Sodium dihydrogen arsenate pyroarsenate salt NaHAsO. Sodium dihydrogen arsenate Sodium dihydrogen arsenate is the inorganic compound with the formula NaHAsO. Related salts are also called sodium arsenate, including NaHAsO (disodium hydrogen arsenate) and NaHAsO (sodium dihydrogen arsenate). Sodium dihydrogen arsenate is a colorless solid that is highly toxic. The salt is the conjugate base of arsenic acid: In the laboratory, it is prepared in this way, crystallizing from a hot saturated aqueous solution, where it is highly soluble when hot (75.3 g in 100 mL at 100 °C). It is obtained as the monohydrate. Upon heating, solid NaHAsOHO, loses water of crystallization and
Dihydrogen complex agostic interaction that is displaced by the H. In other cases, H will displace anionic ligands, sometimes even halides. Treatment of chlorobis(dppe)iron hydride with sodium tetrafluorborate under and atmostphere of hydrogen is one example: Many metal hydrides can be protonated to give dihydrogen complexes: In such cases the acid usually is derived from a weakly coordinating anion, e.g., Brookhart's acid. In 1984, Kubas et al. discovered that the addition of H to the purple-colored species M(CO)(PR) gave a yellow precipitate of mer-trans-M(CO)(PR)(H) (M = Mo or W; R = cyclohexyl, iso-propyl). This result rapidly led to the discovery of a