The composition dependence of some physical properties of Cabal and Babal glasses is discussed for the purpose of elucidating the role of aluminum ion in the structure of alkaline earth aluminoborate glasses. To interpret the experimental results on the basis of the glass structure, three rules are assumed about interlinking relation among AlO₄ tetrahedron, BO₄ tetrahedron and BO₃ triangle as follows.
(Rule 1) In the structure of alkaline earth aluminoborate glass, when each content of MO and B₂O₃ in the glass exceeds a definite value, preferential interlinking between AlO₄ and BO₄ groups in made into the formation of a tetrahedron couple comprising those two kinds of tetrahedral group.
(Rule 2) The interlinked tetrahedron couple is impossible to exist only by itself, but is forced to link to BO₃ triangles at its six corners in any case. Hence, the formation of AlB₃O₇ group as a structural unit of aluminoborate is resulted (cf. Fig. 10).
(Rule 3) When there are any excess amounts of B₂O₃ and MO beyond the composition corresponding to MAlB₃O₇, an another tetrahedron couple comprising two BO₄ groups forms newly in borate structure part. Further the couple is forced to link to six BO₃ triangles in accordance with the mode of rule 1 and 2, and as the result B₄O₇ group forms.
Following conclusions are obtained by applying these rules as a fundamental principle for interpreting the anomalous changes in the properties of the glass series investigated.
(1) Substituting MO for B₂O₃ in the MO-Al₂O₃-B₂O₃ system brings the glass system to encounter with a drastic change in some fundamental properties at a composition within the range of 28 to 36 mol% MO.
(2) The composition dependence of some properties of the aluminoborate glasses is explained reasonaly by applying the above-mentioned three rules and by assuming that some part of aluminum ions in the higher Al₂O₃ containing glass takes the form of triclustered AlO₄ group involving one tripod oxygen ion per unit.
(3) Not only the formation of non-bridging oxygen ions but the dissociation of AlB₃O₇ group brings about a drastic change in physical properties such as transformation or deformation temperature, microhardness, ionic refraction of oxygen and true oxygen volume of glass. The composition at which the anomaly appears is determined by the one cause going ahead of other between the above two.
(4) About the expansivity anomaly found in the lower MO composition range (15-20mol%), however, no reasonable understanding may be obtained from the above principle. Therefore, a new discussion should be done from the other viewpoint.

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The coordination number of Al ions in many calcium aluminates was examined by using electron probe X-ray microanalysis and fluorescent X-ray spectrography. A single crystal of α-Al₂O₃ embedded in CaO powder was heated at 1395°C for 74hrs. The compounds C₃A, C₁₂A₇, CA, CA₂ and CA₆ were formed in thin layers between CaO and α-Al₂O₃.
The shift of the AlK_α peak about this sample was measured by an electron probe X-ray microanalyser. The shift of the AlK_α peak about calcium aluminates prepared from powdered oxides was also measured by an X-ray spectrometer.
The results indicate that the aluminum ions in C₃A, C₁₂A₇, CA and CA₂ are in fourfold coordination, whereas those in CA₆ are in both fourfold and sixfold coordination.
When the Al contents of materials containing calcium aluminates are determined using an ADP crystal of an electron probe X-ray microanalyser, the ues of metallic Al or α-Al₂O₃ as the standard for positioning the goniometer causes differences of more than 10 wt% in Al₂O₃ concentration, because of the large shift of the peak.

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It is well established that partial solid solution occurs in the pseudo-binary system C₃A-Na₂O within the system CaO-Al₂O₃-Na₂O at temperatures below the liquidus. The X-ray powder diffraction patterns of several compositions in the above solid solution series showed that two orthorhombic forms with the different unit cells are present in the series, and that the transition between these two forms takes place at about 4.8% Na₂O. For the preparations containing 5.9 and 3.7% Na₂O which are the extremes of the solid solution series at 1, 350°C, the orthorhombic unit cells are a=15.314, b=15.394, c=15.137 Å and a=10.872, b=10.845, c=15.112 Å respectively.
The unit cell for the high-Na₂O form with more than 4.8% Na₂O is of the type proposed by Fletcher, Midgley and Moore (1965). The low-Na₂O form was shown to be isomorphous with the prismatic phase in the interstitial material of Portland cement clinker.

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Barium titanate is generally made from barium carbonate and titanium dioxide.
When equimolar BaCO₃-TiO₂ mixtures are heated, the over-all net reaction for BaTiO₃ formation is BaCO₃+TiO₂=BaTiO₃+CO₂-98cal/g.
But all of the compounds present simultaneously after the initial reaction, and in air barium ortho-titanate (Ba₂TiO₄) forms in much larger amounts, either with increasing temperature or time. In 1 atm of CO₂, however, Ba₂TiO₄ is suppressed up to a temperature of about 1100°C.
In order to produce BaTiO₃ from BaCO₃ and TiO₂ in a lower heating temperature, the suppression of byproducts and the rationalization of a heating process is studied.
As regards the preparation of the sample, barium carbonate, titanium dioxide (anatase type) and petroleum cokes are respectively pulverized in a ball mill to a determinate particle size (about 325 mesh), which are mixed thoroughly by using a V-type rotary mixer. The mixed solid is press-shaped into a cylinder (bulk density=about 2.5g/cm³), from which a sphere is formed by cutting (Dp=3 or 5cm). The mixing ratio of BaCO₃ and TiO₂ is equi mole. The mixing ratio of petroleum cokes is 4 to 15 per cent by weight. The shaped samples are heated and the following results are obtained.
1) A heating temperature for the formation of BaTiO₃ can fall to a lower temperature (below 1000°C), and the complete time of reaction of a particle can become fairly short.
2) Ba₂TiOc₄ is suppressed up to a temperature of about 1100°C.
3) The mixing ratio of petroleum cokes of a particle may be 3 to 5 per cent by weight in the region of present experiments.

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Chemical analysis, X-ray analysis, determination of specific gravity, various thermal tests and HCl-solubility test, etc. were conducted on 18 samples of wollastonite from Kiura, Oita Prefecture.
The following results were obtained;
(1) The main mineral component of the samples studied is wollastonite or parawollastonite, often containing quartz and calcite.
(2) The 18 samples of wollastonite examined have the following physical propertis: apparent specific gravity 2.8-3.0, bulk specific gravity 2.7-3.0, apparent porosity 0.4-3.3%, moisture content 0.2-1.1%. The chemical composition is SiO₂ 43.60-59.09%, Al₂O₃0.31-2.05, Fe₂O₃ 0.25-1.07%, CaO 37.88-49.83%, MgO 0.39-2.24%, Ig. loss 0.54-9.29%.
(3) The thermal expansion up to 1000°C is 0.7-0.8%, and the thermal expansion curve shows nearly a straight line and there is not any unusual expansion. (as shown in Fig. 10)
(4) The transition of wollastonite (or parawollastonite) to pseudowollastonite begins at about 1200°C and almost ends at 1350°C. It seems that the transition temperature is determined by the kind and quantity of the impurities in the samples.
(5) It is possible to obtain higher quality wollastonite by acid treatment, but it must be treated with concentrated acid in order to separate calcite completely and in so doing the loss of wollastonite becomes considerably great.

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