Antimony hydride, SbHs

The grid metallics should be stored and recovered separately from the battery paste so that metals from the alloys in the battery grids do not contaminate the relatively pure lead paste, which is ideal for producing soft lead. Alloys used to manufacture VRLA batteries do not contain either antimony or arsenic, and this means that the potential hazard of stibine (antimony hydride, SbHs) and arsine (arsenic hydride, AsHs) formation during the storage of the metallics is removed. Many automotive batteries with antimonial and arsenical alloys are still in use. 

Stibine, Antimony hydride. HjSb mol wt 124.78. H 2 42%.. Sb 97.57%.. SbH,. Conveniently prepd by dissolving zinc-antimony or magaesium -antimony alloy in dil HC1 Hurd, Chemistry of the Hydrides (Wiley. New York, 1952) p 132. Detailed directions (including prepn of the alloy from powdered Sb and Mg) Schenk in Handbook of Preparative Inorganic Chemistry voL 1, O. Brauer, Ed. (Academic Press, New York. 2nd ed.. 1963) pp 606-608. Review of preparative methods Jolly, Norman, Hydrides of Groups IV and V in Preparative Inorganic Reactions vnl. 4, W. L. Jolty, Ed. (Interscience, New York, 1968) pp 1 -58. 

SbHs SbH5, antimony pentahydride [SbH5], X5-stibane (parent hydride name), pentahydridoantimony ... 

The three hydrides of arsenic, antimony, and bismuth are arsine (AsHj), stibine (SbHs), and bismuthine (BiHs) all are thermally unstable and have high positive enthalpies of formation 166,145, and 278 kJ/mol, respectively. The three hydrides are colorless, poisonous gases that decompose on heating to give the elements. The decomposition temperatures for AsHs, SbHs, and BiHs are about 250, 30, and -45°C, respectively. 

The hydrides ASH3 and SbH3 resemble those of PH3 (Table 15.4), but they are less stable with respect to decomposition into their elements. The thermal instability of AsHa and SbHs was the basis for the Marsh test. This is a classic analytical technique used in forensic science in which arsenic- or antimony-containing materials were first converted to AsHs or SbHs, and the latter were then thermally decomposed (eq. 15.32). Treatment of the brown-black residue with aqueous NaOCl was used to distinguish between As (which reacted, eq. 15.33) and Sb (which did not react). 

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