Yttrium carbonate

The reactions of the yttrium-carbon cluster ions were very ion dependent with dehydrogenation of water and loss of carbon groups common modes of reaction. 

Basic yttrium carbonate [Y(OH)COs] was deposited by CD and snbseqnently annealed in air at 600°C to Y2O3 [51 ]. Si wafers and self-assembled monolayers with sulphonate endgronps were used as substrates. An aqneons solntion of YNO3 and urea was heated at 80°C in sealed vials. The increase in pH, together with generation of carbonate from hydrolysis of urea (Sec. 3.2.4.1), resulted in formation of the basic carbonate. 

Roesky introduced bis(iminophosphorano)methanides to rare earth chemistry with a comprehensive study of trivalent rare earth bis(imino-phosphorano)methanide dichlorides by the synthesis of samarium (51), dysprosium (52), erbium (53), ytterbium (54), lutetium (55), and yttrium (56) derivatives.37 Complexes 51-56 were prepared from the corresponding anhydrous rare earth trichlorides and 7 in THF and 51 and 56 were further derivatised with two equivalents of potassium diphenylamide to produce 57 and 58, respectively.37 Additionally, treatment of 51, 53, and 56 with two equivalents of sodium cyclopentadienyl resulted in the formation of the bis(cyclopentadienly) derivatives 59-61.38 In 51-61 a metal-methanide bond was observed in the solid state, and for 56 this was shown to persist in solution by 13C NMR spectroscopy (8Ch 17.6 ppm, JYc = 3.6 2/py = 89.1 Hz). However, for 61 the NMR data suggested the yttrium-carbon bond was lost in solution. DFT calculations supported the presence of an yttrium-methanide contact in 56 with a calculated shared electron number (SEN) of 0.40 for the yttrium-carbon bond in a monomeric gas phase model of 56 for comparison, the yttrium-nitrogen bond SEN was calculated to be 0.41. 

Figure 1.23 The structure of Y(0H)C03 [21], (Reprinted from G.W. Beall, W.O. Milligan, and S. Mroczkowski, Yttrium carbonate hydroxide, Acta Crystallographica, B32, no. 11, 3143-3144, 1976, with permission from International Union of Crystallography.)...

The thermal decomposition of yttrium chloride hexahydrate in the presence of ammonium chloride has been studied. The dehydration of yttrium chloride monohydrate mixed with ammonium chloride was found to proceed at a lower temperature than the dehydration of the hexahydrate. The thermal decomposition of yttrium chloride hexahydrate in hydrogen chloride gave the penta-, tetra-, tri-, di-, and mono-hydrates of yttrium chloride and the anhydrous salts. In other media (air, vacuo) the dehydration of crystalline lower hydrates was accompanied by hydrolysis of the chloride and successive formation of Y(OH)Cl2, Y(OH)2Cl, and YOCl. The thermal stability of yttrium sulphate between 20 and 1500°C has been investigated. A thermographic and thermogravimetric study of the transformation of yttrium carbonate tetrahydrate by dehydration and thermal decomposition showed that residual water was only lost on decomposition. ... 

Recycling of yttrium is carried out in only small quantities, primarily from laser crystals and synthetic garnets (Hedrick 2002), but extraction may also be possible from used red phosphor or from South African fly ash and FeCr dusts (Deuber and Heim 1991). Basic yttrium carbonate is useful for the elimination of arsenite and arsenate ions from polluted water, including the recycling of yttrium (Wasay et al. 1996). 

N. J. Berlin said that the spontaneous evaporation of the soln. gives yellowish-brown dehquescent crystals. P. T. Cleve obtained potassium yttrium chromate, K2Cr04.Y2(Cr04)3.wH20, as a yellow, crystalline powder, by the action of potassium dichromate on yttrium carbonate. G. Kriiss and A. Loose, and W. Muthmann and C. R. Bohm also prepared erbium chromate, and ytterbium chromate. 

Pavlyuchenko MM, Kokhanovsky VV, Prodan EA (1970) Dehydration kinetics of crystalline hydrate of yttrium carbonate. In Pavlyuchenko MM, Prodan EA (eds) Heterogeneous chemical reactions. Nauka Tekhnika, Minsk (in Russian), pp 168-180... 

Waysay S. a., Haron M. D. J., UcmuMi A. and Tokunaga S. (1996) Removal of arsenite and arsenate ions from aqueous solution by basic yttrium carbonate. Water Res. 30, 1143-1148. 

The reaction mechanism probably encompasses formation of CO2 (Equation 4.2 and/or 4.7) and precipitation of yttrium carbonates. Formation of YAG phase was observed after calcination at 900°C for 1 h in material formed under UV irradiation of solution containing yttrium nitrate, aluminum chloride, and potassium formate calcination of the same material for 1 h at 1000 C yields pure powder YAG with well-developed crystals. Using electron-beam irradiation, YAG phase was still the major component of prepared material after calcination, but some amount of cubic yttrium oxide or rhombohedral a-Al203 was also detected after Ih calcination at 1000°C or 1300 C. 

Phase diagram of the yttrium-carbon system The phase diagram of the yttrium-carbon system was proposed by Carlson and Paulson (1968) and refined by Storms (1971), is shown in fig. 2. 

Here, the so-called heavy lanthanides include the elements from samarium to-lutetium, except for ytterbium and europium which behave like bivalent metals and have unique properties. For these heavy-lanthanide-carbon systems, no complete phase diagram was found, only some information about the formation and the crystal structure of the carbides is available. On the basis of these data the general characteristics of the phase diagrams of the heavy-rare-earth-carbon systems can be summarized. In this case the yttrium-carbon phase diagram may be regarded as the best prototype available for compounds of the heavy lanthanide systems with carbon. 

In addition to the hypocarbides and the dicarbides, there exist in the heavy-rare-earth-earbon systems the sesquicarbides and other carbides near 60%, as reported for the yttrium-carbon system, which has the same pseudocubic tetragonal cell as SC15C19 (Jedlicka et al. 1971). 

Summarizing the phase relationship in the heavy-lanthanide-carbon systems and the general characteristics with respect to formation of the carbides, it can be concluded that the phase diagram of the yttrium-carbon system is a good prototype of the heavy-lanthanide-carbon systems, which have not yet been studied in detail. In addition, on the basis of the yttrium-carbon phase diagram the unknown information about the R C phase diagrams could be deduced. 

The neophyl derivative of yttrium is formed by the same mechanism. The fact that 2 moles of tert-butyl benzene are evolved per yttrium in this reaction indicates the possible formation of a compound containing an yttrium-carbon triple bond (Guzman et al., 1979 Dolgoplosk et al., 1980) ... 

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