Hydrides of arsenic, antimony and bismuth

OsSb2 CoAsS (i.e. pyrites C02AS2S2), NiSbS i.e. pyrites Ni(Sb-S), NiAsS (i.e. pyrites with random As and S on the S positions) 

Compounds of As, Sb and Bi with the metals in Group 13 (Al, Ga, In, Tl) comprise the important III-V semiconductors whose structures, properties, and extensive applications have already been discussed (pp. 255-8). Group 14 elements also readily form compounds of which the following serve as examples GeAs mp 737°C, GeAs2 mp 732°C, SnAs 

Minkwitz, a. Kornath, W. Sawodny and H. Hart-NER, Z artorg. allg. Chem. 620 753-6 (1994). 

Arsine, AsHs, is formed when many As-containing compounds are reduced with nascent hydrogen and its decomposition on a heated glass surface to form a metallic mirror formed the basis of Marsh s test for the element. The low-temperature reduction of AsCls with LiAlH4 in diethyl ether solution gives good yields of the gas as does the dilute acid hydrolysis of many arsenides of electropositive elements (Na, Mg, Zn, etc.). Similar reactions yield stibine, e.g.  

Both AsHy and SbH3 oxidize readily to the trioxide and water, and similar reactions occur with S and Se. ASH3 and SbH3 form arsenides and antimonides when heated with metals and this reaction also finds application in semiconductor technology e.g. highly purified SbHy is used as a gaseous n-type dopant for Si (p. 332). 

AuSbi CrSbi, FePi, FeAsi, FeSbi, RuPi, RuAsi, RuSbi, 

Thble 13.5 Comparison of the physical properties of AsHs, SbHs and BiHs with those of NH3 and PH3 

---

The hydrides of arsenic, antimony, and bismuth are unstable at elevated temperature. The Marsh test for arsenic depends on this instability when an arsenic mirror forms as arsine is passed through a heated tube ... 

Although no organoelement(V) hydrides of arsenic, antimony and bismuth are known, primary and secondary arsines (oxidation state III) may be obtained by the reduction of organoarsenic(V) compounds (equations 4 and 5) ... 

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. 

Pahlavanpour et al. [115] has described a method based on hydride generation and ICP-emission spectrometry for the determination of arsenic, antimony and bismuth in herbage. 

For organometalloid/organometallic compounds of arsenic, antimony and bismuth, all of the available directly determined enthalpies of formation are shown in Table 1, together with an indication of the experimental method used to obtain them and the appropriate literature references. Also included in Table 1 are the available enthalpy of formation data for the homoleptic hydrides, alkoxides and thiolates, respectively, because ... 

The optimal reaction conditions for the generation of the hydrides can be quite different for the various elements. The type of acid and its concentration in the sample solution often have a marked effect on sensitivity. Additional complications arise because many of the hydrideforming elements exist in two oxidation states which are not equally amenable to borohydride reduction. For example, potassium iodide is often used to pre-reduce AsV and SbV to the 3+ oxidation state for maximum sensitivity, but this can also cause reduction of Se IV to elemental selenium from which no hydride is formed. For this and other reasons Thompson et al. [132] found it necessary to develop a separate procedure for the determination of selenium in soils and sediments although arsenic, antimony and bismuth could be determined simultaneously [133]. A method for simultaneous determination of As III, Sb III and Se IV has been reported in which the problem of reduction of Se IV to Se O by potassium iodide was circumvented by adding the potassium iodide after the addition of sodium borohydride [134], Goulden et al. [123] have reported the simultaneous determination of arsenic, antimony, selenium, tin and bismuth, but it appears that in this case the generation of arsine and stibene occurs from the 5+ oxidation state. 

Thompson M., Pahlavanpour B., Walton S. J. and Kirkbright G. F. (1978) Simultaneous determination of trace concentrations of arsenic, antimony, bismuth, selenium and tellurium in aqueous solution by introduction of the gaseous hydrides into an ICP source for emission spectrometry, Analyst 103 568-579. 

Rigby, C Brindle, I.D. Determination of arsenic, antimony, bismuth, germanium, tin, selenium, and tellurium in 30% zinc sulphate solution by hydride generation inductively coupled plasma atomic emission spectrometry. J. Anal. Atomic Spectrom. 1999, 14, 253-258. 

Kuldveee a (1989) Extraction of geological materials with mineral acids for the determination of arsenic, antimony, bismuth and selenium by hydride generation atomic absorption spectrometry. Analyst 114 125-131. 

Schramel P and Xu L-Q (1991) Determination of arsenic, antimony, bismuth, selenium and tin in biological and environmental samples by continuous flow hydride generation ICP-AES without gas-liquid separator. Fresenius J Anal Chem 340 41-47. 

Nakashima et al. [719] detail a procedure for preliminary concentration of 16 elements from coastal waters and deep seawater, based on their reductive precipitation by sodium tetrahydroborate, prior to determination by graphite-furnace AAS. Results obtained on two reference materials are tabulated. This was a simple, rapid, and accurate technique for determination of a wide range of trace elements, including hydride-forming elements such as arsenic, selenium, tin, bismuth, antimony, and tellurium. The advantages of this procedure over other methods are indicated. 

---