Each player receives ten tiles which represent metals and nonmetals found in binary ionic compounds as well as the more common polyatomic ions. (The detailed instructions list the polyatomic ions that are accepted by the app.) There are also six red tiles which can be used as buffer tiles, as shown in the video Using a Red Tile. The first player must use the black square located in the center of the board. Once a formula is played, that player will receive new tiles to replace the ones used, as long as there are tiles left.
The app contains three transition metals - copper (Cu), iron (Fe), and gold (Au). The copper tile can be used as either copper (I) or copper (II). The iron tile can be used as iron (II) or iron (III). The gold tile can be used as gold (I) or gold (III). The charge doesn't have to be the same when used in two separate formulas, which makes these tiles more versatile. In this video, a player uses a gold tile as gold(I) going across and as gold(III) going down.
Red tiles have no point value, but they are useful as buffer tiles. They can be used to open up new areas of the playing board when the board becomes cluttered. This is helpful near the end of the game when it becomes increasing more difficult to find open areas. They can also be used to take advantage of the squares that double and triple a formula's point value, as shown in this video. However, the square on which the red tile is played does not affect the score for the formula played.