ruthenate

from The Century Dictionary.

• noun A salt which corresponds to the hypothetical ruthenic acid, as potassium ruthenate (K₂Ru-O₄); also formerly used for what is now called a perruthenate, as potassium perruthenate (KRuO₄). Sometimes written rutheniate.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun inorganic chemistry The oxyanion of ruthenium RuO42-; any salt or mineral containing this anion, formally derived from ruthenic acid