Contents 1. Introduction 3877 2. Bonding 3877 3. Doubly Bonded Compounds 3882 3.1. Compounds of Formula REdER (E ) Group 13 Element) 3882 3.2. Compounds of Formula REdE′R 2 (E Group 13, E′ ) Group 14 Element) and Related Species 3884 3.3. Dianions of Formula [R 2 EdER 2 ] 2-(E ) Group 13 Element) 3884 3.4. Monoanions of Formula [R 2 EdE′R′ 2 ] -(E ) Group 13, E′ ) Group 14 Element) 3885 3.5. Compounds of Formula R 2 E-E ¨′R 2 (E ) Group 13, E′ ) Group 15 Element) and Related Species 3886 3.6. Compounds of Formula R 2 E-E′R and [R 2 E-E′] -(E ) Group 13, E′ ) Group 16 Element) 3888 3.7. Compounds of Formula R 2 EdER 2 , [L:E ¨dE ¨:L] and [RE ¨dE ¨R] 2-(E ) Group 14 Element) 3888 3.8. Compounds of Formula R 2 EdE ¨′R (E ) Group 14, E′ ) Group 15 Element) 3896 3.9. Compounds of Formula [R 2 EdE ¨′R 2 ] + (E ) Group 14, E′ ) Group 15 Element) 3900 3.10. Compounds of Formula R 2 EdE ¨′ (E ) Group 14, E′ ) Group 16 Element) 3901 3.11. Compounds of Formula RE ¨)E ¨R, (E or E′ ) N, P, As, Sb, or Bi) 3902 3.12. Compounds of Formula RE ¨dE′ (E ) Group 15, E′ ) Group 16 Element) 3908 4. Triply Bonded Compounds 3908 4.1. Group 13 Derivatives 3908 4.2. Group 14 Derivatives 3909 4.3. Compounds with Potential Triple Bonding between Group 14 and Group 15 Elements 3912 4.4. Compounds with Potential Triple Bonding between Group 14 and Group 16 Elements 3913 4.5. Compounds with Triple Bonding between Group 15 Elements 3913 5. Conclusions 3914 6. List of Abbreviations 3914 7. Acknowledgments 3915 8. References 3915