubin J. , Durant N. , Nasielski‐Hinkens R. , Prorael R. 
Published: September 2010

AbstractThe reaction of p‐toluenesulfonyl chloride with a few alkyl substituted 4‐hydroxypyrimidines (1a through 1d) yields the corresponding 4‐p‐toluenesulfonyloxypyrimidines (2a through 2d). The structure of the products is based on IR and NMR data. In the case of 4‐hydroxy‐6‐methylpyrimidine (1b), a ring‐opened compound was also isolated to which structure 3 was assigned. 3‐Hydroxy‐6‐methylpyridazine (4) undergoes as well O‐sulfonylation.
Les Nitrates Basiques Mixtes et Hydroxydes Mixtes de Nickel et de Cobalt
Authors: Mannoorettonnil M. , Glibert J. 
Published: September 2010

AbstractThe basic nickel and cobalt nitrates, obtained by addition of soda to Ni(NO3)2 or Co(NO3)2 solutions (O, 2 M Me++/1), have respectively the compositions 4 Ni(OH)2.Ni(OH)0, 75(NO3)1, 25 (I) and 4 Co(OH)2.Co1, 25(OH)1.0(NO3)1, 5 (II. They are unstable and tend to transform into hydroxydes by aging or increase of temperature.In solutions of Ni++ + Co++, at 20°C, precipitation of mixed basic nitrates occurs first and the distribution curve (Ni++/Co prec. as a function of Ni++/Co++ final sol.) shows a change of slope at the transition from basic salt II into I. By prolonging the reaction time, the mixed basic nitrates with predominant presence of cobalt transform into Co1‐xNix (OH)2 while in the nickelrich range, the mixed basic nitrate 5 Ni1‐yCoy(OH)8, 75(BO3)1, 25 (1) is maintened because of the Ni/Co substitution process. A demixing zone separates these two solid solutions.At 75°C, simply the mixed hydroxydes of nickel and cobalt are formed.
N.M.R. Experiments On Acetals. Part 44. The conformational behaviour of 4‐vinylgroups in 1, 3‐dioxanes. 300 MHz Study of 4‐Vinyl‐5‐Me‐, and 4‐Vinyl‐6‐Me‐substituted 1,3‐Dioxanes
Authors: Anteunis M. , Coryn M. 
Published: September 2010

AbstractQuantitative conformational data for a 4‐vinyl group in the 1, 3‐dioxane system are obtained trough a study of the conformational behaviour of both trans substituted 4‐vinyl‐6‐methyl‐1, 3‐dioxanes and cis substituted 4‐vinyl‐5‐methyl‐1, 3‐dioxanes. Some appropriate anan co meric model compounds have been prepared. The results were obtained both by a 300 MHz 1H‐NMR spectroscopic study and by epimerisation studies. δG°(4‐vinyl) may be estimated at 2.25 Kcal/mole.
Minimization of a Function to Determine Stability Constants of Complex Species ‐ a Computer Version
Authors: Robbrecht R. , Steyaert H. , Thun H. P. 
Published: September 2010

AbstractA detailed description is given of a method to minimize a function by computer. This technique was applied to the titration data of bivalent metal‐itaconate complexes, and made it possible to identify the existing complexes, and to calculate their stability constants with their related statistical errors.
Calculation of Detection Limits in Spectrographic Analysis
Authors: Broekaert J. A. C. 
Published: September 2010

AbstractMethods to calculate detection limits of spectrographic techniques in terms of blank and background are described. Detection limits of “point‐to‐plane” and “plane‐to‐plane” spark excitation for spectrographic determination of Yttrium in solution are compared. The influence of electrode shape and of CsCl‐carrier addition is discussed.
NMR Experiments on Acetals. 40. Long Range Phenomena. 15. Some F, H long‐range phenomena, configurational and conformational aspects from the 300 MHZ NMR spectra of 2‐cf3‐4‐(chloro) methyl‐1, 3‐dioxolanes
Authors: Anteunis M. , van Cauwenberghe R. , Beou Chr. 
Published: September 2010

Abstract300 MHz spectra are obtained for cis‐, and trans‐2‐trlfluoromethyl‐4‐(chloro) methyl‐1, 3‐dioxolanes. A comparative study with other 2, 4‐disubstituted and 2, 2‐bis trifluoromethyl trisubstituted dioxolanes, allows the assignment of each of the H‐5 atoms. From the extracted spectral parameters typical conformations may be advanced for the CF3‐substituted 1, 3‐dioxolanes.Some “anomalous”5J (F, H) couplings across oxygen, also observed in 1, 3‐dioxanes, are discussed.
The Leaching of β Cu3, 0As by Oxygen in Concentrated Sulphuric Acid Solutions
Authors: Dewalens J. , Heerman L. , van Simaeys L. 
Published: September 2010

AbstractThe leaching of β Cu3.0 As by oxygen in concentrated sulphuric acid solutions was investigated. Copper is oxidized selectively in solutions containing 1000 g/l H2SO4 at 100 – 140°C with formation of elemental arsenic in the residue.
Highly Specific One‐Step Synthesis of Olefins Deuterium Labelled in Both Allylic Positions, of ENDO, ENDO‐5,6‐Dideuterionorbornene and of 3,5‐Dideuterionortricyclene
Authors: Platbrood G. , Wilputte‐Steinert L. 
Published: September 2010

AbstractThe photoinduced deuteriation of conjugated dienes catalyzed by chromium carbonyl complexes, allows specific labelling in allylic positions.
Spectrométrie de Masse de Pyrazoline‐5‐Ones N1 Substituées. II. 2‐Pyrazoline‐5‐Ones A Structure Fixe et Pyrazoline‐5‐ones Tautomérisables.
Authors: Maquestiau A. , van Haverbeke Y. , Bruyere A. 
Published: September 2010

AbstractThe behaviour under electron impact of fixed 2‐pyrazolin‐5‐ones has been investigated. The main decomposition pathway of these compounds is characteristic of their isomeric structure. The fragmentation pattern of tautomeric N1. substituted pyrazolin‐5‐ones must be interpreted in term of CH form; this suggest that this form prevailes in the gas phase. This result has been verified by I. R. for 1,3‐ and 1,4‐dimethylpyrazolin‐5‐one.
Possible determination of isomerization modes probabilities by A multiple resonance method
Authors: WILLEM R. , Verdin P. , Brocas J. 
Published: September 2010

AbstractWe show that multiple resonance is a possible tool to determine relative probabilities of isomerization modes in the MA4B ligand partition of the trigonal bipyramid. Distinguishability criteria are derived. The scope and limitations of the method are discussed.
Reaction between maleic anhydride and pyrocatechol in the solid‐state
Authors: Singh N. B. , Singh H. N. 
Published: September 2010

AbstractKinetics of the reaction between maleic anhydride and pyrocatechol in the solid phase have been studied over a range of temperatures and particle sizes. It is shown that diffusion occurs through surface migration. The nature of interaction has also been investigated using U. V., I. R. and reflectance spectra. It is concluded that charge‐transfer interaction is involved in the formation of the complex. Powder X‐ray diffraction studies show that crystals have tetragonal symmetry.
Brominated phenylalanines
Authors: Anhoury M. L. , Crooy P. , De Neys R. , Eliaers J. 
Published: September 2010

Abstract(3‐(3‐Bromo‐4‐hydroxy‐S‐methoxy‐phenyl)alanine (Ie) exerts a long‐acting antihypertensive effect in rats and dogs : its synthesis and its optical resolution have already appeared in the literature. 1 Ten new mono‐ and polybrominated phenylalanines with hydroxy‐ and/or methoxy‐groups are here described. These unnatural amino‐acide were synthesized by direct bromination, or via the acetamidomalonic esters (V), or via the azlactones (VI) and the corresponding phenylpyruvic acids (VIII).
NMR experiments on acetals. Part 50 (1). The conformation of cis‐bicyclo[6.4.0]‐10,12‐dioxa‐2‐, and 3‐dodecene
Authors: Anteunis Marc , Coryn M. 
Published: September 2010

AbstractThe preferred conformation of cis‐bicyclo[6.4.0]‐10,12‐dioxa‐2‐dodecene is the one having next to the oxygen of the dioxanic moiety an axial substitution (A, figure 2). This unexpected behaviour stays in contrast to that of the isomeric 3‐dodecene and the corresponding saturated dodecane. These facts are rationalized by the conformational pecularities of the octacyclic moieties, imposing their behaviour on the entire ring system, in despite of a strain of at least 2.25 Kcal/mole in the 2‐dodecene derivative.
Étude de la Stéréoisomérie de Quelques Benzylidenebutenolides, Oxazoline‐ et Imidazoline‐5‐Ones
Authors: Maquestiau A. , van Haverbeke Y. , Muller R. N. 
Published: September 2010

AbstractStereoisomerism of some 3‐arylidenebutenolides, 4‐arylideneoxazolin‐ and imidazolin‐5‐ones have been studied by P. M. R. spectroscopy.Structure in which the aryl nucleus is more remote from the cyclic C=O group is favoured.The validity of spectroscopic criteria in structural assignment of compounds with two anisotropic groups is discussed.
Configuration interaction study of the lower‐lying excited states of molecular ions.
Authors: Leclerc J. C. , Guissard‐Galloy C. 
Published: September 2010

AbstractA new computer program, named CIMOL, is proposed for “ab initio” LCAO‐MO‐SCF‐CI calculations on polyatomic molecules. As an example of the program, the study of the lower‐lying excited states of the CH4 ion is presented for three different geometries (C3V, C2V and CS point groups).
Polarity of Hydrogen Bonds on Carbonyl Groups
Authors: Pauwels Herman , Huyskens Pierre 
Published: September 2010

AbstractFrom the dipole moments of the complexes and of the separate compounds the di‐pole increments Δμ were computed which result from the complexation of a series of phenols of increasing acidity with several compounds with a carbonyl group: a ketone, an ester, a carbonate, an ureine and two amides. The computations were made for several possible values of the angle between the C = 0 axis and the direction of the hydrogen bond going from 100° to 140°. For a given proton acceptor Δμ increases when the pKa of the proton donor decreases. The derivatives ‐d Δμ/d pKa increase with the basicity of the donor. The dipole increment Δμ also increases with the complexation constant Kab and with the frequency shift ΔνOH. Both derivatives d Δμ/d log Kab, and d Δμ/d ΔνOH increase when the basicity of the proton acceptor becomes higher. From the Badger‐Bauer equation relations between Δμ and the complexation enthalpy ΔHab are obtained. The evolution of Δμ with increasing energy of the hydrogen bond in the whole range of ΔHab cannot be represented by a linear equation but the curves must show an upwards curvature. From ΔνOH the displacement of the proton is deduced and the corresponding contribution ΔμH in the dipole increment is computed. For a given energy of the bond ΔμH is clearly less important for the O‐H … O = C bonds than for the O‐H … N bonds but the dipole increment due to electron displacements is higher. This last increment is mainly due to the rearrangement of the electron clouds in the proton acceptor.
Mesure des Potentiels Standards du Couple Am(III)/Am(O) Dans L'Eutectique LiCl‐KCl Entre 400 ET 600°C
Authors: Martinot L. , Spirlet J. C. , Duyckaerts G. , Muller W. 
Published: September 2010

AbstractWe have measured the standard potentials of the system Am(III)/Am(O) in the molten LiCl‐KCl eutectic within the temperature range 400–600°C. The cell used was the following.Am/Am(III), LiCl‐KCl/Ag(I), LiCl‐KCl/AgA comparison has been made with previous results obtained for actinides and lanthanides.
The Prins‐Formaldehyde Condensation on Myrcene and Simple Derivatives
Authors: De Smet A. , Anteunis M. 
Published: September 2010

AbstractThe Prins reaction on myrcene gives very complex mixtures. Neater reactions are met with partially reduced myrcenes and chelotropic adducts of myrcene with SO, and hexafluoroacetone. Some of these may be done on preparative scale. The reactivity is the highest on the trisubstituted olefinic bond. The nature of the reaction products were assessed by1H‐NMR spectroscopy.
Reactivity of N‐2‐(1,1‐Dichloroalkylidene) Cyclohexylamines. II
Authors: De Kimpe N. , Schamp N. 
Published: September 2010

AbstractTreatment of N‐2‐(1,1‐dichloroalkylidene) cyclohexylamines with excess sodium methylate in methanol under reflux afforded N‐2‐(1,1‐dimethoxyalkylidene)‐cyclohexylamines, which were hydrolysed to the corresponding 1,1‐dimethoxy‐2‐alkanones. N‐1‐(2,2‐dichloro‐1‐phenylpropylidene) cyclohexylamine on the other hand yielded dehydrochlorination and nucleophilic substitution.
Thioorganic Derivatives of α‐Aminoacids
Authors: Poupaert J. , Bruylants A. 
Published: September 2010

AbstractA reaction scheme is designed in order to prepare thioorganic functional derivatives of α‐aminoacids: imidothioesters, dithioesters, dithioacids and thioamides. The problem of the N‐protecting group in connection with a critical evaluation of the preparation methods is discussed.
Anisotropy of the Oxygen Kα X‐Ray Emission Band From Mg(OH)2, Single Crystals
Authors: Freund F. 
Published: September 2010

AbstractThe 3σ and 1π molecular orbital contributions to the Oxygen Kα emission band of the hydroxyl ion can be separated by making use of the fact that, in the Mg(OH)2 structure, all OH dipoles are oriented parallel to the c‐axis. The O Kα component due with a 1π → 1s transition at 525.5 eV has its maximum intensity parallel to the crystallographic c‐direction [001], while the 3σ→ 1s component is emitted mainly in the zone (hkO), normal to the c‐direction. The 3σ→ 1s component appears to be split due to electron‐proton interaction, exhibiting two maxima at 524.7 and 526.0 eV.