Four new crystal structures, P(O)(OC6H5)(2)(NHNHC6H5) (I), P(S)(OCH3)(2)(NHCH(CH3)(2)) (II), P(S)(OCH3)(2)(NH-cyclo-C5H9) (III) and [2-Cl-C6H4CH2NH3](2)[(CH3S)P(O)(O)-O-P(O)(O)(SCH3)] (IV) were studied. The P-O-C angles were analyzed, considering phosphoryl compound (I) and thiophosphoryl compounds (II) and (III) and their analogous structures deposited in the Cambridge Structural Database (CSD), including 282 P(O)(O)(2)(N) structures (706 P-O-C angles) and 186 P(S)(O)(2)(N) structures (518 P-O-C angles) with at least one P-O-C angle. The maximum populations of P-O-C angles are within 120A degrees-122A degrees in both P(O)(O)(2)(N) and P(S)(O)(2)(N) families of structures, confirming the hybridization state close to sp (2) for the oxygen atom of P-O-C. A survey on the CSD resulted in 11 P(O)(O)(2)(S-C) structures (11 P-S-C angles), and the structure (IV) belonging to this family of compounds is the first diffraction study of a salt with a (S)P(O)(O)-O-P(O)(O)(S) skeleton in the anion component. For the P-S-C angles, the maximum population was found in the range of 100A degrees-104A degrees showing the angles within those related to unhybridized pure p orbitals (p (3)) and hybridized sp (3) for the sulfur atom of P-S-C. The analysis of 187 P(O)-O-P(O) structures (with no restriction on the other two atoms attached to phosphorus) including 538 P-O-P angles yielded the maximum population of P-O-P angles within 132A degrees-134A degrees, showing the more pronounced "s" character of the orbital (with respect to the sp (2) and toward sp) for the oxygen atom at the P-O-P moiety.