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.
The formula for phosphorous (III) oxide is determined by the electron shells of the phosphorus and oxygen. Oxygen is in group 6, so it will gain 2 electrons to have a charge o â¦ f -2 per atom. The Roman numerals (III) with the phosphorous tells us that the phosphorous atoms are in a +3 state, and Roman numerals are used to tell us the ionization state of atoms that have multiple possible states.