def new_site(name, rgba=RED, pos=(0, 0, 0), size=(0.005,), **kwargs):
    """
    Creates a site element with attributes specified by @**kwargs.

    Args:
        name (str): site name.
        rgba: color and transparency. Defaults to solid red.
        pos: 3d position of the site.
        size ([float]): site size (sites are spherical by default).
    """
    kwargs["rgba"] = array_to_string(rgba)
    kwargs["pos"] = array_to_string(pos)
    kwargs["size"] = array_to_string(size)
    kwargs["name"] = name
    element = ET.Element("site", attrib=kwargs)
    return element