Miscellaneous Multinary Oxides

In this catch-all Section, we mainly discuss the spinel structures with the generic formulas, AB2O4 and A2MO4. The unit cell of the spinel structure is a large cube, eight times (2x2x2) the size of a typical face centered cube.385 We also discuss the delafossite-type structure ABO 2 in which the A cation is in linear coordination 

Entry number Compound formula A cation(s) B cation (s) Comments References 

2 ATaCh Li, Na, K Excess alkali cation enhances catalytic activity. Co-catalysts not found to be essential although NiO was also used in addition in some studies. 442-446 

3 kiUiOib Sr Have layered perovskite structure. Samples with both Ta and Nb also studied. Strontium niobate compound is ferroelectric at room temperature. In contrast, the tantalum analog is paramagnetic. 426, 447-449 

5 ATa206 Mg, Ba, Sr Orthorhombic structure used with NiO co-catalyst to enhance photocatalyst activity. 442,451 

1 Ta2C 5 Both crystallized and mesoporous samples studied and in one case, (Ref. 441), NiO co-catalyst was used. 440,441 

---

Table 12. Miscellaneous multinary oxides for the photodecomposition of water.

---