Early wheels were simple wooden disks with a hole for the axle. In the early Roman empire, most horse-carts used a design featuring two chords across the wheel. The spoked wheel was invented much more recently, and allowed the construction of lighter and swifter vehicles.
Chromium(III) sulfide. Chromium(III) Sulfide is the inorganic compound with the formula Cr2S3. It is a brown-black solid. Chromium sulfides are usually nonstoichiometric compounds, with formulas ranging from CrS to Cr0.67S (corresponding to Cr2S3). Preparation.
Chemical Formulas Write the chemical formula for the following compounds: 1. Hydrogen sulfide gas_____ H2S(g) 2. Aluminum oxide _____ Al2O3 3. Potassium cyanide _____KCN 4. Sulfur tetrachloride _____ SCl4 5. Hydrobromic acid _____ HBr 6. Calcium oxide _____ CaO 7. Ammonium chloride _____ NH4Cl 8.