Space group spectra

It is well known that vanadium can replace phosphorus or arsenic in the apatite lattice. Most of the orthovanadates which crystallize in this form have been investigated by IR and Raman spectroscopic techniques 62—64). The results of these studies are summarized in Table 4. The space group of all of these compounds is certainly C ft with the VO4 ion lying on a C site. Therefore, one should always find a nine band spectrum. Phosphorus apatites behave similarly, as seen in Ref. (65). 

The only compound of this formula type of which a structure analysis has been carried out, seems to be (NHdaMnFs (274). Dingle (83), who investigated the visible spectrum of this compound, reports (NH4)2MnFs to crystallize in the orthorhombic space group Pnma. 

Both compounds crystallize with the cadmium diiodide structure (space group P3ml) as previously reported on polycrystalline samples.3 For platinum disulfide, ao = 3.542(1) A and c0 = 5.043(1) A, and for platinum ditelluride, a0 = 4.023(1) A and c0 = 5.220(3) A. Direct chemical analysis for the component elements was not carried out. Instead, precision density and unit-cell determinations were performed to characterize the samples. The densities of both compounds as determined by a hydrostatic technique with heptadecafluorodeca-hydro-l-(trifluoromethyl)naphthalene as the density fluid4 indicated that they are slightly deficient in platinum. For platinum disulfide, = 7.86 g/cm3 and Pmeas = 7.7(1) gm/cm3, and for platinum ditelluride, p = 10.2 gm/cm3 and Pmeas = 9.8(1) gm/cm3. In a typical experiment an emission spectrum of the platinum disulfide showed that phosphorus was present in less than 5 ppm. A mass spectroscopic examination of the platinum ditelluride revealed a small doping by sulfur (less than 0.4%) and traces of chlorine and phosphorus (less than 100 ppm). 

Cr CNNi(tetren) 6](C104)9 is a red-purple solid, soluble in water-acetonitrile mixtures where the undissociated heptanuclear entity can be identified by electrospray ionization mass spectrometry. IR spectroscopy shows the presence of a unique /cn band at 2146 cm of the bridging cyano ligand and an intense band of the perchlorate anion at cr = 1090 cm The IR spectrum of the C-enriched compound prepared from K3[Cr( CN)6] displays a /cn band at 2103 cm The compound crystallizes in a trigonal system, space group R3, with parameters a = b = 15.274 A and c = 41.549 A. The magnetic properties indicate a ferro-... 

The compound [space group 7 3, a = 32.719 (1), c = 73.567 (2) A] is obtained by a ligand exchange (30 CHaCOO by 30 H2PO2 ) reaction. The IR spectrum is practically identical to that of compound A except for the appearance of H2PO2 bands [1118 (m), 1075 (w), 1033 (m) cm ] instead of CHsCOO bands. Also the Raman and electronic absorption spectra are almost identical to those of compound A. 

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