ヘキサクロロジシロキサンおよびトリフルオロトリクロロジシロキサンの振動スペクトルならびに構造-2-

The infrared spectra of Cl3SiOSiCl3 and F3SiOSiCl3 in gaseous state are measured and the Raman spectra of the molecules are reexamined using Ar+ laser. The new results support the author\u27s original contention concerning the structures of these molecules, but require some minor adjustments in the earlier assignments.1-a) The vibrational spectrum of Cl3SiOSiCl3 has been measured, and it has been reported that the symmetry was C2v (bent). However the present observations seem to show that the vibrational bands obtained can be explained according to D3d selection rules(linear). Because the irreducible representation of C2v point group is 7A1 (R,p; IR) + 4A2(R) + 6B1(R; IR) + 4B2(R; IR), that is, all 21 fundamentals are allowed in the Raman effect (7 of them as polarized lines) and that 17 fundamentals are allowed in infrared absorption. On the other hand, that of D3d point group is 3A1g(R, p) + 3A2u(IR) + 3Eg(R) + 4Eu(IR). Accordingly the bands obtained are too simple to be ones of C2v model, and it is against C2v one that the obtained spectra are mutually exclusive in Raman and infrared. The vibrational spectrum of F3SiOSiCl3 should be assigned according to C3v (linear) or Cs(bent) model. The irreducible representation of C3v point group is 6A1 (R,P; IR) + 7E(R; IR) and that of Cs, 13A′(R,p;IR) + 8A〝(R;IR). The vibrational spectrum of F3SiOSiCl3 obtained seems to be assigned according to C3v selection rules, compared with those of structurally related molecules, Cl3SiOSiCl3, F3SiCl and FSiCl3. However the final decision must await the results of the further studies, because it is very important whether Si-O-Si chain is linear or not. The Raman spectra are recorded on JEOL JRS-S1B spectrophotometer using argon ion laser and the infrared spectra are measured with Shimadzu IR-450 spectrometer, whose gas cell had a path of 10 cm and KRS-5 windows

Some Questions on High School Chemistry

Some questions on high school chemistry were given to the author by high school chemistry teachers and university students, as follows; 1) Is the Avogadro\u27s number changed by changing the basis for an atomic weight? 2) Is the mass of reaction product changed, compared with the mass of reacting substance, according to the Einstein\u27s equation, even in chemical reactions? 3)An electrolysis of AgCl reaches the following equilibrium; AgCI(s) ⇄ Ag+ + CI- ∴K (equilibrium constant) =〔Ag+〕〔CI-〕/〔AgCI(S)〕What is the value of K and what is the concentration of pure solid AgCI represented by the 〔AgCI(s)〕?4) water dissociates electolytically in the following way:H2O⇄ H++OH-∴K (equilibrium constant)=[H+] [OH-]/[H2O] What is the value of K and what does the concentration of pure water represented by the [H2O] mean? 5) The reaction, 1/2 Cu +FeCI3→1/2 CuCI2 + FeCI2 occurs. On the basis of the ionization tendency, this reaction should not occur, because the ionization tendency of Fe is larger than that of Cu. Why does the reaction occur? 6) In the classification of subgroups of long type periodic Table, which is correct, (i) or (ii)? (i) Ia, IIa, IIIa, ..... , VIIa, VIII, Ib, IIb, IIIb, ..... , VIIb, 0 (ii) Ia, IIa, IIIb, ..... , VIIb, VIII, Ib, IIb, IIIa, ..... , VIIa, 0 7) Is it correct that Zn, Cd, and Hg are not considered as transition elements? 8) La and Ac are not the internal transition elements. Nevertheless, why are the series of internal transition elements called lanthanides or actinides which were derived from La or Ac

対称Si-Cl伸縮振動の振動数におけるヘキサクロロジシランの異常性および振動の帰属

The symmetric Si-Cl stretching of hexachlorodisilane, 352 cm-1 is found to be anomously low when a comparison with those of some compounds containing SiCl3 groups is made. This anomaly seems due to irltensive coupling of symmetric SiCl3 deformation with symmetric Si-Cl stretching and/or Si-Si stretching mode. On the basis of the above consideration, the vibrational assignments of hexachlorodisilane are tentatively done

エタン,ジメチル・エ-テル,ジメチル・サルファイド,ジメチル・セレナイドおよびジメチル・テルライドの回転-振動スペクトルならびに構造

There are two possible configurations for H3C-X-CH3 (X=O,S,Se,Te), linear or bent C-X-C, the latter having C2v symmetry. For a linear model the methyl groups may be staggered, D3d or eclipsed, D3h. A bent model, C2v allows 21 fundamentals, all of which are active in Raman and 17 of which are active in infrared. This means that a C2v symmetry should have 17 coincidences between Raman and infrared spectra among 21 fundamental frequencies. The obtained spectra indicate the general simplicity of the spectra and the lack of coincidence between Raman and infrared frequencies. In addition, the rotation-vibrational band contours consist of a family of Q branches having an intensity alternation for degenerate infrared ones, which indicates the existence of C3 symmetry about the C-X-C axis of rotation. Consequently, the linear models are strongly supported for H3CXCH3 type molecules and, of the linear configurations, the eclipsed D3h form is eliminated, because a D3h symmetry should indicate the coincidence between Raman and infrared frequencies in E′species. Above all, it seems to the authors sufficient evidence to justify a linear skeleton for H3CXCH3 that an intensity alternation in Q branch sequence of perpendicular band(Eu) is observed. However the final decision must await the results of the further studies, because structure of H3CXCH3 type molecule has been determined from electron diffraction and microwave spectroscopy to be approximately C2v symmetry. The Raman spectra are recorded on JEOL JRS-S1B spectrophotometer using Ar+ laser and the infrared spectra are measured with Shimadzu IR-450 spectrometer, whose gas cell had a path of 10 cm and KRS-5 windows

メタノールの回転-振動スペクトルおよび構造

The authors obtain the infrared rotation-vibrational spectrum of gaseous methanol and the Raman spectrum of liquid one. Actually the infrared as well as the Raman spectrum of methanol has been analyzed on the basis of CS symmetry. However, the present observations show that the vibrational bands of methanol obtained can be explained according to C3v selection rule, that is, it is in agreement with theoretical expectations for C3v model that four parallel type bands are polarized in Raman and have P, Q, and R branches in infrared, whose P-R separations are observed to be 40 cm-1 and estimated to be 43 cm-1 on the basis of the parameters for C3v model. In addition, the obtained spectra of methanol resemble very closely those of acetonitrile, whose symmetry is C3

The vibrational spectra and structures of hexachlorodisilazane and hexamethyldisilazane

The spectroscopic and structural investigations of haxachlorodisilazane and hexamethyldisilazane are reported. According to their spectra, the structure of those molecules seem to be D3d. Generally, a rigid D3d is indistinguishable from an internal rotating D′3h according to vibrational spectra. However, in this case, the molecules appear to be D′3h structure with free rotation of SiX3(X=Cl, Me) groups

New Proposal of Subgroup Classification in Long Form of the Periodic Table

In the paper "Confusion in the Periodic Table of the Elements" published in Journal of Chemical Education in the U. S., the American Chemical Society (ACS) has asked for an alternative suggestion to the traditional designations to avoid the present confusion caused by the use of some designations of A and B Groups III-VIII in a manner opposite to each in the subgroups of long, or expanded form of the Periodic Table. It is common knowledge that the same confusion prevails in Japan also. The author proposes to designate typical elements as Subgroup A, transition elements as Subghoup B and inner transition elements as Subgroup C. The private views that the elements Zn, Cd and Hg ought to be classified as the transition element and how to designate the inner transition element series will be stated hereafter