The volatilization of alkali ions in (K,Na)NbO3 (KNN) ceramics was inhibited by doping them with alkaline earth metal ions. In addition, the grain growth behavior changed significantly as the sintering duration (ts) increased. At 1,100 °C, the volatilization of alkali ions in KNN ceramics was more suppressed when doped with alkaline earth metal ions with smaller ionic size. A Ca2+-doped KNN specimen with the least alkali ion volatilization exhibited a microstructure in which grain growth was completely suppressed, even under long-term sintering for ts = 30 h. The grain growth in Sr2+-doped and Ba2+-doped KNN specimens was suppressed until ts = 10 h. However, at ts = 30 h, a heterogeneous microstructure with abnormal grains and small-sized matrix grains was observed. The size and number of abnormal grains and size distribution of matrix grains were considerably different between the Sr2+-doped and Ba2+-doped specimens. This microstructural diversity in KNN ceramics could be explained in terms of the crystal growth driving force required for two-dimensional nucleation, which was directly related to the number of vacancies in the material.

Competitive solvent extraction of the mixure of alkali metal and alkaline earth cation from water into organic solvent containing the crown ether carboxylic acid and anlogous crown ether phosphonic acid was investigated as follows. The lipophilic group is found to strongly influence to the selective extraction in the mixed systems from only alkali metal cation for sym-(n-decyldibenzo)-16-crown-5-oxyacetic acid _1 to mostly alkaline earth metal cation for sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid _3. Monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid _2. and monoethyl-sym- bis]4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid _4 showed good selectivity for Na+ over Mg2+, the second extracted ion. Structural variation in the crown ether phosphonic acid somewhat was influenced to the extraction selectivity in the mixed systems. when variation of the ionized group is influenced in the mixed systems, the selectivity of Na+ as the second extracted ion was much better crown ether carboxylic acid _1 than crown ether phosphonic acid _2, while the efficiency of Na+ extraction was better _2 (83% total loading) than _1 (32%).

A comparison of alkali metal cation and alkaline earth cation solvent extraction was made for three additional monoionizable crown ethers and one diionizable crown ether. sym-(n-Octyldibenzo)-16-crown-5-oxyacetic acid _1 exhibited high efficiency and selecvity in solvent extraction of alkali metal cations with respect to that observed with alkaline earth cations. Sizes of Na+ and Ca2+ appropriately match with the cavity size of monoethyl sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid _3. As the result, Na+ and Ca2+ are the best extracted. sym-(n-Octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid _4was found to be somewhat selective for Na+ over Li+ and other alkaline earth metal cations. In the complexation of alklaine earth cations by crown ether diphosphonic acid _4, Ca2+ and Sr2+ are the appropriate sizes, but lager Ba2+ may be due to favorable formation of a sandwich type complex between the crown ether cavity and the dianion of the deprotonated crown ether phoaphonic acid moiety.

Competitive solvent extraction of alkaline earth metal cations from water into organic solvent containing the carboxylic acid crown ether and analogous crown ether phosphonic acid monoethyl esters were investigated. sym-(n-Decyldibenzo)-16-crown-5xyacetic acid _1 and monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid _3 are structurally identical except for the ionizable groups. Both of them provide similar extraction behavior in terms of efficiency and selectivity, but monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid _3 showed higher alkaline earth metals loadings at acidic or neutral media. Monoethylsym-(n-octyldibenzo)-16-rown-5-oxymethylphosphonic acid _2 showed better selectivity and alkaline earth metals loading than did the analogous sym-(n-octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid _6.