41. Each trigonal prism shares two rectangular faces with the nearby prisms, forming infinite prism columns. 42. It is a regular square prism in three orientations, and a trigonal trapezohedron in four orientations. 43. In solid silver nitrate, the silver ions are three-coordinated in a trigonal planar arrangement. 44. In general, bond lengths in trigonal bipyramidal pentacoordinate species are longer than those in tetracoordinate analogues. 45. Besides tetrahedral, trigonal and octahedral holes, there were all-purpose balls with 24 holes. 46. "' Eucryptite "'is a lithium bearing aluminium trigonal -rhombohedral crystal system. 47. Sr + Ar 4 has two trigonal pyramids sharing a face and strontium at the common apex. 48. Pentacoordinated species are concluded to be more reactive because of their looser bonds as trigonal -bipyramidal structures. 49. The molecular geometry of the former is also trigonal bipyramidal, whereas that of the latter is linear. 50. Trigonal , tetragonal and hexagonal crystals have a single optic axis, parallel to the c crystal axis.
