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Assignments of the out-of-plane fundamental modes for D 4 -ortho, meta and para fluorochloro and fluorobromo benzenes are given. A normal coordinate analysis, employing the 94 observed frequencies of the H 4 and D 4 molecules is carried out to obtain a 16-parameter Valence Force Feld, with an average difference of ±1.2% between observed and calculated frequencies. Unique assignments are obtained in the spectra of D 4 -compounds for several of the weak or overlapping bands assigned as fundamentals in the H 4 -compounds.

The infrared and Raman vibrational spectra of X3MCo(CO)4 compounds (M = Si, Ge, Sn and X = Cl, Br, I) including depolarization measurements are presented. These spectra result in complete vibrational assignments which are different from those reported previously.

This study of the vibrational spectra of 2,4-dichloropentane and 2,4,6-trichloroheptane uses normal coordinate calculations as a probe for the presence of different molecular conformers. The calculations use a complete valence force field for secondary chlorides which was developed by fitting the observed vibrational frequencies of model compounds. Observed and calculated frequencies agree well. The results of these calculations on dl and meso 2,4-dichloropentane and on isotactic 2,4,6-trichloroheptane indicate the presence of conformers other than those which are accepted as sterically preferred.

By the application of newer preparative methods and specific organic cations single crystals of polymetallates were obtained of till now unknown structural types. These are salts with polyanions W6O19 2-, W10O32 4-, [HW12O38(OH)2]5-, Mo6O19 2- and HV4O12 3-, furthermore para-tungstates A and B, as well as the compounds [N(CH)3)4]2 Μο8Ο25·5Η2Ο and [N(CH3)4]2Mo10 O31 · 7H2O. The structures of the anions W6O19 2- and W10O32 4- were elucidated by X-Ray analyses; the structure of the Μο6Ο19 2- was derived by vibrational spectroscopy. The knowledge of newer polyanion structures increasingly enables us to gain an insight into the complicated mechanism of oxyhydrate formation by acidification of metal salt solutions.

The compound Me2In(OAc), which is polymeric in the crystalline state, reacts with neutral donor ligands in organic solvents to yield three series of adducts. With monodentate donors, the product is Me2In(OAc)L (L = dimethylsulfoxide or pyridine), which is formulated as a five-coordinate monomer in solution. With bidentate donors, the product is either the monomeric six-coordinate Me2In(OAc)LII (LII = ethylenediamine or 1,2-bis(diphenylphosphino)ethane), or the complex [Me2In(OAc)]2LII (LII = 2,2′-bipyridyl or 1,10-phenanthroline). The n.m.r. and vibrational spectra of these compounds are discussed.

The vibrational spectra of some 1:2 trimethylphosphine adducts of the group IV tetrahalides, which contain ligands in a trans configuration, are examined in detail using perdeutero-trimethylphosphine to facilitate the assignment of all metal–halogen and metal–phosphorus stretching modes. Preparation of SiCl4•2PMe3 with a 1:1 mixture of P(CH3)3 and P(CD3)3 enables an almost unambiguous assignment of the spectrum of this adduct. Normal coordinate calculations for all adducts are reported.

The IR and Raman spectra of SiH3 ⊖, SiH3SiH2 ⊖, (SiH3)2SiH⊖, (SiH3)3Si⊖ and their deuterated derivatives have been recorded in HMPT and HMPT-d18 solutions. Most normal vibrations have been identified. The SiH and SiSi stretching vibrations are considerably lower than for analogous silanes and silylphosphines, ∼ 2050 and 1850-1900 cm-1 being characteristic for SiH3 and SiH⊖ n groups respectively. The assignments are proved by a normal coordinate analysis, and force constants have been calculated. The negative charge is mainly localized on the trivalent Si atom and the lone pair acts repulsively rather than strengthening the SiSi bond through (p→d)π effects.

A vibrational analysis of 9-fluorenone, based upon symmetry information gleaned from polarized infrared and Raman spectra of single crystals, is presented. The fundamental molecular frequencies are quoted from the less perturbed infrared and Raman spectra of solutions which also served to distinguish crystal induced vibrations from the molecular vibrations in the crystal spectra. Raman depolarization ratios of bands obtained in solution and the melt supplemented the polarized crystal data, and were particularly valuable in locating a1 modes.

The reaction of squaric acid, H2C4O4, with the trialkyl derivatives of aluminium, gallium and indium (R3M with R = CH3, C2H5) in a 12 molar ratio leads to bis(dialkylmetal) squarates. The Ga and In compounds dissociate in water forming R2M+ and C4O42− ions. From these solutions the squarates crystallize as mono- and dihydrates, respectively. The vibrational spectra (IR and Raman) are discussed.

Summary The long-standing assignment by Hyams, Bailey and Lippincott 1 of the vibrational spectrum of Mn(CO) 3 (π-C 5 H 5 ) is corrected: the π-C 5 H 5 part of the spectrum cannot be assigned on the basis of C 5ν “local” symmetry, and the a 1 C 3ν ) δ (MnCO) mode is at 668 cm −1 , not 543 cm −1 as previously claimed. New Raman data are given for Mn(CO) 3 (π-C 5 H 4 -CH 3 ) and assigned under C s rules for the ring. C 3ν symmetry is a good approximation for the Mn(CO) 3 moiety.

Tensor autocorrelation functions are calculated taking into account the vibration–rotation coupling effect in Raman scattering spectra of symmetric-top and linear molecules in the gaseous state. A purely quantum-mechanical formalism is used. The theoretical results are given for the ν3 bands of CH3F, OCS, and N2O.

The infrared and Raman spectra of some perovskites with general formula A 3 BB′ 2 O 9 are reported, viz. Sr 3 MgNb 2 O 9 , Sr 3 CaNb 2 O 9 , Pb 3 MgNb 2 O 9 , and Ba 3 Gd 2 WO 9 . The interpretation is by far not as simple as for 1:1 ordered perovskites. Only a rough assignment of the internal modes of the niobate and tungstate octahedra can be made. The spectra of the niobates are very sensitive to the degree of order between the divalent metal ions and the Nb 5+ ions among the smaller cation sublattice. This is evaluated qualitatively.

The infrared spectra of 2-furaldehyde and its deutero analog were measured in the gaseous and liquid states and in solutions. The band contours of the spectra of the gaseous phase were discussed. Normal coordinate calculations were carried out and related to the band assignment.

The preparation, some properties and the vibrational spectra of NMe4 - [Me3TlCN] (I) and NMe4[(Me3Tl)2F] (II) are reported. A C3v point-group can be assigned to the complex anion in (I), whereas in (II) a linear TlFTl-bridged system (symmetry D3h) is present.

The preparation and vibrational spectra of the following complexes are reported: K[R 3 GaF] (R = CH 3 , C 2 H 5 ), NMe 4 [(R 3 Ga) 2 X] (R = CH 3 , C 2 H 5 ; X = F, Cl), NMe 4 [Me 3 GaBr], NMe 4 [(Et 3 Ga) 2 Br].

The mid-infrared, far-infrared, and Raman spectra of 2-cyclopenten-1-one and 2-cyclopenten-1-one-5, 5-d2 have been recorded. Assignments for each of the thirty vibrational fundamentals have been made for the two molecules. Several ring-puckering transitions were observed in the far-infrared spectrum of each molecule. From these were determined potential functions which establish the planarity of the ring system. The potential functions in reduced form derived for the hyride and deuteride are V = 15.0(Z4 + 8.0Z2) cm−1 and V = 14.2(Z4 + 8.8Z2) cm−1, respectively.

Infrared and Raman spectra have been measured of scheelites with formula ALnW8O8, ALnMo2O8 (A = Li, Na, K; Ln = La, Y), Y2MWO8 M = Ge, Si), Y2GeMoO8 and the zircon Y2SiMoO8 in order to get information about the crystallographic order. The A+ and Ln3+ ions in the scheelites ALnW2O8 and ALnMo2O8 are probably ordered in layers Ln-Ln-A-A perpendicular to the c-axis. The order is short-range only. The degree of order decreases in the sequence K, Na, Li. The compounds Y2MWO8 and Y2GeMoO8 are not ordered, whereas the Si4+ and Mo6+ ions in Y2SiMoO8 are ordered in alternate layers perpendicular to the c-axis. The use of vibrational spectra for the determination of crystallographic order is discussed.

The infrared and laser Raman spectra of liquid C 6 H 5 NC and C 6 D 5 NC have been measured and analyzed. Frequencies have been assigned for the 33 normal modes of vibration.

The valence force field and normal modes of vibration of α-glycylglycine have been calculated using the vibrational spectra of ten isotopic derivatives, selectively labeled with deuterium or nitrogen-15. It is shown that this force field permits the determination of the frequencies of glycylglycine-hydrochloride in the solid state, despite a structure very different from that of the zwitterion. The agreement is particularly satisfying for those modes of vibration most sensitive to molecular conformation. It is thus possible to use this type of calculation to determine the conformation of an oligopeptide.

Spodiosite analogs are a class of compounds related to the apatite family. The ir spectra (4000 to 200 cm−1) and the laser-Raman spectra were obtained for several analogs (Ca2(XO4)Cl in which X=P, As, or V) prepared by a reaction flux technique. Fundamental modes were identified, and empirical band assignments were made. Unquestionable band assignment of the v2 modes can be made using Raman spectra. Effects of solid-state interactions were noted in the spectra and interpreted by factor-group analysis using the factor group D2h. The spectra of chlorspodiosite (Ca2(PO4)Cl) were compared with the spectra of synthetically prepared chlorapatite.

The i.r. spectra of methyl cyanoacetate in both liquid and solid phases and of methyl cyanoacetate-d3 in the liquid phase have been recorded in the region 4000–250 cm−1. The Raman spectra of both the compounds in the liquid phase have also been recorded. A tentative vibrational assignment has been made both for the light and the heavy ester. Evidence is presented for the existence of conformational isomers in the liquid phase.

The infrared and Raman spectra of several dialkyl disulfides were measured and their conformations were discussed in relation with the characteristic S–S and C–S stretching vibrations. The infrared spectra in the solid state and the temperature dependence of Raman spectra were measured for ethyl methyl disulfide and diethyl disulfide. For ethyl methyl disulfide, the gauche-gauche isomer was more stable than the trans-gauche isomer by about 0.9 kcal/mol while for diethyl disulfide the gauche-gauche-gauche isomer was more stable than the trans-gauche-gauche isomer by about 0.6 kcal/mol in the liquid state. Only the gauche-gauche form for ethyl methyl disulfide and only the gauche-gauche-gauche form for diethyl disulfide were observed in the solid state.

The vibrational spectra of dichloroethylmethylsilane and 2,2-dichlorobutane have been measured. The vibrational assignments of these molecules have been made in relation to the rotational isomerism. The normal vibration calculations based on the modified Urey-Bradley force field have been carried out and have confirmed for both molecules that, in the liquid state, the trans and gauche isomers coexist, while the trans isomer alone persists in the crystalline state.

R-P(Se)F2- (R = CH3, C2H5, C3H11, C6H5, N(CH3)2, N(C2H5)2, NHSi(CH3)3) and R-P(Se)FCl-compounds (R = CH3, C2H5) can be prepared by reaction of R-P(Se)Cl2-derivatives with antimony(III)fluoride under reduced pressure. In some cases the oxidation of fluorophophines with elemental selenium is successful. The isolated compounds are colourless volatile liquids which are sensitive to air and moisture. The chemical properties are described. 1H-, 19F-, 31P-NMR-, IR- and Raman-spectroscopic data are given. Main stretching frequencies are discussed by comparison with similar oxygen- and sulphur-compounds.

Ro-vibrational spectra of HNCS and DNCS have been obtained in the spectral range 300–4000 cm−1 with a practical resolution limit of 0.06 cm−1 in the region 350–1200 cm−1 and 0.15 cm−1 in the region 1200–4000 cm−1. The observed fine structure permitted definitive assignments for some of the PQK, QQK, and RQK branches in both molecules, and yielded sets of rotational constants in substantial agreement with those obtained from recent microwave and far-infrared studies. Precise estimates of the band origins have been obtained and there is evidence of second-order Coriolis coupling between the three bending modes in each molecule. The isolation of the out-of-plane bending modes has lead to a re-assignment of ν3, ν4, ν5, and ν6 for each molecule. The band origins, uncorrected for Coriolis interaction, are for HNCS and DNCS, respectively. v 1 :3538.6 ±0.3, 2644.5±0.5 cm −1 ;v 2 :1989.0 ±0.3, 1944.3±0.5 cm −1 ;v 3 :857.0 ±0.6, 851.0±0.1 cm −1 ;v 4 :615.0 ±0.5, 549.1±0.2 cm −1 ;v 5 :469.2 ±0.1, 365.8 ±0.2 cm −1 ;v 6 :539.2 ±0.5, 481.0±0.1 cm −1

Vibrational spectra of the two Lewis complexes, phosphine borane, PH3BH3, and trifluoro-phosphine borane, PF3BH3, have been investigated for several isotopic species preserving C3v symmetry. New assignments are proposed and substantiated by normal coordinate analyses formulated in the compliance constant basis.

Vibrational spectra of π-C3H5Fe(CO)2NO and π-C3D5Fe(CO)2NO have been studied in the liquid and solid states. The spectra have been interpreted on the basis of a C3 molecular symmetry. A reassignment of some bands is proposed for the allylic fragment based on vH/vD isotopic shifts. Examination of spectra of deuteriated derivatives has also allowed a reasonable assignment of all modes involving the FeCO and FeNO groups.

Infrared and Raman spectra of D 4 -ortho, meta and para fluorochloro and fluorobromo benzenes are presented and assignments are given. Some of the bands of H 4 - p -fluorochloro benzene assigned earlier as fundamentals are shown to be due to impurities and alternate assignments are given. The observed frequencies of the H 4 and D 4 molecules are combined in a normal coordinate analysis to obtain a 33-parameter modified valence force field, for the in-plane vibrations, with an average difference of ±0.8% between observed and calculated frequencies. The normal coordinate analysis shows that many of the previous assignments of the ring modes ν 1 , ν 6 , and ν 12 for disubstituted benzenes are not very reliablie. Revised assignments with good correlation with the corresponding benzene modes are given.

The vibrational spectra of compounds Ln2WO6 and Ln2MoO6 (Ln = lanthanide, including Y and Bi) are reported. Neglecting details it is possible to assign the internal vibrations of the molybdate and tungstate group. The results are in agreement with the structural data known up till now and suggest further that tungsten in the unknown Y2WO6 structure is in six-coordination, that Bi2MoO6 shows still another modification than koechlinite and that vibrational spectroscopy may yield additional structural information for compounds like those under consideration.

Analysis of the complete vibrational spectra of a series of X 3 MCo(CO) 4 molecules (M = Si, Ge, Sn; X = H, D, F, Cl, Br, I) has permitted valence force field calculations. The bonding forces can be interpreted in terms of a bonding scheme in which the metal-ligand backbonding proves to be the most important contributor. The metal-metal stretching force constant decreases in the series F > Cl > Br ≈ H, D > I for a particular metal. For a specific ligand X, the sequence is Ge > Si > Sn.