PHILADELPHIA — Island View Crossing, a 179,673-square-foot office building at 1414 Radcliffe St. in Bristol sold for $12.5 million, or $70 a square foot.

A partnership involving Red River Asset Management of New York and Arlington Group Real Estate of Conshohocken bought the building. Lenox, its anchor tenant, signed an 11-year extension on 100,000 square feet at the property, which will be renamed the “Lenox Building.” Other tenants include Staples and Strategic Distribution Inc., both of which use the building as headquarters. Michael Margolis,David Dolan, Brett Segal and Jim Dugan of Newmark Grubb Knight Frank arranged the transaction.