(I) The System Ferrous Oxide-Phosphoric Acid-Water and some of its Oxidation Products. The existence of the monohydrogen ferrous phosphate Fe(HPO<sub>4</sub>),H20 (or 2FeO, P<sub>2</sub>O<sub>5</sub>, 3H<sub> 2</sub>O) has "been confirmed. This com-pound was described by Debray but subsequently Erlenmeyer cast doubt on Debray's results. The compound has been obtained in two forms, viz. "amorphous" and crystalline, the latter showing a decidedly lower solubility. In addition a dihydrate Fe(HPO<sub>4</sub>), 2H<sub>2</sub>O (or 2FeO, P<sub>2</sub>O<sub>5</sub>, 5H<sub>2</sub>O) has been shown to exist. The dihydrogen phosphate Fe(H<sub>2</sub>PO<sub>4</sub>)<sub> 2</sub>, 2H<sub>2</sub>O (or FeO, P<sub>2</sub>O<sub>5</sub>, 4H<sub>2</sub>O) described by Erlenmeyer has been confirmed. It is thought that the ferrous phosphates are not complex. By the oxidatiod of phase mixtures poor in acid a red-brown ferric phosphate betaFe<sub> 2</sub>O<sub>3</sub>, P<sub>2</sub>O<sub>5</sub>, 4H<sub>2</sub>O is deposited, which is only stable when ferrous iron is present in the liquid phase (at 70°). By completing the oxidation the substance changes both in crystalline form and colour (to pink) to a solid having the same empirical composition. It is thought2that the latter is a complex ferri-phosphate, whilst the former is a true ferric phosphate. (II) An Aeparatus for the Viscosimetric Determination of Transition Points. By means of an apparatus combining the functions of a viscometer and a stirrer the transition points Na<sub>2</sub>SO<sub>4</sub>, 10 ↔ OH<sub>2</sub>O, NiSO<sub>4</sub>, 7 ↔ 6H<sub>2</sub>O, and Na<sub>2</sub>HPO<sub>4</sub>, 12 ↔ 7H<sub>2</sub>O have been determined. (III) The System Ferric Oxide-Arsenic Acid-Water at Low Concentrations of Arsenic Acid. The following solid phases have been found to exist between 2·6 and 23·13% of As<sub>2</sub>O<sub>5</sub> in the liquid phase at 25°: Fe<sub>2</sub>O<sub>3</sub>, As<sub>2</sub>O<sub> 5</sub>, xH<sub>2</sub>O (where x is probably near 6); Fe<sub> 2</sub>O<sub>3</sub>, 2As<sub>2</sub>O<sub>5</sub>, 8H<sub>2</sub>O. The latter compound has not been described before as far as is known. Its existence provides evidence that the ferric arsenates, like the phosphates, are complex. No basic salts were obtained. The system was characterised by an extreme sluggishness in approaching equilibrium.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:703590 |
| Date | January 1927 |
| Creators | Hartshorne, Norman H. |
| Publisher | Royal Holloway, University of London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://repository.royalholloway.ac.uk/items/0791c9c4-a3b8-4a99-b7ab-b3259cc7b72d/1/ |
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