Zero Source Contact Mass Spectral Analysis of Isotopically Labeled Tetraboranes

Abstract

The mass spectra of "B4H10, "B4Dl0, specifically labeled *Bl0B3Hlo, and p-loB4H9D have been obtained under zero ion source contact conditions using a specially designed mass spectrometer and compared with spectra obtained previously on conventional spectrometers. In the latter case there are significant contributions to the spectra from neutral species formed by pyrolysis of tetraborane in the ion source, which acts as a flow reactor. A parent peak and several new metastable transitions have been observed in the zero source contact spectra. Analysis of an IlBlabeled tetraborane, *Bl0B3Hlo, has shown that the BlH,+, B*H,+, and B3H,+ fragment ions are formed in part by nonrandom dissociation processes of the B4Hz+ framework. A reinvestigation of the process by which hydrogen atoms are lost leading to the formation of B4H,+ ions does not appear to support the earlier proposed specific fragmentation scheme. The reaction of nB,De with nB,Hlo at 45' has been reinvestigated using nmr and gas volumetric techniques. No evidence for specific deuterium labeling is found. Pentaborane was formed.he mass spectrum of tetraborane-I0 has been re-

Mass Spectrometric Investigation of the Pyrolysis of Boranes. Tetraborane(10)1

“…While pentaborane has been observed in a mass spectrum of tetraborane taken on a conventional (cycloidal) spectrometer, no "shutterable" pentaborane was observed in a spectrum of the same sample taken on the mass spectrometer used in this experiment. 29 A related phenomenon was observed in this experiment. Before the furnace heating filaments were turned on, only trace amounts of boranes other than tetraborane were observed.…”

Simple, Green, and High‐Yield Production of Boron‐Based Nanostructures with Diverse Morphologies by Dissolution and Recrystallization of Layered Magnesium Diboride Crystals in Water

“…The weak signal observed at m / z= 44 is attributed to tetraborane(4) in its ionic form (i.e. B 4 H 4 + ) . The strong signals observed at m / z= 30 and 42 along with the other weak signals are likely attributed to the fragments derived from B 4 H 4 + , which has a native tendency to undergo fragmentation due to metastable transitions during GC–MS analysis, as shown by Norman et al .…”

“…B 4 H 4 + ) . The strong signals observed at m / z= 30 and 42 along with the other weak signals are likely attributed to the fragments derived from B 4 H 4 + , which has a native tendency to undergo fragmentation due to metastable transitions during GC–MS analysis, as shown by Norman et al . We posit that some such possible fragments could be 10 B 4 H 2 + , 11 B 3 H 9 + , 10 B 3 H 12 + , 11 B 2 10 BH 10 + , 11 B 10 B 2 H 11 + , 10 B 4 H + , 10 B 3 H 11 + , 10 B 3 H 10 + , 11 B 3 H 7 + , 10 B 3 H 4 + , 11 B 10 B 2 H 3 + , 11 B 2 10 BH 2 + , 10 B 3 H 2 + , 11 B 10 B 2 H + , 10 B 2 H 10 + , and 11 B 10 BH 9 + .…”

“…B 4 H 4 + ). [57] The strong signals observeda tm/z = 30 and 42 along with the other weak signals are likely attributed to the fragments derived from B 4 H 4 + ,w hich has an ative tendency to undergo fragmentation due to metastable transitions during GC-MS analysis, as shown by Norman et al [57] We posit that some such possible fragments could be 10 [58] Also, the evolved gases were found to exhibit ac haracteristic foul odor.T ou nderstand the reason behind the formationo fb oron hydrides, we revisited the reactionk inetics of MgB 2 with water.Z hao demonstrated that MgB 2 did not exhibit any visible reaction with water at temperatures < 39 8C. [35] It, however,u nderwent an exothermic reactionw ith water at temperatures !…”

Molecular-beam mass spectra of hexaborane(12) and octaborane(12)

“…The reaction of tetramethylammonium triborohydride with polyphosphoric acid, as previously described in the literature, was used to prepare hexaborane(12).22 Octaborane(12) was prepared by the decomposition of isononaborane (15) sector, Inghram-type mass spectrometer,17'28 modified with a special gas inlet system,17 was used to collect the data.…”