Phase Equilibria and Vapor Pressures of Pure Phosphorus and of the Indium/Phosphorus System and Their Implications Regarding Crystal Growth of InP
Phase Equilibria and Vapor Pressures of Pure Phosphorus and of the Indium/Phosphorus System and Their Implications Regarding Crystal Growth of InP
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DOI：
10.1149/1.2401931
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发表时间：
1974-06
影响因子：
3.9
通讯作者：
K. Bachmann;E. Buehler
中科院分区：
文献类型：
--
作者：
K. Bachmann;E. Buehler
测量了几种商业级红磷和专门制备的晶体样品的蒸气压随温度的变化。对于结晶红 P，我们获得升华热，AHs= 31.9• 1 kcal/mole。商业级产品的蒸气压高于 450~，由方程式 In p=--(10.8• 0.4)• IO~/T+(16.5 _ 0.6) 描述。红磷的升华平衡可用于控制磷压力，p> 10 atm，如果使用至少 5N 纯度的商业磷，则重现性为 10%。对 800~~ T~ 1400~ 和 3arm~ p~ 35arm 范围内磷蒸气 pVT 关系的测量表明，与理想气体行为的偏差高达 10%。当范德华方程与 Marckwald 和 Helmholz 的临界数据以及 0.375 的临界系数一起用于计算余体积和相互作用参数时，可以在描述磷蒸气行为方面获得出色的精度。考虑到平衡常数 K 的压力依赖性，对于反应 P4:2P2，得出了在 1000 和 1100 时的逸度常数的近似值。通过同时蒸气压和 DTA 测量，建立了富铟和富磷组合物的化学计量 InP 附近液相线处的 pTx 关系。 InP的化学计量熔点为1335 ___ I~，相应的磷平衡压力为27.5• 1 atm。假设液体的理想行为而计算出的 Tx 液相线数据与我们的实验数据非常吻合。对液相线压力数据的解释可得出 298~ 处的标准焓和熵值
The vapor pressure as a function of temperature of several commercial grades of red phosphorus and a specially prepared crystalline sample has been measured. For crystalline red P we obtain a heat of sublimation, AHs= 31.9• 1 kcal/mole. The commercial grades yield vapor pressures, which above 450~ are described by the equation In p=--(10.8• 0.4)• IO~/T+(16.5 _ 0.6). The sublimation equilibrium of red P can be utilized for controlling phosphorus pressures, p> 10 atm, with a reproducibility of 10% if commercial P of at least 5N purity is used. Measurements of the pVT relation of phosphorus vapor in the regimes 800~~ T~ 1400~ and 3 arm~ p~ 35 arm reveal deviations up to 10% from ideal gas behavior. Excellent accuracy in describing the behavior of phosphorus vapor is obtained when van der Waals equation is used in conjunction with the critical data of Marckwald and Helmholz and a critical coefficient of 0.375 for calculation of both the covolume and the interaction parameter. Consideration of the pressure dependence of the equilibrium constant K, for the reaction P4: 2P2 yielded approximate values for the fugacity constant at 1000 and ll00~ The pTx relation at the liquidus in the vicinity of stoichiometric InP for indiumrich and phosphorus-rich compositions were established by simultaneous vapor pressure and DTA measurements. The melting point of stoichiometric InP is 1335 ___ I~ and the corresponding equilibrium phosphorus pressure is 27.5• 1 atm. Tx liquidus data calculated with the assumption of ideal behavior of the liquid are in good agreement with our experimental data. Interpretation of the liquidus pressure data yields values of the standard enthalpies and entropies at 298~