H2S and H2SO

The report by Van Wazer in this volume (Chapter 2) of calculations for the molecules H2S, H2SO, and H2SO2 prompts us to present our results for comparison. We considered first this series as part of a study of bonding in sulfoxides and sulfones, using an early version of the GIVNAP program. We have repeated them with ARCANA using the atom positions chosen by Van Wazer. The results are displayed in Table VII. 

The d-orbital exponent chosen to be 0.45, 0.435, and 0.42 for H2S, H2SO, and H2SO2 respectively. The symbols (95/52/3) and (951/52/3) mean that 9 s-type, 5 p-type and respectively either none or 1 d-type orbital exponents are used to describe the sulfur atom 5 s-type and 2 p-type to describe each oxygen, if present and 3 5-type to describe each hydrogen atom. 

Tables IV through VI give the orbital symmetries, their energies, and the electronic populations, as well as the major bonding contribution to each of the delocalized orbitals for the molecules H2S, H2SO, and H2SO2 respectively. The numbers in italics in these tables (numbers which are labeled A) show the change, induced by allowing d character, in the particular value associated with the given orbital. For example, the value of A of 0.155 presented in Table V for the S-O overlap population of orbital 3a" of the H2SO molecule indicates that there is an increase of 0.155 electrons in the S-O bond when d character is allowed—i.e., the calculated value of the S-O overlap population of orbital 3a" of H2SO for...

In Table III, the results for calculations with and without d orbitals on the sulfur are intercompared. Allowing d orbitals to the sulfur caused a decrease of 0.02% in the total energy for H2S, 0.04% for H2SO, and 0.06% for H2SO2. As expected, the value of the dipole moment of H2S... 

FIGURE 6. The MOs of H2S (left) combining with the two sp hybrids and two p orbitals of oxygen to give the MOs of H2SO (shown in Figure 7). 

Acids are named based on their anions. If the name of the anion ends in -ide, the acid name starts with hydro- and ends in -ic, as in hydrosulfuric acid (H2S). If the acid is an oxyacid, the ending -ic is used for the species with more oxygens and -ous for the species with fewer oxygens, as in sulfuric acid (11 S04) and sulfurous add (H2SO,). 

H H plane are shown for the H2SO2 molecule only, since the H2S and H2SO molecules exhibit similar plots. The main part of the total electron density in this plane is centered around the sulfur nucleus. 

Figure 10.1 Cyclic voltammograms of flame-cleaned (H2 -t- Ar atmosphere) (A) Pt(111), (B) Pt(lOO) and (C) Pt(l 10), all in 0.5 M H2SO, at 50 mVs . Reproduced with permission from Ref [9], Societe Chemique de France.

Place 100 ml. of the SnClj-HPOj filtrate in a large test tulie. Introduce into the filtrate a gas filter tube with a sintered glass filter, about 20 mm. in diameter connect the test tube to a HjS tank and pass HjS slowly through the solution for 15 minutes. The test tube should be fitted with a rubber stopper throi h which are passed the HjS tube and an exhaust tube, which in turn is passed into a laige flask containing lime water to absorb the H2S the entire apparatus is placed under a hood. To 50 ml. of the HjS-saturated solution add 0.5 g. of thiourea, shake until dissolved, and filter. Bubble CO2 through the filtrate for 5 minutes. Pipet 4 ml. aliquots of this solution into each of three matched colorimeter tubes. Add 1 ml. of 2% 2,4-dinitrophenylhydrazine in 9 AT H2SO< to two of the tubes and keep one tube as a blank. Place the three tubes in a water bath at 37 C. for 6 hours. From here on the analysis is the same as that described above for the Norit filtrate. The result obtained here is the DKA value. 

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