Being a tetrabasic acid it can form four classes of salts; for example, the four solium salts Na 4 P 2 0 7, Na3HP207, Na 2 H 2 P 2 0 7, NaH 3 P 2 0 7 are known.
When dissolved in water it yields some NaOH and H202; on crystallizing a cold 'solution Na202.8H20 separates as large tabular hexagonal crystals, which on drying over sulphuric acid give Na 2 0 2.2H 2 0; the former is also obtained by precipitating a mixture of caustic soda and hydrogen peroxide solutions with alcohol.
At that temperature crystals of the anhydrous Na 2 SO 4 appear, and a new fixed equilibrium exists between the four phases - hydrate, anhydrous salt, solution and vapour.
Bird, Annals of Natal,1495-1845(2 vols., Maritzburg, 1888); C. de Mello, Os Inglezes na Africa austral (Lisbon, 1890); E.
And A ultimo corrida de touros reaes em Salvaterra by Rebello da Silva, and Urn Anno na Corte by the statesman, Andrade Corvo, the first and the last superior books.
William Lilly's account of the meeting of Napier and Briggs at Merchiston is quoted in the article NA Pier.
The sodium salt, Na 4 P 2 0 6.10H 2 O, forms monoclinic prisms and in solution is strongly alkaline; the acid salt, Na3HP206.9H20, forms monoclinic tablets.
It is held that an excess of the latter is undesirable in wine, but unless the quantity appreciably exceeds two grams per litre, na reasonable objection can be raised.
Sodium bichromate, Na 2 Cr 2 0 7.2H 2 0, may be obtained by the addition of the requisite quantity of chromium trioxide to a solution of sodium chromate.
Above the sea, the more prominent parts of which have received special names - Driesh, Mayar, Tom Buidhe, Tolmount, Cairn na Glasha.