41. Californium ( III ) polyborate is unusual in that californium is covalently bound to the borate . 42. The lone improvement for the half was in industrial minerals, such as borates and titanium dioxide. 43. Californium is the heaviest actinide to exhibit covalent properties, as is observed in the californium borate . 44. The most common compositions are based on lead borates ( leaded borate glass or borosilicate glass ). 45. The most common compositions are based on lead borates ( leaded borate glass or borosilicate glass ). 46. In the bulky borates and aluminates, the negative charge is symmetrically distributed over many electronegative atoms. 47. The "'borate minerals "'are minerals which contain a borate anion group. 48. The "'borate minerals "'are minerals which contain a borate anion group. 49. The capturing electrophile here is triisopropyl borate forming the boronic acid R B ( OH ) 2. 50. He was especially interested in hydrated borate minerals because of the crystal-chemical challenge they present.