Monobasic phosphate

Many important soil components are not present as simple cations or anions but as oxyanions that include both important metals and nonmetals. The most common and important metal oxyanion is molybdate (Mo042 ). The most common and important nonmetal oxyanions are those of carbon (e.g., bicarbonate [HC03 ] and carbonate [C032-]), nitrogen (e.g., nitrate [N03 ] and nitrite [NQ2 ]), and phosphorus (e.g., monobasic phosphate [H2P04 ], dibasic... 

The monobasic phosphate as dihydrate is a white crystalline powdery material hygroscopic decomposes on heating dissolves in water soluble in acids with reaction insoluble in alcohol. 

Prepare 0.25 M pH buffer solutions ranging from pH 0.5 to 9. (Note that phosphate buffer is only good for pH = 4.5-9 due to the dissociation constant.) Before coming to the lab, review how to make a pH buffer solution in a freshman chemistry textbook and calculate the relative amounts of KH2PO4 (monobasic phosphate) and K HPO O (dibasic phosphate) needed to make these phosphate buffer solutions. 

Fig. 11 A caking diagram showing the flocculation of a bismuth subnitrate suspension by means of the flocculating agent, potassium monobasic phosphate.

Monobasic phosphate hemihydrate, Cj7HjjN07p.k4Hj0. Prepd from equimolar amounts of morphine and phosphoric acid Homeyer et at, (J-S. pat. 2,665,227 (1954 to Mallinck-rodt). Stout monoclinic crystals from water + organic sol -vent. One gram dissolves in 5 ml water. pH of a 1% aq sotn at 25 = 4.6. 

As thus obtained, it appears in the shape of a colourless and transparent glass, which slowly dissolves in water. It is hence called glacial phosphoric acid. Its solution causes in solutions of silver a white granular precipitate of monobasic phosphate of silver it also coa lates albumen. But if long kept, or if very rapidly boiled, this solution passes into one of tribasic phosphoric acid, and no longer precipitates silver or coagulates albumen. Here 2 eqs. of water enter into the composition of the acid P O HO + 2H0 = P,0 3H0. 

With bases, this acid forms one series of salts, the monobasic phosphates, the general formula of which is P, 0, MO, or P, Oj, M. In these, the hydrogen of the acid is replaced by its equivalent of metal. The precipitate caused by the acid in solutions of silver is one of these salts, P, O5, Ag 0. 

If the third or acid phosphate of soda be ignited, it loses 2 eqs. of basic water, and monobasic phosphate is left, which, if dissolved in water, gives with silver a granular white precipitate of monobasic phosphate, the supernatant liquid remaining neutral. 

According to the above views, therefore, the general formula for a monobasic phosphate is P, 0,., M, or P, O, MO. Monobasic phosphate of soda, PjO, Na, or PjO, NaO, is obtained by heating the acid tribasie phosphate of soda to redness, when it loses 2 eq. of water, and monobasic phosphate is left. It is soluble, but not crystallisable, and gives, with chloride of barium, a bulky precipitate, which is P,03,Ba, orP,0, BaO jandwith nitrate of silver, a flaky white precipitate, which is P, 0, Ag, orP,0,AgO. 

As to the influence of the phosphates on the protease of yeast, the same effect is observed here as was observed by Fernbach in the case of pancreatin. Dibasic phosphate is injurious, an equimolal mixture of monobasic phosphate KH2PO4 (0.76 per cent) and of dibasic phospdrate K2HPO4 (0.979 per cent) is without effect, while monopotassium phosphate is distinctly favorable. The following table, expressing these results, indicates that the favorable action of the acid phosphate is exerted just as well at as at 50°. Furthermore, its efficacy incveases with the quantity used ... 

Diprotonated sapphyrins were also found to bind monobasic phosphate anions in solution and in the solid state.The same proved true for monoprotonated sapphyrins, at least in polar protic solvents. This led Sessler and Iverson to consider the possibility that sapphyrins might interact with Consistent with... 

Betamethasone acetate Sodium dibasic phosphate Sodium monobasic phosphate NaOH or HCI Water for injection... 

Figure 6. Single crystal X-ray structure of the 1 1 chelated complex formed between monobasic phosphoric acid and sapphyrin 3c. The phosphate is held ca. 0.83 A above the sapphyrin plane by 5 hydrogen bonds. For each diprotonated 3c, there is also a non-ligated monobasic phosphate.

Figure 7. Single crystal X-ray structure of the 2 1 bis-phenylphosphate salt of sapphyrin 3b. The two monobasic phosphate anions are held 1.22 and 1.60 A above and below the sapphyrin plane and are chelated by 3 and 2 hydrogen bonds, respectively.

H3PO4 H2PO4- Dihydrogen phosphate Monobasic phosphate... 

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