Reaction products from a discharge of N2 and H2S: The microwave spectrum of NH2SH

Thiohydroxylamine has been identified as one of the reaction products from the discharge reaction of N₂ + H₂S. Both cis and trans conformers have been observed. The rotational spectra have been studied from 56 to 170 GHz for the normal species and several deuterated isotopic species of each conformer. The electric dipole moments of both conformers have been determined. A number of the transitions of the cis conformer exhibit splittings due to the nuclear quadrupole moment of the ¹⁴N nucleus. A least squares fit of the frequency splittings have led to an analysis of the eQq values. Ab initio calculations using a 4-31G basis set both with and without polarization functions have been carried out to aid in the analysis and to provide a final structural comparison with the microwave results.     

An isobar model partial-wave analysis of three-body final states in π+p interactions from threshold to 1700 MeV c.m. energy

We present the results of an energy-independent partial-wave analysis of the reaction π⁺p→ππN at nine c.m. energies between 1400 and 1700 MeV. New bubble chamber data from the Cambridge-Imperial College-Westfield College Collaboration were fitted, together with earlier data from Oxford, using the isobar model in a maximum likehood fitting program. The isobars used were Δ(1236), N¹(1470) and ?(770) and allowance was made for an incoherent contribution from an I=2 s-wave phase shift produced by one-pion exchange in the t-channel. The results of this analysis are compared with the predictions of symmetry schemes. The ?₁N amplitudes of the S₃₁ and D₃₃ members of the {70, 1^?} multiplet are clearly observed and their signs unambiguously determined for the first time. Structure in the P₃₁ wave is discussed in relation to recent claims of a low mass resonance. Possible explanations of the complicated behaviour of the P₃₃ wave are discussed; its N¹(1470)π decay is observed for the first time.     

Microscopical identification of water in crystals

Water can exist within solids in many forms : adsorbed on the surface or within micropores, occluded in voids, trapped within a molecular cage as in clathrates, or chemically bonded to species within the crystal lattice. Only in the latter case does it markedly alter the microscopical properties of a crystal. The water molecule possesses an unusually low molecular refraction coefficient. When bound to a crystal, it strongly depresses the principal refractive indices from those of the parent (anhydrous) compound. Examination of optical-crystallographic data from several hundred compounds shows a linear relationship between the per cent water and the mean refractive index for a given series of crystal hydrates. Moisture evolved on heating may be identified by its characteristictemperature and rate of evolution and by other physical and microchemical tests. Hot stage and micro DTA methods are discussed, along with special techniques for the examination of hydrated crystals in the scanning and transmission electron microscopes.     

Double deoxygenation of PPN(NO2) using metal carbonyl clusters of cobalt,rhodium, and iridium

The reaction of PP(NO₂) with M₄(CO)₁₂ (M = Co, Rh) gives the nitrido clusters [M₆N(CO)₁₅]^? in 13 and 21% yields, respectively. A high yield synthesis (77%) of [Rh₆N(CO)₁₅)]^? directly from Rh₆(CO)₁₆ and PPN(NO₂) is also presented. PPN(NO₂) reacts with Ir₄(CO)₁₂ to give the new isocyanato cluster, [Ir₄(NCO)(CO)₁₁]^? in 34% yield, while the direct synthesis of this isocyanate product occurs in 77% yield from PPN(N₃) and Ir₄(CO)₁₂. Modifications of published procedures for the preparation of [N(C₂H₅)₄]₂ [Ir₆(CO)₁₅] and Ir₆(CO)₁₆ are reported that allow shorter reaction times and give higher yields. The reaction of Ir₆(CO)₁₆ with one equivalent of PPN(NO₂) generates a new cluster, PPN[Ir₆(CO)₁₅(NO)], in 57% yield which is proposed to contain a bent nitrosyl ligand. An additional equivalent of PPN(NO₂) gives (PPN)₂[Ir₆(CO)₁₅] in 84% yield with the evolution of N₂O as well as CO₂.     

A report from the Mössbauer effect data center

While interest in Mössbauer spectroscopy has continued at a high level during the last ten years, there is no apparent growth or decline, based on several indicators. It should be noted that there are several trends, both in the areas of who is doing Mössbauer spectroscopy and what topics are being investigated. The Mössbauer Effect Data Center continues to develop its capability of providing the information needs for the community of Mössbauer spectroscopists. New developments at the Center are a continuation of a long history of maintaining a center which is using the most recent available hardware and software capabilities.     

Mixed valence of iron in natural vonsenite

The exchange of electrons between adjacent ions in different oxidation states in vonsenite was observed using Mössbauer spectroscopy. The Mössbauer spectra of a series of naturally occurring vonsenite were recorded over a temperature range of 120–773 K. Four quadrupole doublets were resolved by computer fitting and assigned to Fe²⁺(Fel), Fe²⁺(Fe3), Fe³⁺(Fe2, Fe4) and Fe²⁺-Fe³⁺(Fe2–Fe4). The percentage of iron sites participating in an electron exchange process increases from 17% between 120 and 298 K to 27% between 573 and 773 K.