A lubricant composition, including 20 to 99.5 wt. %, based on a total weight of the lubricant composition, of a base oil, the base oil having a solubility for ionic liquid methyltrioctylammonium-bis(fluorosulfonyl)imide of at least 3 wt. % at a room temperature of 20 C. The base oil contains a base stock A in a proportion of at least 50 wt. %, based on a total weight of the base oil, the base stock A having a solubility for the ionic liquid methyltrioctylammonium-bis(fluorosulfonyl)imide of at least 3 wt. % at a room temperature of 20 C. The lubricant composition further includes 0.5 to 80% wt. %, based on the total weight of the lubricant composition, of an ionic liquid whose anion is bis(fluorosulfonyl)imide.

A lubricating grease composition, including 20 to 96.5 wt %, relative to a total weight of the lubricating grease composition, of a base oil, the base oil containing a basic oil A in a proportion of at least 50 wt %, relative to a total weight of the base oil, wherein the basic oil A is an ester and/or a polyglycol containing unsubstituted ethylene units as a carbon group in a repeating unit. The lubricating grease composition further includes 0.5 to 80 wt %, relative to the total weight of the lubricating grease composition, of an ionic liquid, the anion of the ionic liquid being bis(fluorosulfonyl)imide and 3 to 35 wt %, relative to the total weight of the lubricating grease composition, of a thickener selected from urea, lithium simple soaps, metal complex soaps of elements of the first and second main group of the periodic table, lithium complex soaps, and mixtures thereof.

An organophosphorus compound has a structure represented by the general formula (I): ##STR00001##
The functional groups are defined in the description. The organophosphorus compound has prominent bearing capacity and excellent antiwear and antifriction performances, and can be used as an extreme pressure antiwear additive and used in lubricating oil and lubricating grease.

A lubricating grease composition, including 20 to 96.5 wt %, relative to a total weight of the lubricating grease composition, of a base oil, the base oil containing a basic oil A in a proportion of at least 50 wt %, relative to a total weight of the base oil, wherein the basic oil A is an ester and/or a polyglycol containing unsubstituted ethylene units as a carbon group in a repeating unit. The lubricating grease composition further includes 0.5 to 80 wt %, relative to the total weight of the lubricating grease composition, of an ionic liquid, the anion of the ionic liquid being bis(fluorosulfonyl)imide and 3 to 35 wt %, relative to the total weight of the lubricating grease composition, of a thickener selected from urea, lithium simple soaps, metal complex soaps of elements of the first and second main group of the periodic table, lithium complex soaps, and mixtures thereof.