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 bond a protic acid and the borane end is hydridic. The resulting B−HH−N attractions stabilize the molecule as a solid. In contrast, the related substance ethane, HCCH, is a gas with a boiling point 285 °C lower. Because two hydrogen centers are involved, the interaction is termed a dihydrogen bond. Formation of a dihydrogen bond is assumed to precede formation of H from the reaction of a hydride and a protic acid. A very short dihydrogen bond is observed in NaBH·2HO with H−H contacts of 1.79, 1.86, and 1.94 Å. Protonation of transition metal hydride complexes is generally thought to occur