Preparation and Physical Properties

Heteropoly compounds are prepared in several ways. Solids are obtained by either precipitation, recrystallization or drying depending on the structure and composition. Caution must be used during preparation processes for hydrolytic decomposition of polyanions and nonhomogeneity of the metal cation to polyanion ratio in the precipitates. More elaborate preparation and characterization are necessary for the preparation of polyanions with mixed addenda atoms. 

Heteropoly compounds in the solid state consist of heteropolyanions, cations, (protons, and metal or onium ions) and water of crystallization and/or other molecules. This three-dimensional arrangement of polyanions, etc. may be called the secondary structures and the heteropolyanions are denoted the primary structures. It is important for the understanding of heteropoly compounds in the solid state to make a clear distinction between the primary and the secondary structure. 

If one looks at the IR spectra which reflect the primary structure and the XRD powder patterns which depend on the secondary structure of 12-molybdophosphoric acid (PM012) having different amounts of water, as well as its salts, the following important conclusion can be drawn In the solid state of a heteropoly compound, the primary structure is rather stable, but the secondary structure is very variable. 

Changes in heteropoly compounds upon a heat treatment have been extensively studied by the use of TC, DTA, XRD, etc. Acid forms are usually obtained with a large amount of the water of crystallization. Most of them are released below 370 K. Decomposition, which takes place at 620 — 870 K, is believed to be, e.g. 

H3PW12O40 is much more thermally stable and more resistant to reduction than H3PMoi2O40. 

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J.H. Grezlak, The Preparation and Physical Properties of Polyester-Poly(Methyl Methacrylates) Triblock Copolymers , TR for Jan 1— March 1, 1975, Contract N00014-67-A-0151-0011. Princeton Univ, Princeton (1975)... 

B. Alkoxy- and Aryloxy-derivatives.—The preparation and physical properties of a series of thermally stable monoalkoxy (or aryloxy) fiuoro-cyclophosphazenes have been reported ... 

Cationic ferrocene complexes with one, two, and four cationic [B(R)bpy] (bpy = 2,2,-bipyridine) acceptors such as 66 show absorption at Amax = 496-540 nm with the contribution of charge transfer between the ferrocene unit and the B(R)bpy substituent(s) (165). This is confirmed by the EPR spectrum of the monoreduced neutral species, which features a line shape indicating a considerable admixture of the ligand and metal orbitals. Preparation and physical properties of the related polymer, 67, have also been reported (166). 

Yamaguchi, H. (1994b). Preparation and physical properties of wood fixed with silicic acid compounds. Mokuzai Gakkaishi, 40(8), 838-845. 

The method of preparation and physical properties of the alkyl azides used in the study are also presented in Table 2.1. The alkyl bromide and sodium azide in aq MeOH is denoted as A and aq EtOH and sodium azide is denoted as B. 1,2-Diazidobenzene and 1,4-diazidobenzene were synthesized using the process shown in Fig. 2.10. 1-Azidonorborniane was synthesized according to a modified literature procedure shown in Fig. 2.11. 

Ota A, Yamochi H, Saito G (2002) Preparation and physical properties of conductive EDO-TTF complexes. Mol Cryst Liq Cryst 376 177-182... 

Because of the recent claims of room-temperature superconductivity in materials by several research groups, two additional criteria are further required to certify that a material is superconducting. These are long-term stability, and reproducibility in the preparation and physical property determination,... 

Pristera, Preparation and Physical Properties of Di- and Trinitrotoluene Isomers , PATR 2525... 

Table 4.2 Preparation and physical properties of oligo(a,a -thiophene—thioxophosphole)s...

Andon, R.J.L., Biddiscombe, D.P., Cox, J.D., Handley, R., Harrop, D., Herington, E.F.G., Martin, J.F (1960) Thermodynamic properties of organic oxygen compounds. Part 1. Preparation and physical properties of pure phenol, cresols, and xylenols. J. Chem. Soc. 5246-5254. 

A thorough review of the preparations and physical properties of the polynuclear cobalt complexes is given in Gmelins Handbuch der anor-ganischen Chemie (10). 

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