Chapter III: Typical Systems of One Component 21

A. _Water._ Equilibrium between liquid and vapour. Vaporization
curve, 21. Upper limit of vaporization curve, 23.
Sublimation curve of ice, 24. Equilibrium between ice and
water. Curve of fusion, 25. Equilibrium between ice, water,
and vapour. The triple point, 27. Bivariant systems of water,
29. Supercooled water. Metastable state, 30. Other systems
of the substance water, 32. B. _Sulphur_, 33. Polymorphism, 33.
Sulphur, 34. Triple point--Rhombic and monoclinic sulphur
and vapour. Transition point, 34. Condensed systems, 36.
Suspended transformation, 37. Transition curve--Rhombic
and monoclinic sulphur, 37. Triple point--Monoclinic sulphur,
liquid, and vapour. Melting point of monoclinic sulphur, 38.
Triple point--Rhombic and monoclinic sulphur and liquid, 38.
Triple point--Rhombic sulphur, liquid, and vapour. Metastable
triple point, 38. Fusion curve of rhombic sulphur, 39.
Bivariant systems, 39. C. _Tin_, 41. Transition point, 41.
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Enantiotropy and monotropy, 44. D. _Phosphorus_, 46. Enantiotropy
combined with monotropy, 51. E. _Liquid Crystals_, 51.
Phenomena observed, 51. Nature of liquid crystals, 52. Equilibrium
relations in the case of liquid crystals, 53.

CHAPTER IV

GENERAL SUMMARY 55

Triple point, 55. Theorems of van't Hoff and of Le Chatelier,
57. Changes at the triple point, 58. Triple point solid--solid--vapour,
62. Sublimation and vaporization curves,
63. Fusion curve--Transition curve, 66. Suspended transformation.
Metastable equilibria, 69. Velocity of transformation,
70. Law of successive reactions, 73.

CHAPTER V

SYSTEMS OF TWO COMPONENTS--PHENOMENA OF DISSOCIATION 76

Different systems of two components, 77. PHENOMENA OF
DISSOCIATION. Bivariant systems, 79. Univariant systems,
80. Ammonia compounds of metal chlorides, 82. Salts with
water of crystallization, 85. Efflorescence, 86. Indefiniteness
of the vapour pressure of a hydrate, 87. Suspended transformation,
89. Range of existence of hydrates, 90. Constancy
of vapour pressure and the formation of compounds, 90.
Measurement of the vapour pressure of hydrates, 91.

CHAPTER VI

SOLUTIONS 92

Definition, 92. SOLUTIONS OF GASES IN LIQUIDS, 93.
SOLUTIONS OF LIQUIDS IN LIQUIDS, 95. Partial or limited
miscibility, 96. Phenol and water, 97. Methylethylketone
and water, 100. Triethylamine and water, 101. General form
of concentration-temperature curve, 101. Pressure-concentration
diagram, 102. Complete miscibility, 104. Pressure-concentration
diagram, 104.

CHAPTER VII

SOLUTIONS OF SOLIDS IN LIQUIDS, ONLY ONE OF THE COMPONENTS BEING
VOLATILE 106

General, 106. The saturated solution, 108. Form of the
solubility curve, 108. A. ANHYDROUS SALT AND WATER.
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The solubility curve, 111. Suspended transformation and
supersaturation, 113. Solubility curve at higher temperatures,
114. (1) _Complete miscibility of the fused components._ Ice as
solid phase, 116. Cryohydrates, 117. Changes at the quadruple
point, 119. Freezing mixtures, 120. (2) _Partial miscibility of
the fused components._ Supersaturation, 124. Pressure-temperature
diagram, 126. Vapour pressure of solid--solution--vapour,
126. Other univariant systems, 127. Bivariant systems, 129.
Deliquescence, 130. Separation of salt on evaporation, 130.
General summary, 131.

CHAPTER VIII

SOLUTIONS OF SOLIDS IN LIQUIDS, ONLY ONE OF THE COMPONENTS BEING
VOLATILE 133

B. HYDRATED SALT AND WATER, (1) _The compounds
formed do not have a definite melting point._ Concentration-temperature
diagram, 133. Sodium sulphate and water, 134.
Suspended transformation, 137. Dehydration by means of
anhydrous sodium sulphate, 138. Pressure-temperature diagram,
138. (2) _The compounds formed have a definite melting point._
Solubility curve of calcium chloride hexahydrate, 145.
Pressure-temperature diagram, 149. The indifferent point, 150.
The hydrates of ferric chloride, 151. Suspended transformation,
155. Evaporation of solutions at constant temperature, 155.
Inevaporable solutions, 157. Illustration, 158.

CHAPTER IX

EQUILIBRIA BETWEEN TWO VOLATILE COMPONENTS 161

General, 161. Iodine and chlorine, 161. Concentration-temperature
diagram, 162. Pressure-temperature diagram, 165.
Bivariant systems, 167. Sulphur dioxide and water, 169.
Pressure-temperature diagram, 170. Bivariant systems, 173.

CHAPTER X

SOLID SOLUTIONS. MIXED CRYSTALS 175

General, 175. Solution of gases in solids, 176. Palladium
and hydrogen, 178. Solutions of solids in solids. Mixed
crystals, 180. Formation of mixed crystals of isomorphous
substances, 182. I. The two components can form an unbroken
series of mixed crystals. (_a_) _The freezing points of all mixtures
lie between the freezing points of the pure components._ Examples,
183. Melting-point curve, 183. (_b_) _The freezing-point curve passes
through a maximum._ Example, 186. (_c_) _The freezing-point
curve passes through a minimum._ Example, 188. Fractional
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crystallization of mixed crystals, 188. II. The two components
do not form a continuous series of mixed crystals. (_a_) _The
freezing-point curve exhibits a transition point_, 190. Example,
190. (_b_) _The freezing-point curve exhibits a eutectic point_, 191.
Examples, 192. Changes in mixed crystals with the temperature,
192.

CHAPTER XI

EQUILIBRIUM BETWEEN DYNAMIC ISOMERIDES 195

Temperature-concentration diagram, 196. Transformation
of the unstable into the stable form, 201. Examples, 203.
_Benzaldoximes_, 203. _Acetaldehyde and paraldehyde_, 204.

CHAPTER XII

SUMMARY.--APPLICATION OF THE PHASE RULE TO THE STUDY OF SYSTEMS OF
TWO COMPONENTS 207

Summary of the different systems of two components, 208.
(1) _Organic compounds_, 212. (2) _Optically active substances_,
213. Examples, 216. Transformations, 217. (3) _Alloys_, 220.
Iron--carbon alloys, 223. Determination of the composition of
compounds without analysis, 228. Formation of minerals, 232.

CHAPTER XIII

SYSTEMS OF THREE COMPONENTS 234

General, 234. Graphic representation, 235.

CHAPTER XIV

SOLUTIONS OF LIQUIDS IN LIQUIDS 240

1. _The three components form only one pair of partially
miscible liquids_, 240. Retrograde solubility, 245. The influence
of temperature, 247. 2. _The three components can form two
pairs of partially miscible liquids_, 249. 3. _The three components
form three pairs of partially miscible liquids_, 251.

CHAPTER XV

PRESENCE OF SOLID PHASES 253

A. The ternary eutectic point, 253. Formation of compounds,
255. B. Equilibria at higher temperatures. Formation
of double salts, 258. Transition point, 258. Vapour pressure.
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Quintuple point, 261. Solubility curves at the transition point,
264. Decomposition of the double salt by water, 267. Transition
interval, 270. Summary, 271.

CHAPTER XVI

ISOTHERMAL CURVES AND THE SPACE MODEL 272

Non-formation of double salts, 272. Formation of double
salt, 273. Transition interval, 277. Isothermal evaporation,
278. Crystallization of double salt from solutions containing
excess of one component, 280. Formation of mixed crystals,
281. Application to the characterization of racemates, 282.
_Representation in space._ Space model for carnallite, 284.
Summary and numerical data, 287. Ferric chloride--hydrogen
chloride--water, 290. Ternary systems, 291. The isothermal
curves, 294. Basic Salts, 296. Bi_{2}O_{3}--N_{2}O_{5}--H_{2}O, 298.
Basic mercury salts, 301. Indirect determination of the composition
of the solid phase, 302.

CHAPTER XVII

ABSENCE OF LIQUID PHASE 305

Iron, carbon monoxide, carbon dioxide, 305.

CHAPTER XVIII

SYSTEMS OF FOUR COMPONENTS 312

Reciprocal salt-pairs. Choice of components, 313. Transition
point, 314. Formation of double salts, 315. Transition
interval, 315. Graphic representation, 316. Example, 317.
Ammonia-soda process, 320. Preparation of barium nitrite, 327.
Barium carbonate and potassium sulphate, 328.

APPENDIX

EXPERIMENTAL DETERMINATION OF THE TRANSITION POINT 331

I. The dilatometric method, 331. II. Measurement of
the vapour pressure, 334. III. Solubility measurements, 335.
IV. Thermometric method, 337. V. Optical method, 338.
VI. Electrical methods, 338.

NAME INDEX 341

SUBJECT INDEX 345

* * * * *

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THE PHASE RULE