The bark contains calcium oxalate crystals. With the addition of oxalic acid, the yttrium oxalate precipitates. Common counterions include chloride, bromide, sulfate, phosphate, nitrate, acetate, oxalate, citrate, and tartrate. The oxide, hydroxide, fluoride, carbonate, phosphate and oxalate are insoluble in water. The twig tissues contain sharp crystals of calcium oxalate. Triamterene can also cause kidney stones through direct crystallization or by seeding calcium oxalate stones. On heating, sodium formate decomposes to form sodium oxalate and hydrogen. The calcium oxalate crystals produce a peppery flavor. By adding a reagent, here ammonium oxalate, the calcium will precipitate as calcium oxalate. Cerium(IV) oxide is formed by the calcination of cerium oxalate or cerium hydroxide. They form when urine is persistently saturated with calcium and oxalate. Ca forms a white precipitate with ammonium oxalate. The nonsugar content includes many salts, such as calcium, potassium, oxalate, and chloride. Black dyes and gold produced by inorganic means (ferric ammonium oxalate) are more lightfast. "Anthurium" plants are poisonous due to calcium oxalate crystals.