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Title: Thermodynamic aspects of phosphorus compounds with particular reference to those containing the phosphorus-phosphorus bond
Author: Hameed, Abdul
Awarding Body: University of London
Current Institution: Royal Holloway, University of London
Date of Award: 1971
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The enthalpies of sublimation for triiodophosphine and diphosphorus tetraiodide have been determined via an effusion manometric technique as 15.2 +-0.9 (63.6 +- 3.8 KJ. mole-1) and 16.7 +- 0.5 kcal mole-1 (69.9 +- 2.1 KJ. mole-1) respectively. Incorporating these values in thermodynamic cycles along with anciliaiy literature data has resulted in a phosphorus-phosphorus bond energy in diphosphorus tetraiodide of 62 kcal mole-1 (259 KJ. mole 1). Mass spectrometrie measurement of the appearance potentials for tri-iodophoshine and diphosphorus tetraiodide gave 11.9 +- 0.15 and 12.8 +- 0.15 eV respectively. These data in combination with known ionization potentials give 73 +- 6 kcal mole -1(305 +- 25 KJ. mole -1) for the bond dissociation energy of the phosphorus-phosphorus bond in diphosphorus tetraiodide. Cracking patterns for some mononuclear adducts of the type X3PBX3 (X = Br or I) are reported. Reproducible synthetic routes for pentapherylcyclopentaphosphine and polymeric pherjylphosphine have been established. Thermocbeinical investigations have been made for the pentameric and polymeric phosphobenzenes by reaction-solution calorimetry and thermal analysis techniques. The standard heat of formation of tricyanophosphine (crystal) is derived via thermochemical measurements as 133.6 +- 0.4 kcal mole -1 (559.0 +- 1.7 KJ. mole -1) at 25?C. The enthalpy of complexing of diphosphorus tetraiodide-boron tribromide (1:2) adduct from diphosphorus tetraiodide and boron tribromide in carbon disulphide has been measured as -2.13 +- and the standard heat of formation of this molecular adduct is derived as -144.0 +- 1.6 kcal mole-1 (602.5 +- 6.7 KJ. mole-1). The enthalpy of hydrolysis of pentabroraophosphorane-boron tribromide is also recorded from which the standard heat of formation is found to be -142.0 +- 1.3 kcal mole 1 (-594.1).
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Physical Chemistry