Sodium selenate, formation

Highly toxic groups will be found. They may be used to step up old nematocides or bring new ones to the fore. However, soil nematocides are contact killers and as such will be supplanted by chemotherapy. Plants will be fed materials toxic to the nematode. Such chemicals (stomach poisons) are already here, as indicated by sodium selenate. Plant parasitic nematodes can bathe in it, but unless it is absorbed by the plant and thus fed to the nematode, no injury is done. The mode of action of parathion is still uncertain. Plant parasitic nematodes placed in a saturated aqueous solution certainly survive for long periods, yet it has been found effective in the control of certain nematodes in living plants 16y 0), The next step is the introduction into the plant of nutriments to replace those taken from the plant by the nematode. The final step is the introduction into the plant of neutralizers of nemic enzymes. This may have already been done in the case of parathion, for it is said to inhibit cholinesterase formation in other animals. Chemotherapy will then have its day, but when that day is done physics may be expected to take over liie burdens of the control of plant diseases. We can expect the use of ultrasonics and radioactive fertilizers. 

SEL/SAZ4] Selivanova, N. M., Sazykina, T. A., Heat of formation of sodium selenate decahydrate, Russ. J. Inorg. Chem., 7, (1962), 273-275. From a citation in this Bibliography... 

Bone marrow cells of male mice gavaged with sodium selenate or sodium selenite showed a significant increase in chromosome breaks and spindle disturbances compared with untreated controls (Biswas et al. 1997, 1999a). The number of chromosomal aberrations increased with dose and was slightly greater with sodium selenite than with sodium selenate. A significant increase in micronucleus formation was observed in bone marrow cells of male mice intraperitoneally injected with selenous acid and in female mice intramuscularly injected with sodium selenite, but not in male mice intraperitoneally injected with sodium selenate (Itoh and Shimada 1996 Rusov et al. 1996). 

EXPLOSION and FIRE CONCERNS combustible solid NFPA rating (NA) reacts to form explosive products with metal amides contact with acids may cause formation of poisonous hydrogen selenide gas incompatible or reacts violently with barium carbide, bromine pen-tafluoride, chromic oxide, fluorine, lithium carbide, lithium silicon, metals, nickel, sodium, nitric acid, nitrogen trichloride, oxygen, potassium, potassium bromate, rubidium carbide, zinc, silver bromate, uranium, strontium carbide, and thorium carbide toxic gases and vapors may be released in a fire involving selenium, sodium selenite, sodium selenate, and selenium dioxide use water for firefighting purposes. 

Thomsen also measured the enthalpy of reaction between one mole of selen-ious acid and one mole of sodium hydroxide in solution. His data are used in Table A-2 to estimate the standard enthalpy of formation of NaHSe03(cr). 

The complex formation between Sc and SeOj" was studied by measurement of the distribution of Sc between the aqueous phase and a cation exchanger at selenate concentrations in the range 0 to 0.167 M. Sodium perchlorate was added to keep the ionic strength at / = 0.5 M. The radioactive nuclide Sc was used to follow the distribution ratio at a total scandium concentration of 2 x 10 M. Measurements were carried out at 298.15, 308.15, and 318.15 K and the pH was adjusted to 4.0 to 4.5. No disturbance from the hydrolysis of Sc occurs at this pH according to the paper although this would be expected from the data in [76BAE/MES]. 

SOB/SEL] Sobol, L. G., Selivanova, N. M., Heat of formation of sodium hydrogen selenate NaHSe04., Izv. Vyssh. Uchebn. Zaved, Khim. Khim. Tekhnol., 16, (1973), 1493-1495, in Russian. Cited on pages 422, 526, 540. 

IsomoTphous selenates and sulfates. Many sulfates and sele-nates are isomorphous and very similar in appearance. It might be of interest to prepare small samples of CuSe04 5H20 and Na2SeO4T0H2O and compare them with the corresponding sulfates. The formation of mixed crystals by sodium sulfate and selenate could be investigated by using the analytical method for selenium described by Dennis and Koller. ... 

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