A colorless poisonous gas with a smell of rotten eggs, made by the action of acids on sulfides.
- ‘The gas component may be ethane, propane, butane, carbon dioxide, or hydrogen sulphide, but is most commonly methane.’
- ‘Several other gases are known to combine with water to form gas hydrates, including carbon dioxide and hydrogen sulphide, but by far the most common in marine sediments are methane hydrates.’
- ‘Seep output includes natural gas, carbon dioxide, nitrogen, hydrogen sulfide, other gases and oil.’
- ‘Increased concentrations of carbon dioxide and hydrogen sulfide were detected in the air, signs of fresh magma rising.’
- ‘The four usual agents of deterioration in the air apart from oxygen and water are sulphur dioxide, hydrogen sulphide, ozone and nitrogen dioxide.’
We take a look at several popular, though confusing, punctuation marks.