Apparent partition coefficients of lead and strontium between barium sulfate and aqueous solution were determined under various conditions changing temperatures, chloride concentrations and degrees of supersaturation of the solution with respect to BaSO₄.
It was found that the apparent partition coefficients of lead and strontium are largely controlled by the degree of supersaturation of aqueous solution with BaSO₄ as well as temperature and chloride concentration.
The coefficients for lead ranged from 0.034 to 0.22 when initial solutions contain 0.004 mole/1 to 0.00025 mole/1 of barium plus lead ions in BaSO₄–PbSO₄ binary series. In the BaSO₄–PbSO₄–SrSO₄ ternary series, the coefficients for lead were from about 0.1 to 0.6 when the total cations in the initial solution changed from 0.0024 mole/1 to 0.0006 mole/1 and 0.05 to 0.15 with 0.05 mole/1 chloride ion. The values for strontium are from 4.1×10⁻³ to 1.5×10⁻² with the same change of the total cation concentration in the solution.
These experimental results were consistent with the partition of lead and strontium between Tamagawa Hot Spring water and hokutolite when the coefficients are related with barium and sulfate concentration in the solution.

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Laihunite, an apparent nonstoichiometric olivine-type mineral, shows a 3C type superstructure. This mineral has a basic cell of a=4.805(2)Å, b=10.189(9)Å, c=5.801(3)Å and α=91.0(2)° and the space group P2₁⁄b(a=unique axis) for the average structure. The basic structure has been studied by the single crystal X-ray method, starting from the model presented by Fu et al. (1979) with 889 reflections collected by four-circle diffractometry. The final weighted R and R factors are 0. 067 and 0. 075, respectively, after the three-dimensional least squares refinements. The mean T–O, M(1)–O, M(2)–O and V–O distances are 1.637(3), 2.185(1), 2.040(2) and 2.205(2)Å, respectively. The site occupancies and the bond distances of M(1), M(2) and V sites indicate the following distribution of iron atoms; V (Fe²⁺ 0.20), M(1) (Fe²⁺ and Mg²⁺, ∼1.00) and M(2) (Fe²⁺∼0.20, Fe³⁺∼0.80). The chemical formula of laihunite in this study is, therefore, approximately     _0.40Fe_0.80²⁺Fe_0.80³⁺SiO₄, indicating nonstoichiometry of laihunite.

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The crystal structure of an Agoura clinoptilolite has been studied at 350°C. The monoclinic cell at room temperature is distorted to triclinic, giving cell dimensions of a=17.698(15)Å, b=17.511(8)Å, c=7.392(5)Å, α=90.21(5)°, β=116.76(5)°, γ=90.19(5)Å. The probable space group is C-1. Structure analysis revealed that the potassium atom located at the M(3) site at room temperature is still preserved at around the same site while those located at the cation sites other than M(3) are missing. The result supports the prediction made by Koyama and Takéuchi (1977) regarding the thermal stability of clinoptilolite.

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