Barium stannate

Other. Insoluble alkaline-earth metal and heavy metal stannates are prepared by the metathetic reaction of a soluble salt of the metal with a soluble alkah—metal stannate. They are used as additives to ceramic dielectric bodies (32). The use of bismuth stannate [12777-45-6] Bi2(Sn02)3 5H20, with barium titanate produces a ceramic capacitor body of uniform dielectric constant over a substantial temperature range (33). Ceramic and dielectric properties of individual stannates are given in Reference 34. Other typical commercially available stannates are barium stannate [12009-18-6] BaSnO calcium stannate [12013 6-6] CaSnO magnesium stannate [12032-29-0], MgSnO and strontium stannate [12143-34-9], SrSnO. ... 

The hematite with adsorbed Co-57 or Sb-119 along with the solution was subjected to emission Mossbauer measurement at 24 1°C with the experimental setup shown in Figure 2. The absorber, Fe-57-enriched potassium ferrocyanide (0.5 mg Fe-57/cm2) or barium stannate (0.9 mg Sn-119/cm2), was driven by a Hanger 700-series Mossbauer spectrometer connected to a Tracor-Northern TN-7200 multi-channel analyzer. The Mosssbauer gamma-rays of Co-57 and Sb-119 were detected respectively with a Kr(+3% carbon dioxide)-filled proportional counter and with a 2 mm-thick Nal(Tl) scintillation counter through 65 pm-thick Pd critical absorber for Sn K X-rays. The integral errors in the relative velocity were estimated to be of the order of 0.05 mm/s by repeated calibration measurements using standard absorbers. 

Let us now discuss some recent work by Sano and myself on completely characterizing barium stannate, a material first proposed by Plotnikova, Mitrofanov, and Shpinel (21), as a source for tin Mossbauer spectroscopy. It is easily prepared, is a stoichiometric compound and has all the properties one desires in a Mossbauer matrix. The recoil-free fraction at room temperature is about 0.55 with about a 10% error. The line width extrapolated to zero absorber thickness is about 6% larger than natural—i.e., the line width observed is ca. 0.318 mm./sec. at zero ab-... 

R. H. Herber Dr. Sano really has done most of the work on barium stannate in our laboratory. This material has one weakness when compared with the standard in cobalt-57 spectroscopy—i,e, it has no quadru-pole splitting. Otherwise, it is a stoichiometric compound which one can presumably prepare easily and reproducibly. I am not the person to propose it as a standard. Moreover, there are some other suitable candidates we haven t as yet studied, which should be considered. 

A. F. Peterson (M T Chemicals, Inc., Rahway, N. J.) Barium stannate is a commercial product M T Chemicals manufactures. 

Dr. Peterson OflF-hand I cannot answer, but the company probably manufactured it from a stannic hydrate, and I am sure that if there is suflBcient interest, they would certainly produce a pure barium stannate as a standard. 

FIGURE 9 Temperature dependence of the n Sn Mbssbauer isomer shift in (CH, )2 Sn(acac),. Error-bars represent one standard deviation. The IS scale is with respect to a room temperature barium stannate absorber spectrum. 

A source matrix which shows no line broadening due to unresolved quadrupole splitting and which gives a large recoil-free fraction at room temperature is barium stannate, BaSnOa [18], and this is rapidly becoming the most popular source for tin MQssbauer spectroscopy. The /-fraction is 0-6 at 293 K and 0-46 at 690 K. The source linewidth is close to the natural width [19]. A method of preparation has been detailed [19], and the material can also be used with high eflSciency in a resonant counter [18]. 

Barium stannate trihydrate BaSn03 3Hj0 12009-18-6 368.081 wh cry powder si HjO s acid... 

Barium Stannate. BaSn03 it is sometimes added to barium titanate bodies to decrease the Curie temperature. An electroceramic containing approx. 90 mol% BaTi03 10 mol%, BaSn03 has a very high dielectric constant (8000-12000 at 20°C). Barium Sulphate. BaSO m.p. 1580°C sp. gr. 4.45. 

Barium stannate (BaSnOs) powders ofhigh purity have been synthesized by the use of a polyacrylamide gel method (Licheron et al., 1997). Figure 7-1 presents a flow sheet of the synthetic protocol leading to gel formation. 

Figure 7-1. Flow sheet of barium stannate gel formation from salts and polymer (Licheron, 1997).

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