They also go by the name "elemental gases." Bromine is always a liquid, while iodine can be a liquid or solid when at room temperature, depending on several factors. All seven are nonmetallic.

Using the industry-leading Elementar vario MICRO cube the Elemental Microanalysis Service is able to accurately determine the percentage composition of carbon, hydrogen and nitrogen and also sulphur ...

A halogen cannot displace itself from a solution of one of its salts, eg potassium bromine would not displace bromine water, so these combinations are not done.