''Ex nihilo'' creation

The Latin phrase ex nihilo means "from nothing".
The Wikipedia page Creatio ex nihilo gives a good overview of beliefs about creation, whether ex nihilo or from material that was already existing — frequently believed to be water.

C. C. Walker gives the traditional Christadelphian view:

No such idea as “creation out of nothing” is to be found in the Holy Scriptures. The idea is as unscriptural as it is unscientific. The doctrine of the Bible is that there is only One Uncreate, that is God, and that “out of him are all things” (1 Cor. 8:6). God is spirit (Jno. 4:24), and out of spirit radiating from His person all things have been created. The meaning of the verb bara is in harmony with this. If Moses had said God created all things out of nothing, the objections of science would have been of some weight, since all observation and experiment sustain the maxim ex nihilo nihil fit, out of nothing nothing comes. But he did not say so, but used this verb, the primary notion of which, says Gesenius, is “to cut, to cut out, to carve.” The notion of breaking, cutting, separating, he says, is inherent in the radical syllable bar, as is evident in other similar forms. This is at once scriptural and scientific. The universe is but the separated differentiated substance of God. This is not pantheism, for it recognises the distinction between the personal “Father in Heaven,” and His works, with which, to their remotest bounds, He is in touch by His Spirit.

— Walker, C C, Genesis, The Christadelphian Magazine: Vol 47 (1910), p 223

Bro Roger Evans suggests in passing that the primeval chaos was created ex nihilo prior to the work of the six days of Genesis.