The present invention provides compounds of formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br and I; 10 X is independently selected from the group consisting of H, F, Cl, Br, I, CW.sub.3 and OR on the basis that at least one X is OR; R is independently selected from the group consisting of C(O) (CH.sub.2).sub.m(CF.sub.2).sub.nY and CW.sub.2C(CW.sub.2OC(O)(CH.sub.2)m(CF.sub.2)nY).sub.3; m is an integer from 0 to 2; 15 n is an integer from 2 to 8; Y is C(Z).sub.3; and Z is independently selected from the group consisting of H, F, Cl, Br and I. Such compounds may be utilised as lubricants, for example in heat transfer compositions.

A grease of the invention contains a fluorine synthetic oil as a base oil and an inorganic acid salt that is at least one selected from phosphate, tungstate, sulfate and sulfite. The grease of the invention is suitably usable in a bearing, a gear and the like because of an excellent wear resistance and a low environmental burden.

A highly fluorinated lubricant configured to be adsorbed by an overcoat of a magnetic recording medium. The lubricant may have a structure:

##STR00001## where R.sub.f is CF.sub.2O(CF.sub.2CF.sub.2O).sub.nCF.sub.2 where n is from 1 to about 100, or R.sub.f is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.sCF.sub.2CF.sub.2, CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.sCF.sub.2CF.sub.2, CF.sub.2CF.sub.2O[CF(CF.sub.3)CF.sub.2O].sub.sCF.sub.2CF.sub.2, CF.sub.2O(CF.sub.2CF.sub.2O).sub.r(CF.sub.2O).sub.sCF.sub.2, or CF.sub.2O(CF.sub.2CF.sub.2O)CF.sub.2and r, s are independently from 1 to about 100, and R.sub.1 is a fluorinated hydrocarbon having a functional group terminating in OH.

The present invention provides compounds of formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br and I; 10 X is independently selected from the group consisting of H, F, Cl, Br, I, CW.sub.3 and OR on the basis that at least one X is OR; R is independently selected from the group consisting of C(O) (CH.sub.2 ).sub.m(CF.sub.2 ).sub.nY and CW.sub.2C(CW.sub.2OC(O)(CH.sub.2 )m(CF.sub.2 )nY).sub.3; m is an integer from 0 to 2; 15 n is an integer from 2 to 8; Y is C(Z).sub.3; and Z is independently selected from the group consisting of H, F, Cl, Br and I. Such compounds may be utilised as lubricants, for example in heat transfer compositions.

What is provided is a fluorine-containing ether compound represented by the following formula.
R.sup.1CH.sub.2R.sup.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OCH.sub.2R.sup.3CH.sub.2R.sup.4
(In the formula, R.sup.2 and R.sup.3 are perfluoropolyether chains, and R.sup.1 and R.sup.4 are terminal groups having two or three polar groups, in which individual polar groups are bound to different carbon atoms and the carbon atoms to which the polar groups are bound are bound to each other via a linking group having a carbon atom to which the polar groups are not bound).

The present invention provides a contact member that strikes a balance between low electrical resistance and sliding durability under the condition of load as low as about 0.1 N. A contact member of the invention has a metal base and a coating disposed on at least part of the metal base. The coating contains fluorinated oil having a polar group, and metal particles surface-treated with a fluorine-based compound having a polar group.

The present invention provides a contact member that strikes a balance between low electrical resistance and sliding durability. A contact member of the invention has a metal base and a coating disposed on at least part of the metal base. The coating contains fluorinated oil having a polar group, and metal particles surface-treated with a fluorine-based compound having a polar group.