Arsenic phase diagrams

The nickel-arsenic phase diagram [61YUN], [87S1N/NAS] is moderately complex, with the compounds Ni5As2(cr), Nii Asg(cr) (nickel-deficient Ni3As2(cr)), NiAs(cr) and NiAs2(cr) (with a p to a conversion near 870 K). 

Tin becomes hard when alloyed with arsenic and there is a tendency for the alloys to crystallize. A full tin-arsenic phase diagram has been recorded. ... 

Okamoto, H. (1992) Arsenic-Indium. In Phase Diagram of Indium Alloys and Their Engineering Applications, eds. White, C.E.T. and Okamoto, H. (ASM International, Materials Park, OH), p. 26. 

L. -L. Sun, F. Zhou, and Z.-X. Zhao, Superconductivity and phase diagram in iron-based arsenic-oxides RcFcAsOi r (Re = rare-earth metal) without fluorine doping, Europhys. Lett. 83 17002 (2008). 

PIC. 24-4. Phase diagram for the binary system arsenic-lead. 

The Binary System Lead-Tin. The phase diagram for the lead-tin system of alloys is shown as Figure 24-5. This system rather closely resembles the system arsenic-lead, except for the fact that there is an appreciable solubility of tin in crystalline lead and a small solubility... 

Crytal chemitry. Solid solutions of lead phosphate compounds with structures like that of palmierite ((K,Na)2Pb(S04)2) exhibit transition sequences that are well modeled by Landau-Ginzburg excess free energy expressions. Systems that have been especially heavily studied include Pb3(Pi (As (04)2 (Toledano et al. 1975, Torres 1975, Bismayer and Salje 1981, Bismayer et al. 1982, 1986 Salje and Wruck 1983) and (Pbi jcA c)3(P04)2, where A = Sr or Ba (Bismayer et al. 1994, 1995). The phase diagram for the phosphate-arsenate join is not completely mapped, but Bismayer and collaborators have identified a series of transitions for the P-rich and the As-rich fields. The structure consists of two sheets of isolated (P,As)04-tetrahedra with vertices pointing towards each other and a sheet of Pb atoms in the plane of the apical oxygen atoms. Layers of Pb atoms lie between these tetrahedral sheets (Fig. 18) (Viswanathan and Miehe 1978). 

Figure V-12 The phase diagram selenium-arsenic as optimised in [97DEG/PEL]. Reprinted from [97DEG/PEL] with permission from ASM International.

SIN/NAS] Singleton, M., Nash, P., The As-Ni (arsenic-nickel) system. Bull. Alloy Phase Diagrams, 8, (1997), 419-422. Cited on pages 210, 212. 

The phase diagram for the lead-tin system of alloys is shown as Figure 17-6. This system rather closely resembles the system arsenic-lead, except that there is an appreciable solubility of tin in crystalline lead and a small solubility of lead in crystalline tin. The phase designated a is a solid solution of tin in lead, the solubility being 19.5 mass percent at the eutectic temperature and dropping to 2% at room temperature. The phase /8 is a solid solution of lead in tin, the solubility being about 2% at the eutectic temperature and extremely small at room temperature. The eutectic composition is about 62 mass percent tin, 38 mass percent lead. 

Fig. 125. Main features of the phase diagrams of arsenic with rare earths and actinides.

A different application of chemical equilibrium leads to an explanation of how the incorporation of defects and dopants depends on the growth conditions (Winer and Street 1989). Section S.l describes the unexpected rf power and gas concentration dependence of the dopant distribution coefficient, particularly for arsenic doping. A schematic diagram of the growth process is shown in Fig. 6.19, in which three-fold and four-fold silicon and dopants are deposited from the gas phase. The deposition reactions proposed for arsenic doping are... 

Figure 3 Eh-pH stability diagram for arsenic in the presence of sulfur at 25 °C, 1 bar total pressure. The stability field for water is shown by the dashed lines. The gray area represents a solid phase.

Figure 1 Simplified pe-pH diagram for the As-S-HjO system at 25°C constructed based on the following assumptions SO4 = lO M, HjAsOj = 10" M, and AS2S3 = amorphous orpiment (see Table 1). The diagram does not consider the importance of As(V)-Fe(III)-hydroxide solid phases likely to he predominant under oxidized conditions, nor does it consider more reduced forms of arsenic potentially found in solid phases, such as realgar (AsS) and arsenopyrite (FeAsS), or as gaseous forms such as arsine (AsHj).

The InAs-InjTe, InAs-Te, and InAs-As Te, sections in the ternary indium-arsenic-tellurium system were studied by physicochemical analytical methods. Solid solutions based on indium arsenide were found in the system, and die possible existence of the phases InAsTe, InAsTe, is postulated, these melting with decomposition at 680 and 390 C, respectively. The results were used to construct a diagram for the liquidus surface of the indium-arsenic -tellurium system. It is suggested diat teUurium may exhibit amphoteric properties. 

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