"vacant expanse" is correct and usable in written English.
You can use it to describe an open area that has no buildings or other features. For example: "The car drove past the vacant expanse of desert, stretching as far as the eye could see."
A vacant expanse of skate-scarred ice sprawled before me like a wrinkled cotton sheet awaiting an ironing.
Fortune and I changed elevators and went to one of the top floors, a vacant expanse with views in every direction: a forest of elevator shafts.
But the parcel known as Block 37 is 2.8 acres of raw concrete, empty but for a dilapidated power-company substation, a vacant expanse that a succession of mayors and developers have named but never tamed.
But Weir had his own peculiar and very hilly terrain in front of him in Connecticut, and this geological fact made him into something like a proto-Abstractionist. Two-thirds of a painting, starting at the bottom, might be an vacant expanse.
On a vast, mostly vacant and formerly rubble-strewn expanse of the South Bronx, 35 three-family town houses, their two-tone facades set back behind modest gates and greenery, have been snatched up by eager buyers.
Across the street was a vacant two-hundred-and-twenty-acre expanse of land, the site of a former city garbage dump, which reached to the East River.
DWARFED by the soaring expanse of the long-vacant Kingsbridge Armory, a small group of bike advocates and Bronx residents strolled through the main hall recently and imagined a mecca of bicycling.
When he went to see the 1899 building, he was equally undaunted by what surrounded it: the vacant lots on either side, the large expanse of overgrown land behind and the neighboring house that appeared to be collapsing.
A dozen blocks away, not far from a vast expanse of metal scrap yards and vacant warehouses, the sleek black-and-white cars glide past wooden skeletons for dozens of luxury town houses.
It was a huge expanse of rubble and dirt left vacant when the credit crunch and subsequent crash meant that the shopping-centre giant Westfield decided to halt its plans for a huge new development.
The proposed project in Lake View Terrace worried neighbors, who thought that the expanse of solar cells slated for a vacant lot off Foothill Boulevard would clash with a tranquil, rural area speckled with horse stables and homes.
