Research and Development of Zincoborates: Crystal Growth, Structural Chemistry and Physicochemical Properties

Borates have been regarded as a rich source of functional materials due to their diverse structures and wide applications. Therein, zincobrates have aroused intensive interest owing to the effective structural and functional regulation effects of the strong-bonded zinc cations. In recent decades, numerous zincoborates with special crystal structures were obtained, such as Cs(3)Zn(6)B(9)O(21) and AZn(2)BO(3)X(2) (A = Na, K, Rb, NH(4); X = Cl, Br) series with KBe(2)BO(3)F(2)-type layered structures were designed via substituting Be with Zn atoms, providing a feasible strategy to design promising non-linear optical materials; KZnB(3)O(6) and Ba(4)Na(2)Zn(4)(B(3)O(6))(2)(B(12)O(24)) with novel edge-sharing [BO(4)](5−) tetrahedra were obtained under atmospheric pressure conditions, indicating that extreme conditions such as high pressure are not essential to obtain edge-sharing [BO(4)](5−)-containing borates; Ba(4)K(2)Zn(5)(B(3)O(6))(3)(B(9)O(19)) and Ba(2)KZn(3)(B(3)O(6))(B(6)O(13)) comprise two kinds of isolated polyborate anionic groups in one borate structure, which is rarely found in borates. Besides, many zincoborates emerged with particular physicochemical properties; for instance, Bi(2)ZnOB(2)O(6) and BaZnBO(3)F are promising non-linear optical (NLO) materials; Zn(4)B(6)O(13) and KZnB(3)O(6) possess anomalous thermal expansion properties, etc. In this review, the synthesis, crystal structure features and properties of representative zincoborates are summarized, which could provide significant guidance for the exploration and design of new zincoborates with special structures and excellent performance.